PosVim Quick Start Manual

My first reliability analysis project

Guangzhou Baoshun Information Technology Co., Ltd.

2018.07.06

I

Catalog

1 Create project ............................................................................................................................................1

2 Input Product Structure Information ....................................................................................................2

2.1 Manual addition of product structure information ...............................................................3

2.2 Import product structure information through EXCEL file ...............................................6

2.3 Other operations and instructions ............................................................................................9

3 reliability prediction .............................................................................................................................. 11

3.1 Reliability prediction of manual mode ................................................................................ 11

3.2 Intelligent Reliability Prediction ........................................................................................... 13

3.3 Reliability Prediction of Mechanical Parts ......................................................................... 15

3.3 T-S simulation ........................................................................................................................... 16

3.4 failure statistics .......................................................................................................................... 17

3.5 report export ............................................................................................................................... 18

3.6 Other operations and instructions ......................................................................................... 18

4 Reliability Modeling (RBD) ............................................................................................................... 19

4.1 Creating Project and Product Structure Tree ...................................................................... 19

4.2 Creating mission Profiles(optional) ...................................................................................... 19

4.3 Create RBD ................................................................................................................................ 21

4.4 Drawing RBD ............................................................................................................................ 25

4.5 Setting RBD Node Parameters .............................................................................................. 26

4.6 RBD calculation ........................................................................................................................ 28

4.7 RBD Failure Rate Parameter Settings .................................................................................. 29

4.8 Creating Complex RBD .......................................................................................................... 30

4.9 sub graph management ............................................................................................................ 36

4.10 Add Node Pictures ................................................................................................................. 39

4.11 Result Viewing and Output .................................................................................................. 39

4.12 Other operations and instructions ....................................................................................... 40

5 Reliability allocation ............................................................................................................................. 41

5.1 reliability allocation.................................................................................................................. 41

5.2 Adjustment of Allocation results .......................................................................................... 43

5.3 Allocation of Fixed Element Reliability .............................................................................. 44

5.4 Settings do not participate in allocation .............................................................................. 44

5.5 Other operations and instructions ......................................................................................... 45

6 FMEA analysis ....................................................................................................................................... 46

6.1 Analytical method and standard predefinition ................................................................... 46

6.2 FMEA analysis .......................................................................................................................... 46

6.3 control plan &DVP ................................................................................................................... 51

6.4 Convert to Fault Relation Diagram....................................................................................... 53

6.5 Convert to Fault Tree ............................................................................................................... 53

6.5 Fault Mode Library Management ......................................................................................... 54

6.6 Computing configuration ........................................................................................................ 56

6.7 Detection Method Library Management ............................................................................. 58

6.8 Management of Fault Correction Action Lib ..................................................................... 58

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7 Fault tree analysis .................................................................................................................................. 59

7.1 create fault tree .......................................................................................................................... 59

7.2 Fault Tree Computation and Analysis ................................................................................. 63

7.3 Multifunctional/Common Cause Analysis .......................................................................... 64

7.4 Other operations and instructions ......................................................................................... 66

8 Derating Analysis .................................................................................................................................. 67

8.1 Derating Standard Selection ................................................................................................... 67

8.2 Setting of Derating Parameters .............................................................................................. 67

8.3 Conformity Check of Derating .............................................................................................. 68

8.4 report output ............................................................................................................................... 68

8.5 Custom derating Criteria ......................................................................................................... 68

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Description: This quick-use manual describes in detail how to operate from project creation,

product structure tree establishment, reliability prediction, reliability modeling, reliability allocation,

FMEA, FTA to derating analysis through a demo project "My first project". Its purpose is to have

an overall understanding of all functional modules of PosVim.

PosVim is an integrated platform for reliability, maintainability, safety, testability,

supportability analysis. It contains forty modules including Reliability Prediction, Reliability Model,

FMECA, FTA, RCMA, OMTA, LORA, LCC, ALT, Weibull analysis, POF, etc. The trial version

of PosVim just provide six modules (Reliability Prediction, Reliability Model, Reliability

Allocation, FMECA, FTA, Derating analysis). If you are interested in the other modules, you can

contact with us.

Phone:+86 20-89855283

Email: hjy@baoshunkj.com

http://www.baoshunkj.com

1 Create project

After login to PosVim software, click on "Create a new project" and open the

editing window for creating a new project, as shown in Figure 1-1.

Enter the project name "My first project" (name can be taken by yourself), and

select the project manager, responsible department. The project name must be entered,

other information can be empty. As shown in Figure 1-2.

Click the Save button to create a project. After successful creation, the system

automatically opens the current project.

Note: If you have created a project, you don’t need to create it, just open it.

Figure 1-1 Enters the Welcome Window

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Figure 1-2 project creation

2 Input Product Structure Information

After opening the newly created project "My First Project", the following Window

is displayed. As shown in Figure 2-1.

PosVim subsequent reliability prediction, FMEA, reliability modeling, reduction

design, maintainability prediction, maintainability allocation and other modules need

to use product structure tree information. So, after creating a project called "My First

Project", the first thing I recommend is to input information about the composition and

structure of the product. PosVim provides two ways to input product composition

structure information. One is to add them manually one by one; the other is to import

them through excel template files.

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Figure 2-1 open the project

2.1 Manual addition of product structure information

2.1.1Create root node

After opening the project, right-click in the blank of the "Product Structure Tree"

window on the left side of the main Window and select the "Add sub-nodes" option of

the pop-up menu, or click directly on the icon above the Window to add sub-nodes, as

shown in Figure 2-2.

In the pop-up "Edit Node" information window, enter basic information such as

node name. For example, enter "XXX System" in the node name inputbox, and select

"System" in the drop-down list for the node type. At this point, the root node was

created successfully. As shown in Figure 2-3.

Note: It is important to note that when creating a node, remember to select the

type of node (PosVim product type is divided into system, subsystem, equipment,

module, board, components, mechanical components, computer software, etc.).

Otherwise, the system defaults that the node is a component/module, and later when

carrying out reliability prediction, it is impossible to use GJB/Z 299C, SR332 and

other standards for reliability prediction.

Product Structure Tree

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Fig. 2-2 add node

Figure 2-3 Creates the root node

2.1.2 Enter child node information

Assuming that the object of our analysis is "XXX system", there are two modules

under the root node "XXX system", namely module A and module B. There are several

components under Module A and Module B. The operation steps of inputting the sub-

node information of the root node "XXX system" are as follows:

Step 1: First, add the sub-node of module A under the root node "XXX system":

click on the root node "XXX system", and then click on the right-click menu to select

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"Add sub-node" or click directly on the icon above the Window to add sub-nodes. Enter

node information "Module A" and select "Module" for node type. As shown in Figure

2-4.

Step 2: Under the created "Module A" node, add components belonging to Module

A. The way to create is:

Select the "Module A" node, right-click on the pop-up menu, select "Add sub-

nodes" or click the icon above the Window directly to add sub-nodes. Input sub-node

information "2CW52", type selection "diode". As shown in Figure 2-5.

Using the same method, select "Module A" node, add sub-nodes "EPM703" and

"RJ45-01" respectively, and select "microcircuit" and "fixed resistor" respectively. If

necessary, you can continue to add components that need to be predicted. The operation

method is the same.

Step 3: In the same way, module B nodes parallel to module A are created. Under

module B, there are component resistors "RJ4501", "RJ4502" and mechanical parts

"M01". Refer to step 2 for the addition node of component resistors "RJ4501" and

"RJ4502". When adding mechanical parts "M01", the node type can be selected as

"mechanical parts". As shown in Figure 2-6.

Figure 2-4 Adding "Module A" Node

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Figure 2-5 Component Nodes for Adding Module A

Figure 2-6 Mechanical component M01 with module B added

2.2 Import product structure information through EXCEL

file

In addition to the above component node information added manually one by one,

PosVim provides product information imported through Excel files. When importing

excel format files, the Excel file format should meet the template requirements provided

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by PosVim. Template “SysTree. XLS” can be found in the PosVim installation

directory.

Operation procedure:

Step 1: Create Excel files in the template format provided by PosVim (see

\Template\SysTree.xls'in the PosVim installation directory).Keep in mind to

check whether the format conforms!!!

Step 2: Assuming that the components of Excel file are imported under module A

of XXX system, the operation method is as follows:

2A: Select Module A, then right-click and select the right-click menu "Excel

Import" to open the import editing Window.

2B: Import the editing Window in excel, select the browse button, and select the

excel file you need to import. Here we assume that the components in the template file

“SysTree. XLS” imported into PosVim are under Module A. Find "\ Template\ SysTree.

xls" in the PosVim installation directory and select it.

2c: Click the import button to import the components in the excel file under module

A. As shown in Figure 2-8a.

After import, a module name ‘Module’ has been imported to the Module A as

SubNode, as shown in Figure 2-8b.

Figure 2-7 import Excel

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Figure 2-8a Imports Components to Module A

Figure 2-8b Module information has been Imported to Module A

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2.3 Other operations and instructions

2.3.1 Product type specification

When creating a product structure tree, remember to select the product category of

the node, otherwise the reliability prediction process may not be able to predict because

the node type cannot be identified. PosVim’s product categories are shown in the

following figure.

Fig. 2-9 product category

2.3.2 Copying and pasting of product structure information

When creating a product structure tree, PosVim supports to copy any node of the

product structure tree, and any level of subtree, and pasting it under the new product

structure tree node. The operation is:

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Copy:Select the node or subtree you want to copy, click on the icon of the toolbar

above the product structure tree form or right-click on "copy" or use the shortcut "CTRL

+ C" to copy.

Paste:Select the node you want to paste node information, click on the icon in the

toolbar, or right-click on "paste" or use the shortcut key "CTRL + V" to complete the

paste.

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3 reliability prediction

PosVim provides manual reliability prediction and intelligent reliability prediction

method, which can be selected according to your demand.

It should be noted that the reliability index obtained by the reliability prediction

module is the basic reliability (usually can be the failure rate λ and MTBF)!!If you need

to get mission reliability index (such as mission reliability), you need to use PosVim’s

RBD module to get them.

Because the prediction mode of PosVim’s reliability prediction module is bottom-

up, that is, starting from the lowest component and component reliability prediction,

the reliability prediction of components is carried out first, then the reliability prediction

is carried out step by step, and then the reliability prediction results of components,

modules, subsystems and systems at all levels are obtained. Therefore, in order to

complete the follow-up reliability prediction work, we first need to establish the product

structure layer by layer according to the product composition structure, until the

component layer. How to construct the product structure tree and input the product

structure information, see Section 2.

3.1 Reliability prediction of manual mode

After creating the information of product composition and structure, click on the

icon of reliability prediction module in "Design Analysis" above the PosVim software

Window, and then the reliability prediction Module will be opened, as shown in Figure

3-1.

PosVim provides commonly used reliability prediction standards, including

GJB299C, SR332, NSWC and other electronic and mechanical components reliability

prediction standards. It is necessary to determine which standards to use for reliability

prediction according to user requirements or reliability prediction requirements.

Reliability prediction usually starts with the lowest components!!It is assumed that

the reliability prediction starts with the component of module A, and then proceeds to

the reliability prediction step by step. Specific operation steps:

Step 1: Confirm that you have opened the reliability prediction module. In the

product structure tree window on the left of the main Window, click on the "Module

A" node. The Window is shown as Figure 3-1 below. On the left side of the Window is

the product structure tree. The middle part shows the list of all the sub-nodes of the

current selected node "Module A", and below is the needed input parameter window of

component reliability prediction.

Step 2: In the list of nodes in the middle part of the software Window, double-click

on the node that needs reliability prediction. For example, double-click on the "2CE52"

node and pop up the reliability prediction parameters that the node needs to input.

Step 3: The choice of reliability prediction method, environment, sub-category

parameters, environment and sub-category options in turn is related to reliability

prediction standard/methods. That is to say, when different reliability prediction

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standard/methods are selected, the choice of environment category and sub-category

parameters is different. The reliability prediction parameters of various components in

GJB299C, SR332, NSWC and other standards can be referred to the corresponding

standards. Assuming that the prediction method chooses "GJB299C stress method", the

environment chooses "GB ground benign ", and the subcategory chooses "General

Silicon diode". As shown in Figure 3-2.

Step 4: After selecting prediction methods/standards, environment categories and

subcategories, the corresponding reliability prediction parameters will pop up

according to the options you choose and need to be input. For example, "2CE52" diode

needs to input quality level, operating temperature and other parameters. As shown in

Figure 3-2.

Step 5: After entering the reliability prediction parameters of components, click on

the calculation above the input window of parameters. Button, the reliability

prediction results of the component can be calculated. As shown in Figure 3-3.

Figure 3-1 Open Reliability Prediction

Product

information

Prediction

parameter input

Prediction result

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Figure 3-2 Reliability Prediction Parameter Input

Figure 3-3 Reliability Prediction Results View

Step 6: According to the same operation method, component reliability prediction

under module A and module B is completed. The reliability prediction results of module

A and module B can be obtained. To view the reliability prediction results of the root

node "XXX system", click "XXX system" on the product structure tree Window on the

left. If you can’t see the result, select XXX System and click on the top of the toolbar

Icon.

3.2 Intelligent Reliability Prediction

In addition to the manual reliability prediction, PosVim also provides an intelligent

reliability prediction method, which can quickly and complete the reliability prediction

Input Parameter here

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work in batch. It can greatly improve the efficiency of reliability prediction work.

Especially when the product naming is more standardized, the one-button batch

predictable 70-80% of the components, greatly improving the efficiency of work.

Assuming that the reliability prediction of module A is needed now, the following

steps are taken to predict the reliability of module A by using intelligent reliability

prediction method:

Step 1:Confirm that you have selected the "Module A" node in the product

structure tree window on the left of the main Window, then click on the icon above the

reliability prediction to pop up the intelligent reliability prediction setup Window. As

shown in Figure 3-4.

Step 2:In the pop-up reliability intelligent prediction setup Window, select a

template. Suppose you choose the ‘satellite’ template. At this point, the window

displays the default setting information of the Satellite template, which can be changed.

For example, to modify the environment to " SF Space, Flight ", just select " SF Space,

Flight " in the environment bar and tick the box in front of "ReplaceBy" to modify the

configuration information in the template (Ps: Modified template can be saved as a new

template for subsequent use). As shown in Figure 3-4.

Step 3: After configuring, PosVim automatically performs reliability prediction by

clicking the Predict button. Please be patient.

Step 4: When you close the Intelligent Prediction Window, you will see that about

70% of the components automatically complete the reliability prediction.

Step 5: Nodes without predicted reliability results may be missing some

parameters. At this point, you need to double-click the components without reliability

prediction results one by one, and then input the missing reliability prediction

parameters, according to the manual reliability prediction method, the reliability

prediction can be done.

So far, the intelligent reliability prediction can be completed. As shown in Figure

3-5.

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Figure 3-4 Reliability Intelligent Prediction Template Configuration

Figure 3-5 Intelligent Reliability Prediction Results

3.3 Reliability Prediction of Mechanical Parts

The former module A contains mainly electronic components. Module B includes

not only electronic components, but also mechanical components. How to predict the

reliability of mechanical components? The operation steps are as follows:

Step 1: Make sure you have selected Module B.

Step 2: In the list of nodes in the middle part of the reliability prediction main

Window, double-click the mechanical component node "M01" that we have created

before.

Nearly 70% components’ prediction

has completed auto.

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Step 3: In the reliability prediction parameter input window below, the NSWC

standard has been selected by default. If it is not, select it manually.

Step 4: In the subcategory of reliability prediction parameter input window, choose

"static sealing, gasket". Note: The specific subcategory of this part needs to be selected

according to the actual situation of your product. The hypothesis here is "static sealing,

gasket ".

Step 5: After selecting the subcategory, the software will display the reliability

prediction parameters that the mechanical parts of this class need to input, and then

input them separately. For specific input of each parameter, refer to NSWC standard.

After inputting the reliability prediction parameters, click the calculation button to

get the reliability prediction results of the mechanical components.

Figure 3-6 Reliability Prediction of Mechanical Components

3.3 T-S simulation

PosVim’s TS simulation function can predict the reliability of products under

different temperature and electrical stress. For example, product A has already carried

out reliability prediction. If product B improves or replaces the platform and

environment based on product A, then TS simulation can be carried out to understand

the inefficiency of improved product B.

Assuming that TS simulation of module A is needed, the operation steps are as

follows:

Step 1: Confirm that you have currently selected Module A. Then click the T-

S simulation button. In the configuration of the pop-up TS simulation Window, two

modes of simulation are provided for selection. One is to simulate by temperature; the

other is to simulate by stress. Let’s assume that the "by-temperature" simulation is

selected.

Step 2: Input temperature start value, step length, cut-off value. Then click the

button to run the simulation.

Step1: Select

Module B

Step2: Select

‘M01’

Step3: Select

‘NSWC’

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Step 3:View the simulation results. After running the simulation, the simulation

results are obtained, as shown in the following figure.

Figure 3-7 T-S simulation results

3.4 failure statistics

After completing the reliability prediction work of all components, you can click

on the product structure tree on the left side of the main Window to view the predicted

results layer by layer. If the predicted results are not updated, you can click on the icon

of the reliability predicted main Window and recalculate it.

Figure 3-8 Failure Rate Statistics

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3.5 report export

After completing the reliability prediction, click the button above to export the

failure rate prediction results of components under the currently selected node (product

structure tree on the left).

3.6 Other operations and instructions

(1) Direct Input Failure Rate

For some components, there is generally no corresponding reliability prediction

standard for you to predict directly. In this case, direct input can be used. Assuming that

node "M01" cannot be predicted by reliability prediction standard, the specific

operation method of direct input failure rate is adopted at this time:

Step 1: Confirm that you have selected Module B.

Step 2: Double-click "M01". In the pop-up reliability prediction parameter input

Window, the calculation method chooses "direct input". In the input box of lambda p,

input failure rate, and then click Button.

Figure 3-9 Direct Input Failure Rate

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4 Reliability Modeling (RBD)

The reliability index obtained by the reliability prediction module is the basic

reliability (usually the failure rate and MTBF)!!If you need to get task reliability index

(such as mission reliability) and analyze the mission reliability of the product, you need

to use the RBD module of to get them.

When using reliability modeling (RBD) to calculate product’s reliability, we need

to consider the relationships model of series, parallel, redundancy and voting of each

component of the product, as well as the working status and duty cycle of each

component in different stages of use.

4.1 Creating Project and Product Structure Tree

How to create a project, see Section 1 ,If created, skip this.

How to create a product structure tree, see Section 2, If created, skip this.

4.2 Creating mission Profiles(optional)

Because the working state of each component of the product may be different in

different time periods during the use of the product. So, it is generally necessary to

establish mission profiles. Of course, if the mission profile is relatively simple, you

don’t need to create the mission profile.

Suppose that the "XXX system" in the new project "My first project" is divided

into two mission phases in the use process. Among them, the duration of mission phase

1 is 0-24 hours, and that of mission phase 2 is 24-48 hours. Mission phase 1 requires

module A and module B to work together, and mission phase 2 requires module B to

work together. For "XXX system", the steps to create the mission profile of "XXX

system" are as follows:

Step 1: Make sure that you have opened a project called My First Project.

Step 2:Click on the Mission Profile Window (or switch to the Mission Profile

Modeling Window by clicking on the Window in the menu bar).

Step 3:After entering the mission profile Window, drag two stage boxes and two

mission nodes from the model list on the right into the task profile drawing area. Stage

boxes enter the names " Mission Stage 1" and "Mission Stage 2" respectively. As shown

in Figure 4-1 below.

Step 4:Double-click on one of the task nodes and name it mission 1. Enter 0 for

start time and 24 hours for end time. Click on the "Associated Products" option and

switch to the editing Window of the Associated Products. Double-click on Module A

and Module B, then add Module A and Module B to the list of related products of

mission 1 automatically. As shown in Figures 4-2 and 4-3 below.

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Double-click on another mission node, named "mission 2", using similar operations

to complete mission time settings and related product settings, related product selection

module B.

Then click on the model list on the right and select the connection line to connect

Mission 1 and Mission 2. As shown in Figure 4-4.

Figure 4-1 Creating Mission Profile

Figure 4-2 Setting Mission Information

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Figure 4-3 Setting up Mission Associated Products

Figure 4-4 Mission Node Connection

Note: PosVim’s mission profile modeling supports hierarchical mission profile

modeling, that is, missions can contain multi-level sub- missions. Select the mission

node, and then select "Open sub-mission" to enter the sub-mission settings Window.

Specifically, you can learn how to create submissions by yourself.

4.3 Create RBD

PosVim’s reliability model (RBD) can be associated with or not associated with

mission nodes in mission profiles. Creating RBD is divided into two modes of operation.

One mode is to select the corresponding mission node from the mission profile and

create the reliability block diagram of the corresponding mission node; the other mode

is to directly enter the reliability modeling (RBD) module, create RBD, and then select

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whether the RBD is associated with the existing mission node. Here are the operation

methods.

4.3.1 Creating RBD of Associated Mission from Mission Profiles

We have created two Mission phases and two mission nodes (mission 1, mission

2) before. The method of creating mission 1’s Relevant Reliability Model (RBD) is as

follows:

Step 1: Make sure you are in the mission profile editing window. In the mission

profile Window, click the Mission 1 node, right-click and select Create RBD.As shown

in Figure 4-5.

Figure 4-5 create RBD

Step 2:In the RBD Create Edit Window, enter information in the following format.

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Figure 4-6 Editing RBD Basic Information

Step 3:After clicking save, you can enter the RBD modeling Window, which is

as follows.

Fig. 4-7 main window of RBD

Step 4:After completing the creation of RBD, enter the drawing RBD operation,

see section 4.4.

RBD Model Lib RBD Draw RBD Node List

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4.3.2 Create RBD directly

The method of creating RBD directly is as follows:

Step 1:Select the "RBD" icon in the "Design Analysis" section of the menu bar

and click Open. At this point, the RBD management window pops up and the basic

information of the created RBD needs to be input. Like the following diagram.

Figure 4-8 Creating RBD Records

Step 2:click Add an RBD record. Pop up the window shown in Figure 4-6

and enter the information like the following window. The name "RBD of Task 2" and

the mission Name drop-down list select " mission 2".

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Figure 4-9 Setting up RBD Basic Information

Step 3:Click save button. At this point, it will open a window similar to Figure 4-

7.

Step 4:After completing the creation of RBD, enter the drawing RBD operation,

see section 4.4.

4.4 Drawing RBD

After creating the RBD record (assuming the example of "RBD of mission 1"

created in the previous section 4.3.1), the RBD graph can be drawn. Specific

operation:

Step 1:From the list of RBD model libraries on the right side of the RBD

Window, drag two nodes unit (node 1, node 2) to the drawing area, and then connect

the start node, node 1, node 2, and end node respectively. As shown in the following

figure.

Note: The above drag and drop is a simple single node model. You can drag

and drop other complex nodes to create RBD. For example, drag and drop from the

list of RBD models includes parallel, redundant, voting (k out of n) and other

nodes.

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Figure 4-10 Creates two cell nodes

4.5 Setting RBD Node Parameters

Configuring RBD node parameters is the key work of RBD modeling and

calculation. The specific operation is as follows:

Step 1: Edit unit node information. Double-click on node 1 and pop up the node

information editing window like following diagram. Associate product selection

"Module A". The default node type is "unit". You can also change it to series group,

parallel group, etc. If you change it to series group or parallel group, you need to input

the number of combined units and other information.

Figure 4-11 Associate Product Settings

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Step 2: Select reliability prediction for failure rate data source. PosVim provides

direct input, distribution calculation, reliability prediction, reliability evaluation and

other ways to input failure rate data. Here we choose [Reliability Prediction] to obtain

the reliability prediction data of module A that we have already done. As shown in the

following figure.

Figure 4-12 Failure Data Source Settings

Step 3:Click the Compute button. The reliability calculation results of the joint can

be obtained. As shown in Figure 4-13.

Step 4:Click on the Mission/system Reliability Display Box , Mission/system

reliability curves at different times can be viewed. As shown in Figure 4-13 below.

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Figure 4-13 Reliability versus time curve

Step 5:After double-clicking on node 2, the same method is used to set the

parameters of cell node 2.The product associated with Unit 2 is Module B.

4.6 RBD calculation

After completing the configuration of node parameters, the whole RBD diagram

can be calculated (Note: If there are nodes without configuration parameters, the

software PosVim will prompt the lack of data, and marked with red).

The RBD calculation operation is as follows:

Step 1After setting the parameters of Unit Node 1 and Unit Node 2, click on the

toolbar Calculate reliability. At this point, the corresponding list of reliability

calculation results is displayed below. As shown in the following figure.

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Figure 4-12 Reliability Calculations

4.7 RBD Failure Rate Parameter Settings

As mentioned above, when setting the failure rate parameters of nodes, we can

choose the way of directly inputting reliability, calculating according to distribution,

obtaining reliability prediction results, and obtaining reliability distribution results.

Direct Input Reliability: In the pop-up node parameter editing window, the data

source is selected as "reliability" and then input directly.

Figure 4-13 Direct Input Reliability

According to the distribution calculation: In the pop-up editing window of node

parameters, the data source chooses "Distribution Computation", then chooses the

distribution type, and inputs the distribution parameters. For example, select

exponential distribution and input failure rate. When choosing different distribution

types, the input parameters are different.

Figure 4-14 is calculated by distribution

Obtain reliability prediction data: The data of each module of PosVim is highly

integrated to ensure data consistency of each module and improve work efficiency.

RBD module can obtain reliability prediction and reliability allocation data. The

methods of obtaining reliability prediction data are as follows:

Reliability Result

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(1) In the associated product input box, the corresponding nodes in the product

structure tree must be selected. Otherwise, reliability prediction data cannot be obtained.

For example, if you want to obtain the reliability prediction data of Module A as the

failure rate data of Unit Node 1, select Module A in the drop-down list of related

products.

(2) Select the "Reliability Prediction" option at the data source.

Figure 4-15 Obtaining Reliability Prediction Data

Obtain reliability allocation data: The method of obtaining reliability

distribution data is the same as that of obtaining reliability prediction data.

4.8 Creating Complex RBD

The previous RBD model is relatively simple, with only two nodes in series. This

part describes in detail how to create a complex RBD model. The RBD model includes

series group, parallel group, K-out-of-N, subgraph and so on.

Step 1: Select

associated Node

Step 2: Select

‘Reliability Prediction’

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Step 1:click Icon, create a record named "Complex RBD" directly like section

4.3.2.The name of RBD is entered into "Complex RBD". The system belongs to "XXX

System". The name of mission is left blank (or mission 1 and mission 2 established

earlier) and the time of mission is input for 24 hours. Click save.

Figure 4-16 Creating RBD Records

Step 2: Add a series group (the same unit).This method can be applied to the

case of multiple units connected in series. From the list of RBD models on the right,

click on the model icon and drag it to the drawing area to create a series group. Double-

click on the serial group node, in the pop-up node attribute form, the associated product

selection module A, the node category selection "serial group", the total number of

devices input 2 (can input any natural number), and the reliability prediction of data

source selection. Click on the calculation to get the reliability results of this series group.

32

Figure 4-17 Setting Series Group Parameters

Step 3: Add a series group (different units).The previous addition is a series

group made up of the same units. Here we create a series group made up of different

units. Operation procedure are:

3A:From the RBD model library on the right of the RBD main Window, Click

Icons (note that the two colors are different) and drag them to the drawing

area. At this point, the number of windows in series will pop up the input prompt box,

input number 2.After clicking on the confirmation, the Window shown in Figure 4-19

is displayed, and two series nodes of Unit 3 and Unit 4 are added.

3b:Double-click on node 3 and node 4 respectively to configure node parameters.

The specific configuration method refers to Section 4.5.

Input Series Node Num

Default mission time

33

Figure 4-18 Setting the Number of Series

Figure 4-19 Drawing Window for Series Groups

Step 4: Create the K out of N (the same unit). K out of N is a commonly used

model in reliability modeling, such as radar equipment. Specific operation methods:

4A:From the RBD model library on the right of the RBD main Window, Click

Drag and drag the icon to the drawing area.

4b:Double-click K out of N, in the pop-up editing window of node attributes, select

"Module B" for the associated product, select "Redundant Group" for the node type,

and input 2 for the total number of devices required (2 out of 3 devices are required,

and the system works normally).Failure rate data source selection reliability prediction,

click calculation and save. As shown in the following figure.

Figure 4-20 Add N out of K nodes

34

Figure 4-21 Setting N for K-node parameters

Step 5: Create a subgraph. For complex RBD, in order to display RBD structure

better and understand RBD structure relationship better, sometimes we need to use

subgraph to display part of RBD model in subgraph. Or when RBD diagrams are

created by different people and departments, you can use the RBD diagrams created by

others as sub-diagrams and aggregate and embed them into the RBD diagrams you draw.

Specific operation methods:

5A:From the list of RBD models on the right side of the main RBD Window, drag

a unit node to the drawing area. Of course, in the actual use process, you can also change

a node in the drawing area to a subgraph. The way to change the subgraph is to double-

click the node, and then change the node into a subgraph in the pop-up form of node

attributes. See Section 4.9 for details.

5B:In the pop-up edit window for node attributes, the subgraph category selects

"direct subgraph". Then click Save. At this point, the node icon of the main Window

becomes an icon with a "+" number.

35

5C:Double-click the "+" number of the node icon, or select the node, right-click

the menu "Open Subgraph" and enter the modeling Window of the subgraph. Subgraph

modeling is the same as normal RBD modeling. Here, we create a series group in the

subgraph, connect the start node, the series group and the end point, and configure the

node parameters of the series group (see step 2).As shown in Figure 4-23.

5D:After creating the subgraph, Click Icon, go back to the top layer.

Figure 4-22 create subgraph

Fig. 4-23 subgraph rendering

Step 6:In the order shown in Figure 4-24 below, connect the previously created

series group, K out of N, and sub-graph nodes. Then click on the calculation to get the

calculation result of the complex RBD.

Select ‘create Subdiagram

directly’

36

Figure 4-24 RBD calculation

4.9 sub graph management

For complex systems, subgraphs are sometimes needed to better represent the

relationships among RBD modules. In addition, the RBD model of complex systems is

relatively large and complex, at this time, different people may be responsible for

different RBD model construction, and need to use subgraphs to aggregate different

people’s RBD diagrams.

Based on the above considerations, PosVim provides subgraph management

functions.

4.9.1 Direct subgraph

Direct subgraph is to add a subgraph directly in the current RBD model. By using

the function settings of subgraphs, the hierarchical construction of RBD diagrams can

be achieved.

Methods of operation:

Step 1: Verify that you have entered the reliability block diagram RBD

module.

Step 2:Create RBD record. See Section 4.3 for details. Suppose you create an RBD

record called Subgraph Test RBD.

Step 3:From the list of RBD models on the right side of the main RBD Window,

drag a unit node into the drawing area.

Step 4:Double-click the node. In the node property editing window, the node name

is changed to "Subgraph 01" and the subgraph category is changed to "Direct Subgraph".

At this point, the node icon of the main Window becomes an icon with a "+" number.

37

Figure 4-25 set the subgraph

Step 5:Double-click the "+" number of the node icon, or select the node, right-

click the menu "Open Subgraph" and enter the modeling Window of the subgraph.

Subgraph modeling is the same as normal RBD modeling. After building the subgraph,

Click Icon, go back to the top layer. At this point, the sub-graph settings are

completed.

4.9.2 Reference subgraph

Reference subgraphs are a very useful function. For example, when different

people are in charge of different subsystems and establish RBD diagrams of subsystems

respectively, the RBD diagrams of the whole product or system can be directly

referenced when the RBD diagrams of the whole product or system are established. Or

references to RBD diagrams between different projects. Specific operation mode:

38

Step 1:Assuming that through Section 4.3, two RBD subgraphs "RBD for Task 1"

and "RBD for Task 2" have been created. If not, you can refer to Section 4.3 steps for

creation.

Step 2: Make sure that the project name you open is "My first project" and

has entered the RBD modeling module.Create RBD record.See Section 4.3 for details.

Suppose that you create an RBD record called Reference Subgraph Test RBD.

Step 3:From the list of RBD models on the right side of the main RBD Window,

drag two nodes (node 1, node 2) into the drawing area.

Step 4:Double-click on cell node 1. In the pop-up node attribute form, the sub-

graph type chooses "Reference Subgraph" and the association subgraph chooses "RBD

of Task 1". Similarly, double-click on cell node 2 and select "RBD of Task 2" from the

association subgraph.

Step 5:When the configuration is completed and the above nodes are connected,

the calculation results can be obtained by clicking the calculation button.

Fig. 4-26 subgraph

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4.10 Add Node Pictures

In order to display RBD graphical structure more vividly, PosVim supports setting

background pictures of each node when drawing RBD model. Operating mode is:

double-click the node that needs to configure the picture, in the pop-up editing Window

of node attributes, in the blank input box on the right side of the [node picture], right-

click, and then select "Call" to browse the picture you need to import.

Figure 4-27 Sets the Node Background Picture

4.11 Result Viewing and Output

After the RBD modeling and calculation are completed, the RBD calculation

results can be viewed.

Select any node in the RBD model and click on the one above the toolbar The

reliability parameters of the current node can be calculated.

Without selecting any nodes, in the case of the currently open RDB model, click

on the top of the toolbar In this way, the reliability parameters of the whole RBD

diagram can be calculated.

click The overall reliability calculation results of the currently open RBD model

can be viewed.

click RBD diagrams can be exported.

click The results of RBD calculation in EXCEL file format can be exported.

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4.12 Other operations and instructions

RBD results show that:

Basic reliability:Basic Reliability means the probability that the product will

complete the specified function within the specified time and under the specified

conditions. It is recorded as R (t), also known as the reliability function. The basic

reliability is to treat the composition and structure of the product as a series connection,

and then calculate according to the above calculation formula.

Mission reliability: Different from the basic reliability, mission reliability is

calculated according to the logical relationship model of series-parallel fault of the

product and the formula.

MTBF:MTBF is the average value of product failure interval time. For example,

in the use of a product, N failures occur, and each failure is repaired and then continue

to work.MTBF is the average time between failures.

MTBCF:Average critical or fatal fault intervals.Unlike MTBF, the failures

considered here are only fatal or critical failures.MTBF is a failure whether it is fatal or

critical.Therefore, the calculated MTBCF value is larger than that of MTBF.

PDF:probability density function

Harzard graph:It is the ratio of failure rate to reliability. That is the value of

f(t)/R(t).

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5 Reliability allocation

Reliability allocation is top-down method, and the top-level reliability index are

allocated to each subsystem and module layer by layer.

5.1 reliability allocation

Reliability allocation is easier to operate than reliability prediction and reliability

modeling RBD. Assuming that a project named "My First Project" has been created and

a product structure tree with the root node of "XXX System" has been established, the

reliability index of "XXX System" will now be assigned to module A and module B.

Operation procedure:

Step 1:To create a project, see Section 1.If created, skip and open the project

directly. Let’s assume that we have created the project "My First Project" according to

Section 1.Open the project directly.

Step 2:To create a product structure tree, see Section 2.If created, skip. Let’s

assume that we have created the product structure tree in accordance with Section 2,

and we don’t need to create any more.

Step 3:Confirm that you have opened "My First Project" and opened the reliability

allocation module. Select "XXX System" in the product structure tree on the left. As

shown in the following figure.

Figure 5-1 enters the reliability allocation Window

Step 4: Select the allocation method. According to the user’s requirements or the

requirements of the project itself, the specific reliability allocation method is

determined. For the detail information of various allocation methods, reference to the

corresponding books or standard materials. Here, suppose we choose the "AGREE

allocation method". At this point, the system reliability and reliability redundancy input

box on the right becomes editable.

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Fig. 5-2 Allocation Method Selection

Step 5: Input allocation index. Because the selected allocation method is AGREE

allocation method, the reliability index that can be allocated is considered. Input

allocation of system reliability index (that is, input the index you need to allocate

downwards) 0.96, reliability redundancy input 0.1 (generally retain a certain reliability

allocation redundancy in engineering), or left blank. For the meaning of reliability

allocation redundancy, see section 5.5.

Figure 5-3 Setting of Allocation Index

Step 6: Input allocation parameters. Choosing different allocation methods

requires different allocation parameters to enter. The AGREE method is chosen here,

which requires input including mission time, number of components, and importance

factors. Enter the corresponding parameters as shown in the figure below.

Step 7: Allocation calculation. Click to complete the allocation calculation. The

results are shown in the following figure.

Figure 5-4 Allocation results

Step 8: Allocation adjustment. The allocation results need to consider

comprehensively the realizability. Therefore, the allocated results may need to be

adjusted. See Section 5.2 for the method of operation. It is assumed that the allocation

result of module B is adjusted to 0.98.

Figure 5-5 Allocation results adjustment

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Step 9: The next level of allocation. Through steps 1-8, the allocation results of

module A and module B have been obtained. Suppose we need to continue allocating

now. Taking module B as an example, the allocation results of module B are further

allocated to the next layer. Specific operation steps:

9A:In the product structure tree on the left side of the main Window of reliability

allocation, select "Module B". At this time, the reliability allocation index of Module B

needs to show 0.98, indicating that the allocation results of the previous level have been

automatically obtained (of course, the data can be modified).

9b:According to steps 4-6, the allocation method selection, allocation index setting

(the result of the previous layer has been obtained by default) and allocation parameter

input are completed respectively.

9C:Click on the allocation calculation to get the result of the downward allocation

of module B index. As shown in the following figure.

Figure 5-6 Next Level (Module B) Allocation results

5.2 Adjustment of Allocation results

According to the previous selection of the appropriate allocation method to obtain

the reliability allocation indicators at all levels of the product, sometimes it is necessary

to adjust the allocation results of individual subsystems and modules, such as the

allocation of indicators to rectify processing, or research and development of high-risk

equipment needs to reduce the reliability index requirements. At this point, you need to

use the allocation result adjustment function.

Assume that the reliability index assignment of XXX system has been completed

according to Section 5.1. Now the allocation results need to be adjusted.

Step 1:In the column of "Adjusted Reliability", the results of reliability allocation

can be adjusted separately. For example, the reliability allocation result of module A is

adjusted from 0.966554 to 0.97, and that of module B from 0.980749 to 0.98.

Fig. 5-7 Reliability Allocation Result Adjustment

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5.3 Allocation of Fixed Element Reliability

In reliability allocation, we often encounter the situation that the reliability index

of some components is known. At this time, when reliability allocation is carried out,

the reliability index of these components can be set to be fixed. Then the reliability

allocation is carried out.

Assuming that Module B contains three components, the reliability requirement of

Module B is 0.98 (the result of upper level assignment), and the reliability index of M01

mechanical component is known to be 0.99. Then the operation steps of reliability

allocation of module B are as follows:

Step 1:Assuming that the reliability allocation is made according to step 1-8 of

Section 5.1, the reliability allocation result of Module B is obtained.

Step 2:In the product structure tree, module B is selected, and then the allocation

method is "AGREE allocation method", and the reliability allocation index is 0.98 (the

result from the allocation from the upper level).

Step 3:When input reliability allocation parameters, in the fixed reliability column

of M01 node, input 0.99.Then input the task time, number of components, importance

factor and other parameters of each component according to the figure below.

Step 4:Click on the button to get the reliability allocation results, as shown in the

following figure.

Fig. 5-7 Fixed Reliability Allocation

5.4 Settings do not participate in allocation

In the process of product development, some components and components are

mature products and generally do not participate in reliability allocation. At this time,

in the development of reliability allocation, only the corresponding components

involved in the allocation can be checked out.

Figure 5-8 Settings Do not Participate in Allocation

45

5.5 Other operations and instructions

Allocation method: Choosing different allocation methods, the reliability index

that can be allocated are different. When selecting the allocation method, system

reliability, MTBF and failure rate can be allocated; when AGREE method is selected,

system reliability can only be allocated. When selecting the allocation method and

grading allocation method, the system reliability, MTBF, failure rate and other

indicators can be allocated. You can input one of the index. Of course, you can also

enter multiple indicators.

System reliability:This column asks you to enter the reliability index you want to

allocate down. For example, the reliability requirement of the system is 0.9, which

requires that the index of 0.9 be allocated downwards. Then, enter 0.9 in the column of

system reliability.

Reliability redundancy: When carrying out reliability allocation in general

engineering, it is necessary to consider whether the target can be achieved in the later

development process, and some uncertain factors in the later development process may

affect the realization of the target. In order to ensure the success of product development,

there is a certain margin in general distribution. Therefore, when using PosVim to carry

out reliability allocation, if you don’t want to retain the margin, enter 0 in the column

of reliability margin (software default); if you want to retain the margin, enter 5%~15%.

The software will be allocated according to the system reliability input and the

corresponding reliability margin.

MTBF redundancy: It is similar to reliability redundancy.

Failure rate redundancy: It is similar to reliability redundancy.

Fixed reliability: When the reliability of the node is known or it is considered that

the node does not use the value assigned by the reliability allocation result, the

reliability value of the node is input directly.

Adjusted reliability: After selecting the reliability allocation method for

allocation, the distribution results of each node are obtained. When the general

distribution results are different from the actual distribution results with decimal points

or directly applying the distribution method, the adjusted values can be input in the

reliability column after adjustment. For example, the reliability of equipment A is

determined to be 0.9625 hours according to the grading allocation method. After

comprehensive consideration, it is considered that the implementation technology of

the equipment is relatively mature, and the reliability of the equipment can be increased

(0.97), while the reliability of other equipment can be reduced relatively, so the

reliability can be input 0.97 after adjustment. At this point, the allocation result will be

0.97 instead of 0.9625.

Fixed failure rate: It is similar to fixed reliability.

Adjusted failure rate: It is similar to the reliability after adjustment.

Fixed MTBF: It is similar to fixed reliability.

Adjusted MTBF: It is similar to the reliability after adjustment.

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6 FMEA analysis

Failure Mode, Impact and Criticality Analysis (FMECA) is an engineering

technology for reliability and safety analysis. It is also an important work for

maintainability, supportability and testability design analysis. FMECA is an inductive

analysis method to analyze all possible failure modes and their possible impacts on the

system for each product/process in the system, and classify them according to the

severity of each failure mode, the difficulty of detection and the frequency of

occurrence. Using FMECA analysis method:

FMECA can be used for inspection and analysis of design drawings after the

completion of Engineering design.

Identify measures that can eliminate or reduce the chance of potential failure;

FMEA is generally required when new designs, new technologies, new

processes are adopted, or when existing designs or processes are modified, or

when existing designs or processes are used in new environments, sites or

applications.

6.1 Analytical method and standard predefinition

PosVim software supports FMEA standards such as GJB1391 and AIAG, and

supports function/hardware, process and software FMEA. PosVim software built-in

GJB1391, AIAG (automobile) industry FMEA standard template. It is assumed that

FMEA analysis is performed directly using the standard GJB1391 template built in

PosVim software.

6.2 FMEA analysis

6.2.1 Indenture levels selection

FMEA is a bottom-up reliability analysis method. In the process of FMEA analysis,

the choice of Indenture level and initial Indenture level will affect the depth of FMEA

analysis and the workload of FMEA analysis.

Suppose that the product structure tree of "XXX system" created in Section 2 (see

Section 2) is taken as an example, in which "XXX system" is chosen as the initial

Indenture level and the components of module A and module B as the lowest Indenture

level. FMEA analysis begins with the components of module A and module B.

Operation procedure:

Step 1:Make sure that you have open a project named "My First Project" and enter

the FMEA module. If the project and product structure tree are not created, they are

created in sections 1 and 2 respectively.

47

Step 2:Select the component "M01" under Module B.FMEA analysis begins with

components.

6.2.2 Failure Mode Information Setting

Step 3:Click on the top of the toolbar Add fault mode

Step 4:Enter product or function label in the "Product or Function Mark" column,

function description in the "Function" column, fault mode code in the "Identification

Number" column, fault mode directly in the "Mode" column, or select fault mode from

the drop-down selection box. As shown in the following figure.

Note: PosVim provides a fault mode library, which includes common mechanical

and electronic fault modes. You can choose the `Failure Mode of the `Basic Data Lib’

in the menu bar. Icon, click on, enter the maintenance and management of failure

mode.

Figure 6-1 Fault Mode Information Setting

6.2.3 Fault Affect Analysis

According to GJB1391 standard, fault affect includes three parts: local affect, high-

level affect and final affect.

Step 5:Input local affect and high level affect. Since the component M01 is the

object of current analysis and the upper layer is module B, the higher level affect refers

to the affect of module B. The final affect can only be selected at the initial Indenture

level "XXX System" level selected in section 6.2.1.This level does not belong to the

initial indenture level, so it cannot be input.

6.2.4 Qualitative analysis

According to GJB1391 standard, the information needed for qualitative analysis is

shown in the following figure. Other standards need to fill in different information,

according to specific standards.(Note: PosVim supports customize standards and

customize content and format requirements).

Figure 6-2 Qualitative Analysis

Select on Initial Indenture Level General five class

48

Step 6:Because the object of current analysis is component M01, which belongs to

the lowest indenture level, the severity class does not need to be filled in. The

corresponding information is filled in according to the actual situation in the probability

of failure mode, fault detection method, improvement measures and compensation

measures.

Note: PosVim will save these data as experience in the database every time it fills

in the fault detection method, improvement measures and compensation measures. The

next time it is used, it will automatically pop up the data items which contain the last

data, which can be selected for improving work efficiency.

6.2.5 Quantitative analysis

According to GJB1391 standard, the information needed to be filled in the

quantitative analysis column is shown in the following figure. Different standards need

to fill in different quantitative analysis content, can refer to the corresponding standards.

Figure 6-3 Quantitative Analysis

Step 7:In the quantitative analysis section, the following operations are performed:

7A:Firstly, data sources can be selected, such as reliability prediction, reliability

evaluation, reliability test and so on. By default, PosVim use the reliability predicted

failure rate data for the corresponding components.

7b:Then, the input frequency ratio is usually 0-1 in the section of "Failure Mode

Ratio";

7C: The affect probability can be filled according to empirical data or handbook.

7d:[Failure Rate] column is automatically acquired by default based on the

reliability predicted results, and you can also modify it manually.

7e:In the "Mission Time" column, fill in the mission time according to the actual

situation.

6.2.6 Affect Analysis of Intermediate level

Through the previous steps 1-7, the failure mode editing, qualitative analysis and

quantitative analysis of component M01 are completed. However, this is only to

complete the fault information editing and analysis of the lowest indenture level

component M01 itself, and further analysis of the affect of the fault mode on the upper

level and the higher level is needed until the initial indenture level "XXX system" is

reached. Methods of operation are:

Step 8:Click Module B in the "Product Structure Tree" list on the left of the

software main Window. At this time, you can see that in the failure mode, failure cause

column, the next layer node M01 information has been obtained.

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Figure 6-4 Failure Information of Inheritance Module B

Fault affect analysis of module B is carried out according to the following methods

(including inherited M01 fault information and new fault mode information of module

B itself). Here, inherited M01 fault information is selected for analysis, and no new

fault mode information of module B is added):

8A:Fill in the corresponding information in the columns of Product or Function

Mark, Function and Identification Number respectively.

Figure 6-5 Fault Information Input of Module B

8b: According to the method of 6.2.3, 6.2.4 and 6.2.5 subsections, the fault affect

analysis information, qualitative analysis information and quantitative analysis

information are added respectively. As shown in the following figure.

Figure 6-6 Qualitative and Quantitative Analysis Input of Module B

6.2.7 Fault Analysis at Initial Indenture Level

Through step 8, the result of fault affect analysis of middle level module B is

obtained. The failure affect of module B will be regarded as the failure mode of the

initial indenture level "XXX system", and the failure mode of module B will be

regarded as the failure reason of the initial indenture level "XXX system".

Implement the operation steps of the fault affect analysis of the initial indenture

level "XXX system" are:

Step 9:In the "Product Structure Tree" list on the left of the software main Window,

click on "XXX System". At this time, the system automatically inherits the information

of the next level (module B).

9A:Fill in the corresponding information in the columns of Product or Function

Mark, Function and Identification Number respectively.

Figure 6-7 Fault Information Input at Initial Indenture Level 9b:When filling in the local affect, because the level is the highest level (initial

indenture level), only the information of the column is needed. The information of the

high level affect and final affect need not be filled in, and is not editable.

50

When filling in the information of qualitative analysis column, in addition to filling

in the corresponding information of failure mode probability class, fault detection

method and design improvement measures according to the filling method of section

6.2.4, be sure to choose the "severity category".

According to the method of 6.2.5, fill in the information of each column for

quantitative analysis.

Fig. 6-8 qualitative analysis

6.2.8 Other information added

The fault information input of module B has been completed. In order to better

understand the function of PosVim, the fault affect analysis of module A is also carried

out here.

Step 10:According to the method of 6.2.1 to 6.2.5, a fault mode analysis record is

added to the component "2CE52" of module A.

Figure 6-9 Component Fault Information Input of Module A

Step 11:According to the method of 6.2.6, a fault analysis record (information

inherited from component "2CE52" fault) is added to module A.

Figure 6-10 Fault Information Input of Module A

Step 12:In accordance with the 6.2.7 method, add a record to the initial contract

level "XXX system", as shown in the following figure.

Figure 6-11 Fault Information Input at Initial Indenture Level

6.2.9 Analysis and calculation

After completing the above steps 1-12, the calculation can be carried out.

Step 13:Click on the toolbar. Icon, calculate.

At this point, the software Window will go to the calculation results view Window.

As shown in the following figure. You can change between different results by clicking

on the list of results on the left.

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Figure 6-12 FMEA analysis results

6.3 control plan &DVP

FMEA can be used to analyze and determine the impact level of different failure

modes, design improvement measures and coping methods. In order to implement these

improvement measures and coping methods, it is necessary to formulate corresponding

control plans, and carry out corresponding tests and verification. PosVim provides

control planning and DVP functions.

Methods of operation:

Step 1: Make sure you enter the project "My First Project" and the FMEA

analysis module.

Step 2:Click on the "Module B" node in the product structure tree on the left side

of the main Window, and then click on the one above the main Window. Icon,

you can pop up the control plan development window.

Step 3:In the control plan editing window, input the control plan information for

module B’s failure mode and cause, as shown in the following figure.

FMEA results list,

click to switch

52

Figure 6-13 Control Plan Editing

Step 4:When enterprises implement corresponding design improvements

according to the control plan, and carry out corresponding testing and testing, they need

to fill in the DVP form. Ensure that "Module B" is selected, click on the icon of the

toolbar, fill in the corresponding information in the pop-up Window as shown in the

following figure, and click save.

Figure 6-14 DVP editing

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6.4 Convert to Fault Relation Diagram

In addition to checking the impact relationship of faults at all levels of the product

by listing, PosVim also provides the function of graphically viewing the impact

relationship of faults at all levels. This is more intuitive and easier to perform fault logic

analysis for complex and large-scale systems. Methods of operation:

Step 1: Confirm that you are currently in the FMEA analysis module of My

First Project.

Step 2:In the list of product structure trees on the left side of the software main

Window, click and switch to the level of the fault diagram you want to view. For

example, click on "XXX System".

Step 3:In the Fault Analysis Record List in the middle of the main Window, right-

click on any Fault Analysis Record to select "Fault Relation Diagram" or click on the

toolbar. The icon opens all relevant failure mode relation

diagrams that cause the failure to occur. For example, click on the "No Signal " record,

and then right-click on the "Failure Diagram" to open the Window shown in the

following figure.

Figure 6-15 Fault Relation Diagram View

6.5 Convert to Fault Tree

In addition to graphically viewing fault relationships at all levels, PosVim also

provides the ability to intelligently convert FMEA data to Fault Tree data. Fault Tree is

automatically drawn by software, which greatly improves work efficiency. It also

guarantees data consistency and validity of FMEA and FTA.

Operation procedure:

54

Step 1: Confirm that you are currently in the FMEA analysis module of My

First Project.

Step 2:In the list of product structure trees on the left side of the software main

Window, click and switch to the highest level you want to convert into a fault tree, that

is, the level at which the top event is located. For example, click on "XXX System".

Step 3:In the Fault Analysis Record List in the middle of the main Window, right-

click on any Fault Analysis Record to select "Convert to Fault Tree" or click on the

toolbar Icon, you can create the fault tree with the fault as the top

event. For example, by clicking on the "Signal Processing Function Failure" record,

and then right-clicking on "Turn to Fault Tree", a pop-up window is displayed to

indicate whether or not to convert to Fault Tree. Click to confirm, you can open the

Window shown in the following figure.

Figure 6-16 Converts to Fault Tree

6.5 Fault Mode Library Management

To carry out FMEA work, the maintenance of fault mode library is very important.

PosVim provides a common library of failure modes for mechanical and electronic

components. These fault mode libraries can be added, deleted, edited and modified.

Specific measures:

6.5.1 Add fault mode

The steps for adding failure modes are as follows:

55

Step 1:Click Basic Data on the menu bar, and then click Icon. It can enter the

fault mode library management Window. The Window is divided into two parts. On

the left is the fault mode, and on the right is the fault mode attribute.

Figure 6-17 Fault Mode Library Management

Step 2:Click on the icon of the list of failure modes on the left Then enter a

"fatigue failure" failure mode in the input field.

Figure 6-18 Adding Failure Mode

6.5.2 Setting Failure Mode Properties

After adding the fault mode, the attributes of the fault mode can be edited. By

editing the fault mode attributes, we can specify which categories of products the fault

mode is mainly used for, so that when FMEA analysis is carried out, the software can

automatically screen out the alternative fault modes.

Operational steps (follow step 2 above):

Step 3:After adding the "Fatigue Failure" fault mode (remember to make the fault

mode input box non-editing state, otherwise it will remain in the state of input fault

mode, unable to add attributes. The method of operation is: click on any blank to switch

the input state, click on the toolbar above the list of fault mode attributes on the right,

and pop up the window to add fault mode attributes. The meanings and settings of each

column are shown in the following figure. Among them, "Product Category" column

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refers to the category of products that want to classify the failure mode into, "Predicted

Category" refers to the category of products that want to classify the failure mode into

the classification method in the prediction standard. The causes of failure, design

improvement, compensation measures and detection methods refer to the

corresponding causes and improvement measures of the failure mode. After setting up,

the software will fill in the information by default, without manual filling. If the

"Default" column is checked, the previous settings will take effect, otherwise they will

not take effect.

6.6 Computing configuration

The qualitative and quantitative analysis of FMEA involves many problems such

as the inheritance of fault information at different levels and the processing of different

fault information belonging to the same component. PosVim provides intelligent

functions to deal with these problems, such as ratio normalization, fault affect

inheritance and so on. Method of setting FMEA configuration information are:

Step 1:Click on the icon of the toolbar, pop-up in the qualitative analysis,

quantitative analysis, normalization processing Window, according to the need to

configure. As shown in figure 6-19~21.

Set use this

FM default

Set use this Cause

default

Set use this

Corrective default

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Figure 6-19 Qualitative Analysis Settings

Figure 6-20 Quantitative Analysis Settings

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Figure 6-21 Frequency Ratio Settings

6.7 Detection Method Library Management

PosVim provide the function of management common detection methods library.

The operation is:

Select "Basic Data Lib" from the menu bar and click Icon. Enter the detection

method library management Window.

click Add detection record.

6.8 Management of Fault Correction Action Lib

Through the management function of PosVim’s fault correction action library, we

can management the common fault correction action within the unit. The operation is:

Select "Basic Data Lib" in the menu bar and click on the icon 。Enter the

detection method library management Window.

click Add detection record.

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7 Fault tree analysis

7.1 create fault tree

Fault tree is an important and commonly used technical in the process of reliability

and safety analysis.

7.1.1 Creating Fault Tree Records

A project can create multiple fault trees. Project and fault tree are one-to-many

relationships. Therefore, we first need to create a fault tree analysis record. Operation

procedure:

Step 1: Make sure that you currently open a project called My First Project

and enter the Fault Tree Module(Click on the design analysis section of the menu

bar, and then click Icon.

Step 2:In the pop-up Fault Tree Management Window, Click Icon, new

fault tree record, name input "XXX system cannot work properly". As shown in the

following figure. Then click Open Fault Tree.

Figure 7-1 Fault Tree Record Creation

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7.1.2 Drawing Fault Tree Model

After opening the fault tree record, it enters the main Window of fault tree analysis.

The left Window is the product structure tree, followed by the fault tree structure list

(according to the fault tree drawing in the middle, real-time display of the structure

information of the fault tree), the middle is the main Window of the fault tree drawing,

and the right is the fault tree model library. As shown in the following figure.

Figure 7-2 Fault Tree Drawing Window

Assuming that the top event we have created is "XXX system cannot work

properly", the intermediate event that causes XXX system to not work properly is

module A failure or module B failure. The bottom event that causes module A failure

is each component failure, and the bottom event that causes module B failure is the

component simultaneous failure of module B. That is to say, the fault tree we want to

create includes three layers. The first layer is the top event "XXX system cannot work

properly", the middle layer is the failure of module A and module B, and the third layer

is the bottom event, that is, the failure of each component.

The steps to create the fault tree are as follows:

Step 3 (follow step 2 above)From the fault tree model library on the right, drag

and drop one and one or more doors to the drawing area, respectively. And double-click

on the new and door, or door, modify the door described as "A module function failure",

"B module function failure".

FTA structure

list

FTA Draw

Panel

Product

Structure tree FTA Model Lib

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Figure 7-3 Add and Gate, or Gate

Step 4: Drag three basic events from the model library and place them under the

"A module function failure" OR gate; similarly, drag three basic events under the "B

module function failure" AND gate. Double-click on the added basic events and modify

the names of each event according to the naming method shown in the figure below.

Figure 7-4 Adding Basic Events

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Figure 7-5 Modify Node Name

7.1.3 Calculating the probability of bottom/basic event

To obtain the probability of top events, it is necessary to set the probability of all

basic events/bottom events. The probability of occurrence of the underlying event/basic

event is as follows:

Step 5 (following step 4 above):Double-click the node named "2CW52" to pop

up the property box of the node. PosVim provides a variety of settings for event

occurrence probability, including direct input occurrence probability, distribution

calculation, etc. Distribution calculation mode is selected here. Exponential distribution

is selected for distribution type. Exposure time (or task time) is input for 24 hours, and

failure rate is input for 0.5.Click save. Similarly, other nodes are set in the same way.

So far, the fault tree has been constructed. It can be transferred to calculation.

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7.2 Fault Tree Computation and Analysis

7.2.1 Top event calculation

Step 1:Click on the icon on the toolbar to calculate the probability of the top event.

The calculation results are shown in the following figure. Including the calculation

results of top event occurrence probability, minimum cut set, event importance, number

statistics of cut sets of each order, probability statistics of occurrence of each order, etc.

Figure 7-6 Fault Tree Calculations (Top Events)

7.2.2 Computation of any other nodes

PosVim can not only calculate the occurrence probability of top events, but also

select any node of the fault tree to calculate the occurrence probability of events and

other indicators. Assuming that the probability of module A function failure is to be

calculated, the method of operation is as follows:

Return to the FTA draw window, select Node ‘Module A Function failure’ and

click Icon, we can calculate the probability of module A occurrence, and the

corresponding cut set, importance and other indicators.

Figure 7-7 Fault Tree Computation Results (Functional Failure Node of Module A)

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7.2.3 Set Cutset order

For complex fault trees, there are many cut sets, which can reach hundreds of

thousands or even tens of millions. At this point, if you want to filter out some higher-

order cutsets, you can use the toolbar’s Option, input the maximum order of

cut set, you can filter the higher order cut set.

7.3 Multifunctional/Common Cause Analysis

PosVim supports not only general fault analysis, but also fault tree analysis of

multi-functional nodes (special common cause) and common mode faults. It is assumed

that the RJ4501-1 fault event under the "module A function failure" gate event belongs

to the same component as the RJ4501 event under the "module B function failure" gate

event, that is, the component can complete the function of module A and module B. To

carry out multi-functional node fault analysis, the specific operations are as follows:

Step 1:Considering that the probability of occurrence of the three events under

module B is small, and it is with the gate, the result is very small. In order to better

compare the analysis results of whether multi-functional is set, the type of "module B

function failure" door is changed to "OR gate". The modification method is to double-

click the gate and then change the type to or gate.

Step 2:Click to calculate the probability of top events without multi-functional

nodes.

Figure 7-8 Computational results without multi-function nodes

Step 3: Return to the fault tree drawing Window, double-click the "RJ4501-1 fault"

event under the "module A function failure" gate event, in the pop-up property editing

box, Click Icon, pop-up multi-functional settings Window.

Step 4: Enter the name of the multifunctional group "RJ4501 Multifunction", then

double-click "RJ4501 Failure" under "Module B Function Failure" in the optional event

list. As shown in the following figure. Click save.

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Figure 7-9 Setting up Multifunctional Groups

At this time, you can see that the border of "RJ4501-1 Fault" and "RJ4501 Fault"

in the Fault Tree Drawing Window becomes red, indicating that the multi-function

setup is successful.

Figure 7-10 Fault Tree with Multifunctional Nodes

Step 5: click Icon for top event calculation. The probability of top

event occurrence is 3.31194E-05 (4.15191E-05 when no multi-function is set).

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Figure 7-11 Fault Tree Calculations with Multifunctional Nodes

7.4 Other operations and instructions

(1) PosVim fault tree analysis module can output fault tree graphics and various

calculation results.

(2) PosVim fault tree analysis module supports more than 10 types of events, such

as basic events and room events.

(3) PosVim fault tree analysis module supports more than 10 Boolean logic models

such as AND gate, OR gate, XOR gate.

(4) Support paging display, support loose layout and compact layout.

(5) All operations provide right-click menu operations.

The above functions can be experienced according to actual needs.

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8 Derating Analysis

8.1 Derating Standard Selection

PosVim supports GJB/Z 35, ECSS-Q-30-11-A, AS-4613 and other derating

standards, and can customize the derating criteria. The setting of the customized

derating criteria can be seen in section 8.5.

Suppose that GJB/Z 35 level II derating criterion is selected for module A

component derating design.

Step 1:Confirm that you have entered the project named "My First Project" and

entered the derating analysis module. Click Module A of the Product Structure Tree on

the left of the main Window.

Step 2:Click on the toolbar Select the level

II derating criterion of PosVim’s built-in GJB/Z 35 standard.

8.2 Setting of Derating Parameters

Step 3 (following the preceding steps):Select any component node in the middle

list of the main Window for derating design, such as the "2CW52" diode.

Step 4:Click on the top of the toolbar, or double-click on the "2CW52" diode node,

and pop up the parameter setting Window below the Window.

Step 5:Select the subclass "general diode" and then set the derating value of the

input current, voltage and other parameters as shown in the following figure.

Figure 8-1 Derating Parameter Setting Window

Step 6:Similar to other devices, the derating parameters are set one by one.

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8.3 Conformity Check of Derating

After setting the derating parameters of the components one by one, Click to get

the results of the conformity check of the derating. As shown in the following figure.

Figure 8-2 Conformity Check

8.4 report output

Click on the icon to output the derating design and inspection results.

8.5 Custom derating Criteria

In addition to PosVim’s built-in derating criteria, you can customize the derating

criteria.

Step 1:Click on the icon to pop up the custom guideline Window. Click on the

Custom Criteria Window Then enter "My Criteria" in the criteria name.

Step 2:It can input the required values of each criterion directly, or copy the

required values of GJB35 criterion directly, and then modify the parameters of each

criterion.

After modification, click the save icon.

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Figure 8-3 Custom Derating Criteria