laboration1_2009

8/3/2019 Laboration1_2009

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09-01-05 1(14)

Institutionen fr MaskinkonstruktionSystem och komponentdesignKjell Andersson

Laboration 1: Introduction to ADAMS modeling a piston

pump

The main purpose of this exercise in ADAMS is to improve the ability and understanding for how

ADAMS works and to illustrate the importance in analyzing and interpreting the results. This is

very important to emphasize that even if you are using very powerful programs you need to have

full control of the modeling as well as the analysis.

In this exercise we will study the behavior of a piston pump consisting of a piston, a flywheel and a

crankhandle, see figure 1. This pump will be used to pump liquids. The piston is gliding in a

cylinder (not shown in figure 1) and is sucking liquid from a house when the piston is moving out

from the cylinder. When the piston is moving into the cylinder it is pumping this liquid into another

house. The model you are building up in this exercise is shown in Figure 1 below

Figure 1. Piston Pump Isometric view

PUMP DATA

Wheel radius = 0.03 m Handle mass = 0.3 kg

Wheel thickness = 0.01 m Handle mass inertia:Ixx= 0.00001 kgm2-

,Iyy=Izz=0.0001 kgm2

Wheel density = 7800 kg/m3

Piston length=0.06 m

Handle length = 0.1 m Piston diameter = 0.04 m

Handle width = 0.015 m Piston massa=0.2 kg

Handle depth=0.01 m Piston mass inertia:Ixx 0.0001 kgm Iyy=Izz=0.0002 kgm

Table 1. Pump data


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KTH 2Institutionen fr MaskinkonstruktionSystem och komponentdesignKjell Andersson

The following tasks should be completed

1. The wheel radius should be parameterizedNote that all markers on the crank and the piston should be parameterized.

2. The flywheel is driven counter clockwise with a speed of 100 rpm.

3. Plot the piston position as a function of time (0-2 sec). Also plot the velocity as a function oftime.

4. Plot the resulting normal force on the piston (t= 0- 2 sec)

5. Plot the pump driving torque. Why is it varying?

6. Add a push or pull force on the piston, which is varying between + 1000N and -1000 Ndepending on in which direction the piston is moving.

7. Make a DESIGN_STUDY where the wheel radius can vary between 0.02 and 0.04m. Whatis the relation between radius and the driving torque?

Report

This exercise can be either be approved directly by the assistant at the scheduled event or sent as a

short report. If it is sent as a report it should contain plots from the tasks 4, 5 and 7 and answer the

questions in these tasks. The report should be sent in electronic form to [email protected],

[email protected] or [email protected]. This means that you continuously should select and save plot

curves as picture files during this exercise.

To start this exercise you need to do the following setup:

Starting Up ADAMS/View

From the ADAMS Product Menu, select ADAMS/View OK

Creating a Database from the Welcome dialog box

Create a new model Model Name: pistonpump (or: kolvpump ) OK

Setting up your work environment

Units

Setting Units Set the units: M, KG, N, SEC, DEG, H

Working Grid

F4 ( or: View Coordinate Window) , to let Coordinate Window ON

Settings Working Grid

Size: X=0.2, Y=0.1; Spacing = 0.005 (without units)

Show Working Grid = on; Set Location Global Origin OK


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Icons

Settings Icons New Size = 0.01; Visibility = On OK

Gravity

Check: Settings Gravity = ON, Y=-9.80665 OK

Building Piston Pump Model

Hints :

Start with creating points using theMain Toolbox, added to ground (Dont attach)in the

locations shown in Table 1.

Table 1. Points Coordinate Location

X Y Z

POINT_1 0.0 0.0 0.0

POINT_2 0.03 0.0 0.0

POINT_3 0.10 0.0 0.0

POINT_4 0.13 0.0 0.0

POINT_5 0.18 0.0 0.0

The Wheel

Create the Wheel part and its geometry (cylinder) using the design points

Note that you have to modify the orientation of the working grid and that then you have to

rename the part to wheel. The reorientation is done by utilizing the Working grid. :

SettingsWorking gridSet OrientationGlobal YZ

An additional hint could be to use the ISOMETRIC view for better visual control.

Once the Wheel part is created the working grid should be restored to its original setting i.e.

Global XY.

Place the cursor over wheel geometry Part: WheelModify Set up: Mass Properties

defined by =Geometry and Density, Density = 7800 Apply Show calculated inertia

OKThe Handle

Create the handle in a similar way as you did for the wheel, but use the link geometry.


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Modify the mass and inertia properties by using the modify option :Mass Properties defined

by =User Input Change to: Mass = 0.3, Ixx = 0.00001, Iyy = 0.0001 Izz = 0.0001 OK

The Piston

Create the piston as a cylinder with a start position at POINT_3 and dimensions as shown inTable 1.

Modify the mass and inertia properties in the same way as for the handle.

Defining the Joints

We need to define three revolute joints and one translational joint. Place these joints at the

locations defined by the design points.

We will use the following construction options:

1 Location, Normal To Grid (revolute joint between wheel and ground) use POINT_1

2 Bod-1 Loc, Normal To Grid (revolute joint between wheel and handle and revolute joint

between handle and piston) use POINT_2 and POINT_4

2 Bod-1 Loc, Pick Feature (translational joint between piston and cylinder (ground)) use

POINT_4..

Now it is time to save your model

File Save Database As File Name =pistonpump1.bin OK

Your model should now look like this in the FRONT view:

Figure 2.Piston pump front view


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Testing Your First Prototype

Adding motion on the Wheel

Main Tool boxMotion Rotational Joint Motion

Set up: Speed=600

Pick onjoint icon in the center of the Wheel

Simulating and Animating the Motion of the First Prototype

Main Tool box Simulation Set up: Kinematic, End Time=2.0, Steps=100 Pick

on Simulation Start tool

Main Tool box Animation Pick on Forward tool

Plot the Displacement of the Piston

Main Tool box Plotting, ADAMS Post Processor (PPT) will start!

Source: Objects Filter = body Object = +piston Characteristics =CM Position

Component = X Add Curves

On the SIDE TREEVIEW, Expand PAGE 1, select Plot 1.

In the Title text box, type:Piston Displacement

A title will appear in the SIDE TREEVIEW

Select A title Change the Font Size to 16

Select Vertical Axis Axis: vaxis

Labels=Length (meter), Font Size=14

Select: Numbers Font Size=12

Select Horizontal Axis Axis: haxis

Select Labels Label= Time (sec) , Font Size=14

Select Numbers Font Size=12

Your plot should look like figure 3 Piston Displacement


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Figure 3.Piston Displacement

Plot the Velocity of the Piston

On Main tool bar, Pick Create a new page

Your plot should look like figure 4 Piston Velocity:

Figure 4.Piston Velocity


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Plot the Normal Force of the Piston

Source: Objects Filter = constraint Object = +JOINT_3* Characteristics

=Element_Force Component = Y Add Curves

* Joint between Handle and Piston

Figure 5.Normal Force of Piston

Plot the Pump Driving Torque

Source: Objects Filter = constraint Object = +MOTION_1 Characteristics

=Element_Torque Component = Z Add Curves

Figure 6. Pump Driving Torque

File Close Plot Window


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Adding a Push and pull force on the Piston

Create a design point to connect the force to at the top of the piston (0.16,0.0,0.0)

(POINT_6)

Create a single component force, 2 bodies: Piston and ground (use POINT_5)

Create the force function. This function should give +- 1000 N depending on the moving

direction of the piston.

Hint: Use the SIGN and VX (or VR) function in the FUNCTION BUILDER.

SIGN(a1,a2) returns a1 dependent on the sign of a2.

VX(To,From;Along,Ref.Frame) returns the velocity in X-direction between two

markers in a given reference frame.

Simulating and Animating the Motion of the Prototype

Simulate the motion of the pump for 2.0 sec 100 steps.

Plot the Pull and Push Force of Piston

Your plot should look like the one below:

Figure 7.Pull and Push Force of Piston


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Plot the Pump Driving Torque

Your plot should look like the one below:

Figure 8.Pump Driving Torque

Refining Your Design

Creating Design Variables

Place the cursor over POINT_2 Point: POINT_2 Modify The Table Editor will

appear.

Select The Loc_X for POINT_2

Click in the input box at the top of the Table Editor Parameterize Create Design

Variable Real

The Design Variable is given the default name .pistonpump.DV_1 :

Change the name to .pistonpump.Radius by using the menu Edit Rename

Select The Loc_X for POINT_3

Click in the input box at the top of the Table Editor Parameterize Reference Design

Variable Radius OK

At the top of the Table Editor, change to (.pistonpump.Radius+0.07) Select The Loc_X for POINT_4


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Variable Radius OK

At the top of the Table Editor, change to (.pistonpump.Radius+0.1) Select The Loc_X for POINT_5


Variable Radius OK

At the top of the Table Editor, change to (.pistonpump.Radius+0.15) OK Select The Loc_X for POINT_6


Variable Radius OK

At the top of the Table Editor, change to (.pistonpump.Radius+0.13) OK Build Design Variable Modify Radius OK

Set up: Standard Value = 0.03, Units= length , Value Range by =Absolute Min and Max

Values, Min. Value= 0.02, Max. Value= 0.04 OK

Reviewing Design Variables

Tools Table Editor Select the Variables at the bottom of the table Editor

Filters Select: Delta Type=ON, Units=ON OK

Parameterizing other Geometries of your model

1. Parameterizing the Wheel

Place the cursor over WheelCylinder: CYLINDER_1Modify

Place the cursor in the Radius text box Parameterize Reference Design Variable

Radius OK

OK

2. Parameterizing the handle.cm Marker

Place the cursor over handle.cm MarkerMarker: cmModify

Change to Location = (.pistonpump.Radius+0.05), 0.0, 0.0 OK


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Running a Design Study

SimulateDesign Evaluation

Set up: Design Study=ON, Measure=ON, Maximum of = .pistonpump.MOTION_MEA_1,Design Variable .pistonpump.Radius, Default levels = 5

Settings: Display Chart Objective=ON, Chart design variables = ON, Save stripchart

curves=ON, Show tabular report = ON OK

Adjust the windows to see more Start

ADAMS displays Piston displacement plot (cm_MEA_1), Piston Velocity plot (cm_MEA_2),

Driving Torque plot (MOTION_MEA_1), Radius vs. Trial plot, MOTION_MEA_1 vs.

Radius plot, and a design study report.

Close the information window and the Design Evaluation box

Transfer the strip charts to full plot

Place the cursor over cm_MEA_1 chart Plot: scht1 Transfer to full plot

Your transferred plot should look like the one below:

Figure 9.Piston Displacements vs. Time

You can edit the plot, if you like.


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File Close Plot Window

In the same way, you can transfer the other charts, as shown next:

Figure 10.Piston Velocities vs. Time

Figure 11.Pump Driving Torque vs. Time


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Figure 12.Pump Driving Torque vs. Radius of the Wheel

Note: The title and the labels of the axis have been edited

Figure 13.Radius of the Wheel vs. Trial

Note: The title and the labels of the axis have been edited

All Done! To Save Your Work: Use a COMMAND FILE (.cmd). Note that your plots will NOT be

saved only the model.

Note that you first have to save the plots needed for the report.

Show your simulation plots to the lab assistant to get approved on the Lab before you exit

ADAMS.

File Export ADAMS/View command file, Exit ADAMS

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