stress analysis of truck chassis using fea - be project - all
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PROJECT REPORT On
STRESS ANALYSIS ON TRUCK CHASSIS USING FEA
Submitted in partial fulfillment for the award of the degree
Of
BACHELOR OF TECHNOLOGY
in
MECHANICAL ENGINEERING
By
T. DEEPAK SARATHY (10203036) V. DILIPAN (10203040)
G. KARTHIK (10203063)
under the guidance of
Mr. S. PRABHU, M.E., (Senior Lecturer, School of Mechanical Engineering)
& Dr. M. SATHYA PRASAD,
DGM (Advance Engg.,) , Ashok Leyland, Chennai
FACULTY OF ENGINEERING AND TECHNOLOGY
SRM UNIVERSITY
(under section 3 of UGC Act,1956) SRM Nagar, Kattankulathur – 603 203
Kancheepuram Dist
April 2007
BONAFIDE CERTIFICATE
Certified that this project report “STRESS ANALYSIS ON TRUCK
CHASSIS USING FEA ” is the bonafide work of
“T. DEEPAK SARATHY (10203036), V. DILIPAN (10203040) and
G. KARTHIK (10203063)” who carried out the project work under my
supervision.
DEAN INTERNAL GUIDE
School of Mechanical Engineering Date:
INTERNAL EXAMINER EXTERNAL
EXAMINER
Date:
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ACKNOWLEDGEMENT
In the course of our project, we are indebted to so many people who
have contributed for making this project a great success. We would like to
express our heartfelt gratitude to our Dean Dr.Krishnan (School of
mechanical Engineering SRMIST) for giving us this opportunity to do this
project.
We express our sincere gratitude to M/S ASHOK LEYLAND Private
Limited for encouraging us to carry on this assignment. We owe our thanks
to Dr.M.Sathyaprasad, DGM (Advance Engg.,) for his guidance
throughout this project.
We would like to thank our internal guide Mr.Prabhu (Senior
Lecturer SRMIST) for his support, which helped us to complete this project
successfully.
We would like to express our sense of gratitude to all our college
faculties for their timely help and valuable guidance in the course of the
project.
We are indebted to our parents for having supported us in all our
endeavors…..
ABSTRACT
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In this project, stress analysis of a truck chassis was performed
through FEA. The truck chassis was modeled using PRO/E and the
commercial finite element package ANSYS was used to solve the problem.
The joint area with the max stress was identified using the above software
package. In order to achieve a reduction in the magnitude of stress near the
riveted joints area, local plates were introduced .
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LIST OF CONTENTS CHAPTER NO. TITLE PAGE NO ACKNOWLEDGEMENT i ABSTRACT ii LIST OF FIGURES vi LIST OF TABLES vii LIST OF GRAPHS vii 1. INTRODUCTION 1
1.1 Importance of connections 1
1.2 Stress Analysis 1
1.3 Finite Element Analysis 2
2. SOFTWARE PACKAGES 4
2.1 PRO/E 4
2.1.1 Sketcher Modes 5
2.1.2 Modeling tools 8
2.1.3 Assembly Constraints 9
2.1.4 Constrain orientation assumptions 11
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2.1.5 Common exchange specifications 12
2.1.6 Benefits 12
2.2 ANSYS 13
2.2.1 General Analysis Procedure 14
2.2.2 Structural Analysis 16
2.2.2.1 Types of Structural Analysis 17
2.2.2.2 Steps in a Structural Analysis 17
2.2.3 Benefits 21
3. TRUCK AND CHASSIS 23
3.1 Different parts of a truck 23
3.2 Function of chassis 25
3.3 Parts of chassis 27
3.4 Riveting Operation in a truck chassis 28
3.5 Loads acting on a chassis 30
3.6 Material Data of the chassis 32
4. MODELING AND MESHING 33
4.1 PRO/E Model 33
4.2 Meshed Model 34
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5. STRESS ANALYSIS 36
5.1 Load Applied on the model 36
5.2 Stress Distribution across joint areas 38
5.2.1 Stress distribution across joint 1 38
5.2.2 Stress distribution across joint 2 40
5.2.3 Stress distribution across joint 3 42
5.2.4 Stress distribution across joint 4 44
5.2.5 Stress distribution across joint 5 46
5.2.6 Stress distribution across joint 6 48
6. RESULTS AND DISCUSSION 50
7. CONCLUSION 53
REFERENCES
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LIST OF FIGURES
FIGURE NO. TITLE
PAGE NO
3.1 Different Parts of a truck 23 3.2 Parts of a truck chassis frame 27 3.3 Installation of a riveter 28 3.4 Riveting Operations on a truck chassis 29 3.5 Model 1613H 31 4.1 Pro/E model of chassis 33 4.2 Meshed model of chassis 34 4.3 Zoomed view of meshed model 35 5.1 Load Applied on the chassis 36 5.2 Zoomed view of the applied load 37 5.3 Stress distribution at joint 1 for nominal loading 38 5.4 Stress distribution at joint 1 for maximum loading 39 5.5 Stress distribution at joint 2 for nominal loading 40 5.6 Stress distribution at joint 2 for maximum loading 41 5.7 Stress distribution at joint 3 for nominal loading 42 5.8 Stress distribution at joint 3 for maximum loading 43 5.9 Stress distribution at joint 4 for nominal loading 44 5.10 Stress distribution at joint 4 for maximum loading 45 5.11 Stress distribution at joint 5 for nominal loading 46
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5.12 Stress distribution at joint 5 for maximum loading 47 5.13 Stress distribution at joint 6 for nominal loading 48 5.14 Stress distribution at joint 6 for maximum loading 49 6.1 Gap at Joint 5 51 6.2 Introduction of local plates at joint 5 52
LIST OF TABLES FIGURE NO. TITLE PAGE NO
3.1 Material data 32 6.1 Stress distribution across various joint areas 50
LIST OF GRAPHS
FIGURE NO. TITLE
PAGE NO
6.1 Stress distribution across joint areas for nominal loading condition 50 6.2 Stress distribution across joint areas for maximum loading condition 51
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CHAPTER 1
INTRODUCTION
1.1 IMPORTANCE OF JOINTS:
Many engineering structures and machines consist of
components suitably connected through carefully designed joints. In metallic
materials, these joints may take a number of different forms, as for example
welded joints, bolted joints and riveted joints. In general such joints are
subjected to complex stress states under loading since the joints are quite
complex in nature there would manifest severe stress discontinuities that
cannot be calculated using closed form solutions it is in such situations finite
element analysis lends itself as an indispensable tool. Good design of
connections is a mixture of stress analysis and experience of the behavior of
actual joints; this is particularly true of connections subjected to repeated
loads.
1.2 STRESS ANALYSIS:
Stress analysis is an engineering discipline that determines the
stress and strain in materials and structures subjected to static or dynamic
forces or loads. The aim of the analysis is usually to determine whether the
element or collection of elements, usually referred to a structure, can safely
withstand the specified forces. This is achieved when the determined stress
from the applied force(s) is less than the allowable strength, or fatigue
strength the material is known to be able to withstand, though ordinarily a
safety factor is applied in design.
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A key part of analysis involves determining the type of loads
acting on a structure, including tension, compression, shear, torsion,
bending, or combinations thereof such loads. Sometimes the term stress
analysis is applied to mathematical or computational methods applied to
structures that do not yet exist, such as a proposed aerodynamic structure, or
to large structures such as a building, a machine, a reactor vessel or a piping
system.
A stress analysis can also be made by actually applying the
force(s) to an existing element or structure and then determining the
resulting stress using sensors, but in this case the process would more
properly be known as testing (destructive or non-destructive). In this case
special equipment, such as a wind tunnel, or various hydraulic mechanisms,
or simply weights is used to apply the static or dynamic loading.
When forces are applied, or expected to be applied, repeatedly,
nearly all materials will rupture or fail at a lower stress than they would
otherwise. The analysis to determine stresses under these dynamically forced
conditions is termed fatigue analysis and is most often applied to
aerodynamic structural systems.
1.3 FEA
Finite Element Analysis is a technique to simulate loading
conditions on a design and determine the design’s response to those
conditions. The design is modeled using discrete building blocks called
elements. Each element has exact equations that describe how it responds to
a certain load. The “sum of the response of all elements in the model gives
the total response of the design”.
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The finite element model, which has a finite number of
unknowns, can only approximate the response of the physical system, which
has infinite unknowns. It depends entirely on what we are simulation and the
tools we use for the simulation. Guidelines are provided throughout this
volume to perform various types of analysis.
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WHY IS FEA NEEDED? :-
• To reduce the amount of prototype testing
• Computer simulation allows multiple “what-if” scenarios to be
tested quickly and effectively.
• To simulate designs that are not suitable for prototype testing
Example: Surgical implants, such as an artificial knee.
• The bottom line:
- Cost and Time savings.
- Create more reliable, better-quality and competitive designs.
CHAPTER 2
SOFTWARE PACKAGES
2.1 PRO – E
Pro/ENGINEER is the world’s leading 3D product
development solution, which is developed by PTC-Parametric Technology
Corporation a US based Company. This software enables designers and
engineers to bring better products to the market faster. It takes care of the
entire product development process, from creative concept through detailed
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product definition to serviceability. Pro/ENGINEER delivers measurable
value to manufacturing companies of all sizes and in all industries.
With industry leading productivity tools such as promoting best
practices in modeling techniques and ensuring compliance with your
industry and company standards, Pro/ENGINEER is the gold standard in 3D
CAD design. Integrated Pro/ENGINEER CAD/CAM/CAE solutions allow
us to design faster than ever, while maximizing innovation and quality to
ultimately create industry-winning products. And, because the applications
are fully integrated, you can develop everything from concept to
manufacturing within one application, with the confidence of knowing every
design change will automatically be propagated to all downstream
deliverables.
Pro/ENGINEER is the solid modeler-it develops models as
solids, allowing us to work in a three-dimensional environment. In
Pro/ENGINEER, the models have volumes and surfaces areas. We can
calculate mass properties from the geometry we create. As a solid modeling
tool, Pro/ENGINEER is
Feature Based
Parametric
Associative
FEATURE BASED: Pro/ENGINEER is feature based. Geometry is
composed of a series of easily understandable features. A feature is a
smallest building block in a part model.
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PARAMETRIC: Pro/ENGINEER is a parametric (i.e.) it’s driven by
parameters or variable dimensions. The geometry can be easily
changed by modifying the dimensions. Here features are interrelated.
Modifications of single feature propagate changes in other features as
well, thus preserving design intent.
ASSOCIATIVE: Pro/ENGINEER models are often combination of
various parts, assemblies, drawings and other objects.
Pro/ENGINEER makes all these entities fully associative. That means
if we make changes in certain level that will propagate in all levels.
Now we shall explain the commands used to design our part
from sketcher mode to the assembly
2.1.1 SKETCHER MODES COMMANDS AND ITS
INTRODUCTION:
Any geometry involving complex definitions and individual
shapes requires sketch. Sketches are required for all types of protrusion and
cuts. The word sketch is basically meant for sections, because the sketch
represents the cross-section of any feature. Sketch is a two dimensional
geometry, only when combined with other elements (example depth) it
becomes a three dimensional feature. Now we shall see the various
commands used in the sketcher mode in detail.
LINE: Line command allows us to draw a line by specifying the end
points. The Intent manager allows us to choose the options such as 2
points, parallel, perpendicular, tangent, 2 tangent, pnt/tangent horizontal,
vertical.
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PARALLEL: Draws a line parallel to a selected linear entity. Select an
existing entity for the direction of the line and then pick the start points
and the end points
PERPENDICULAR: Draws a line perpendicular to a selected linear
entity. Select the existing entity for the direction of the line and then pick
the start points and end points.
TANGENT: This option facilitates to draw a line tangent from an entity
to the next point. The selected entity should be an arc, ellipse, conic and
spline .It prompts for end point, and then the line will be generated
tangential to those entities.
PNT/TANGENT: The line is drawn from a point to a tangent of an
entity (Circle, arc, ellipse etc).Pick a point and selects the entity to which
the line must be tangent.
HORIZONTAL: Using this option we can generate horizontal lines. The
end point of the line is taken as the start point of vertical chained vertical
line.
VERTICAL: Using this option we can generate vertical lines. The end
point of the line is taken as the start point of vertical chained vertical line.
CENTERLINE: Centerlines are used to define the axis of the revolution
of a revolved feature, to define a line of symmetry within a section. It can
be used as construction lines. Centerlines have infinite length and are not
used to crate feature geometry.
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RECTANGLE: By picking up one vertex with the left mouse button and
drag the rectangle to the desired size we can generate rectangle. The four
lines of the rectangle are independent. We can handle them (trim, align
and so forth) individually.
CIRCLE: Creates a circle by picking the center point and point that lies
on the circumference of the circle. The intent manager allows drawing
circle in different ways.
3 TANGENT: Creates a circle tangent to the selected three reference
entities.
FILLET: Creates a circle tangent to the selected two reference entities.
3 POINT: Creates a circle by picking any three circumferential points.
ELLIPSE: Creates a ellipse by clicking the center of the ellipse and drag
the other point to complete the ellipse.
FILLET: Creates a rounded intersection between any two entities. The
size and location of the fillet depends on the pick locations. When a fillet
is inserted between two entities, the system automatically divides two
entities at the fillet tangency points. If we add the fillet between two non-
parallel lines, the lines are automatically trimmed to the fillet.
AXIS POINT: Using axis point option from the sketch menu to create
an axis that is normal to the sketching plane. The depth of the axis is
determined by the geometry of the feature and is similar to an axis of a
cylindrical hole.
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DIMENSIONING: We can add our own dimensions to create the
desired dimensioning scheme. User dimensions are considered as
‘STRONG’ dimensions by the system. As we sketch a section the system
automatically dimensions the geometry .These dimensions are called
weak dimensions. They appear in grey.Linear dimensioning is carried out
to dimension a line or an entity.
DIAMETER: To create a diameter dimension for arc or a circle the arc
or the circle is double clicked and the middle mouse button to place the
dimension.
TRIM: Using this command we can trim two entities. Here we can click
any two entities on the portion of the entity that we want to keep.
Pro/ENGINEER trims two entities together.
MIRROR: Mirror command is used to mirror the sketcher geometry
about a sketched centerline. For example, we can create half of the
section and then mirror it. Before mirroring make sure the sketch
contains the centerline. Here we can select an entity or multiple entities
to mirror.
2.1.2 MODELING TOOLS:
Protrusion feature: Protrusion is the method of adding a solid material to the
model that is, it can add material in a void or on an existing solid. Types of
protrusion feature are:
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1. Extrude-creates a solid feature by extruding a section normal to the
section plane.
2. Revolve-creates a solid feature by revolving a section about an axis.
3. Sweep-creates a solid feature by sweeping a section about trajectory.
4. Blend-creates a solid feature by blending various cross section at various
levels.
EXTRUSION: Extrusion is the method of defining a volume by
extruding the sketched cross section along an axis normal to the
section plane. To define Extrusion first we should define the sketch
plane in which we want to draw the cross section, and then we have to
define the direction of Extrusion and the amount of Extrusion by
various options.
ONE SIDE: Adds the material in one side of the cross-section
only.
BOTH SIDE: Adds the material on both sides of the cross-
section.
BLIND: By this method we can directly specify the depth of
Extrusion as a numerical value.
2 SIDE BLIND: This method is available for extrusion in both
sides.
CUT FEATURE:
Cut is a method of removing solid material from the model.
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CUT EXTRUDE: Removes a volume by extruding its section a
normal to the section plane.
SWEPT BLEND:A swept blend requires a trajectory and multiple
sections. To define the origin trajectory of the swept blend, we can
either sketch a curve or select a chain of datum curves or edges.
PATTERN:
A pattern allows us to make parametric copies of an existing
feature. Because a pattern is parametrically controlled, we can modify it by
changing pattern parameters, such as number of instance, spacing between
instances and leader dimensions. All instances are by nature duplicates of
the leader, changing a leader dimension updates all instances and vice versa.
The pattern command only allows we to select a single feature, we can
pattern several feature as if they were single feature by arranging them in a
local group.
2.1.3 ASSEMBLY CONSTRAINTS:
We can position one component with respect to the other
components using assembly constraints. A placement constraint specifies the
relative position of a pair of references. The followings are the placement
provided by Pro/ENGINEER. And we are explaining the main constrains
that are used to design the model:
Mate
Align
Insert
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Coord Sys
Tangent
Pnt On Line
Pnt OnSrf
Edge On Srf
Default
Fix
MATE:
We can use the mate constraint to position two planar surfaces
or datum planes parallel and their normal pointing opposite to each other. If
datum planes are mated their yellow sides face each other.
ALIGN:
We can use the Align constraint to make two planes coplanar
(coincident and facing the same direction) two axes coaxial, or two points
coincident. We can align revolved surface or edges. The yellow sides face
the same direction instead of facing each other as when mated.
INSERT:
We can use the Insert constraint to insert one revolved surface
into another revolved surface, making their respective axes coaxial. This
constraint is useful when axes are unavailable or inconvenient for selection.
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ORIENT:
We can use the Orient constraint to orient two planar surfaces
to be parallel facing the same direction. It does not specify the offset.
COORD SYS:
We can use the Coord Sys constraint to place a component in
an assembly by aligning its coordinate system with a coordinate system in
the assembly
PNT ON LINE:
We can use the Pnt On Line constraint to control the contact of
an edge, axis, or datum curve with a point.
EDGE ON SRF:
We can use in this constraint to control the contact of a surface
with a planar edge.
FIX:
We can use the Fix constraint to fix the current location of the
component that was moved or packaged.
2.1.4 CONSTRAINT ORIENTATION ASSUMPTIONS:
After defining an align constraint between the axes of the hole
and the bolt and ,for example, a mate constraint between the bottom face of
the bolt and the top face of the plate, the system assumes at hired constraint.
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The constraint controls rotation about the axes, thereby fully constraining the
components.
With the Pro/ENGINEER assumptions disabled, we can
package drag a component out of a previously assumed position. And have it
remain in the new position. The component automatically snaps back to the
assumed position if Assumption check box
MIRROR:DRAWING>tools>mirror
We can use this command to create copies of draft and entities,
unattached symbols, and unattached notes by mirroring them about to a draft
line
Select a draft line about which to mirror the entities. The
system creates a copy of the selected entities as mirror image of the source
entities.
TRIM:DRAWING>tools>trim
We can use this command to lengthen or shorten draft
geometry. The system uses the geometry definition to find its intersection
with the bounding entity. When we choose this command, PRO-E displays
the trim menu.
We can export solid model information about parts and
assemblies in the following formats STL(Stereo lithography apparatus)
RENDER, inventor, VRML, OpteraVis, Xpatch, MEDUSA, Catiafacets
(also referred to as catia mock-up), and 3-D paint. STL is used for a variety
of puposes,the primary one is rapid prototyping.
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2.1.5 COMMON EXCHANGE SPECIFICATIONS:
STEP FILES:
Through STEP, we can exchange complete product definition
between heterogeneous computer-aided design, engineering, and
manufacturing systems.
The step format is organized as a series of documents(in STEP
terminology, referred to as parts)with each part published separately
application protocols (Aps)which reference generic parts, are produced to
meet specific data exchange requirements for a particular application.
IGES:
When exporting assembly files to IGES, the System generates
an IGES file with the suffix _asm appended to the name of the file. This is to
prevent overwriting a part with an assembly file of the same name. When an
assembly is exported to IGES , the structure and the output contents are
specified. Select all levels which exports an assembly file with external
references to all components as well as all the components to IGES files. It
creates components parts and subassemblies with their respective geometry
and external references. This option supports all levels of hierarchy.
2.1.6 CAPABILITIES & BENEFITS:
Complete 3D modeling capabilities.
Maximum production efficiency through automated generation of
associative tooling design, assembly instructions, and machine
code
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Ability to simulate and analyze virtual prototypes to improve
product performance and optimize product design
Ability to share digital product data seamlessly among all
appropriate team members
Compatibility with myriad CAD tools — including associative
data exchange — and industry standard data formats
2.2 ABOUT ANSYS
ANSYS is a complete FEA simulation software package developed by
ANSYS Inc-USA. It is used by engineers worldwide in virtually all fields of
engineering.
• Structural
• Thermal
• Fluid (CFD, Acoustics, and other fluid analyses)
• Low-and High-Frequency Electromagnetics.
Introduction to General Analysis Procedure in ANSYS
Ansys is a high-performance finite element pre- and
postprocessor for popular finite element solvers – allowing engineers to
analyze product design performance in a highly interactive and visual
environment. Ansys user-interface is easy to learn and supports many CAD
geometry and finite element model files – increasing interoperability and
efficiency. Advanced functionality within ansys allows users to efficiently
mesh high fidelity models. This functionality includes user defined quality
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criteria and controls, morphing technology to update existing meshes to new
design proposals, and automatic mid-surface generation for complex designs
with of varying wall thicknesses. Automated tetra-meshing and hexa-
meshing minimizes meshing time while batch meshing enables large scale
meshing of parts with no model clean up and minimal user input.
• FEA & ANSYS
Finite Element analysis, the core of Computer Aided
Engineering dictates the modern mechanical industry and plays a decisive
role in cost cutting technology.
ANSYS the leading FEA simulation software, with its robust
capabilities guides the Engineers to arrive at a perfect design solution.
A PARTIAL LIST OF INDUSTRIES IN WHICH ANSYS IS USED:
• Aerospace
• Automotive
• Biomedical
• Bridges & Buildings
• Electronics & Appliances
• Heavy Equipment & Machinery
• MEMS – Micro Electromechanical Systems
• Sporting Goods
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2.2.1 GENERAL ANALYSIS PROCEDURE
This explains the general analysis procedure to be used to solve a simulation.
Regardless of the physics of the problem, the same general procedure can be
followed.
Every analysis involves four main steps:
• Preliminary Decisions
• Preprocessing
• Solution
• Post processing
PREPROCESSING
CREATE THE SOLID MODEL A typical solid model
is defined by volumes, areas, lines and keypoints.
CREATE THE FEA MODEL Meshing is the process
used to “fill” the solid model with nodes and elements,
i.e., to create the FEA model.
DEFINE MATERIAL Every analysis requires some
material property input: Young’s modulus EX for
structural elements, thermal conductivity KXX for
thermal elements, etc.
There are two ways to define material properties
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Material library
Individual properties
Solution
Define Loads
There are five categories of loads
• DOF Constraints
• Concentrated Loads
• Surface Loads
Loads distributed over a surface, such as pressure or convections.
• Body Loads
• Inertia Loads
ANSYS POSTPROCESSORS: POST1, the General Postprocessor, to
review a single set of results over the entire model. POST26, the Time-
History Postprocessor, to review results at selected points in the model over
time. Mainly used for transient and nonlinear analysis.
2.2.2 STRUCTURAL ANALYSIS:
Structural analysis is probably the most common application of
the finite element method. The term structural (or structure) implies not only
civil engineering structures such as bridges and buildings, but also naval,
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aeronautical, and mechanical structures such as ship hulls, aircraft bodies,
and machine housings, as well as mechanical components such as pistons,
machine parts, and tools.
The primary unknowns (nodal degrees of freedom) calculated
in a structural analysis are displacements. Other quantities, such as strains,
stresses, and reaction forces, are then derived from the nodal displacements.
Structural analysis is available in the following ANSYS programs.
ANSYS/Multiphysics
ANSYS/Mechanical
ANSYS/Structural
ANSYS/Professional
2.2.2.1 TYPES OF STRUCTURAL ANALYSIS
STATIC ANALYSIS
Used to determine displacements, stresses, etc. under static
loading conditions which includes both linear and nonlinear characteristics.
Nonlinearities can include plasticity, stress stiffening, large deflection, large
strain, hyper elasticity, contact surfaces, and creep.
2.2.2.2 STEPS IN A STRUCTURAL ANALYSIS
CREATION OF GEOMETRY: This can either be created within
ANSYS or imported.
The following points are to be carefully considered in model creation.
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Sufficiently model the stiffness of the structure.
Add details to avoid stress singularities (e.g. filets).
Exclude details not in region of interest (e.g. exclude small holes) .
Add details to improve boundary conditions (e.g. apply pressure to an
area rather than using concentrated load).
ELEMENT TYPE
Most ANSYS element types are structural elements,
ranging from simple spars and beams to more complex layered shells and
large strain solids. The nodal DOF’s may include: UX, UY, UZ, ROTX,
ROTY, and ROTZ.
Most types of structural analyses can use any of these elements.
Type 2d solid 3d solid 3d shell Line elements
Linear Plane 42 Solid 45
Solid 185
Shell 63
Shell 181
Beam 3
Beam 4
Beam 188
Quadratic Plane82
Plane2
Solid95
Solid92
NA NA
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Solid186
MATERIAL PROPERTIES
In certain ID or 2D problems, the second or third parameters or
both are specified through the Real Constants or Section properties
command. For e.g. in a beam problem, we can specify the length in the
model, but the cross section parameters are specified in the Sections
properties, Similarly, thickness for a shell element is specified in the Real
Constants dialog box.
To define real constants: Choose Preprocessor Real Constants from the
main menu. In the Real Constants dialog box, click Add. Then enter the
specified real constant value of the material selected.
DEFINE LOADS
Structural loading conditions can be:
DOF Constraints - Regions of the model where displacements
are known.
Concentrated Forces - External forces that can be simplified
as a point load.
Pressures - Surfaces where forces on an area are known.
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DISPLACEMENT CONSTRAINTS
This is used to specify where the model is fixed (zero
displacement locations). It can also be non-zero, to simulate a known
deflection.
To apply displacement constraints:
Choose Solution Define Loads Apply Structural
Displacement
Preferences
Preprocessor
Solution
Analysis Type
Define Loads
Settings
Apply
Structural
Displacement
On Lines
On Areas
On Keypoints
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On Nodes
On Node components
Symmetry B.C.
Antisymm B.C.
Pick the desired entities in the graphics window. Then choose the constraint
direction. Value defaults to zero.
CONCENTRATED FORCES
Force is a point load, applied on a node or keypoint, specifying
the force magnitude and direction of force.
Choose Solution Define Loads Apply Structural
Force/Moment from Main Menu.
When we delete solid model loads, ANSYS also automatically
deletes all corresponding finite element loads.
REVIEWING RESULTS
Gives a quick indication of whether the loads were applied in
the correct direction.Legal column shows the maximum displacement,
DMX.We can also animate the deformation.To plot the deformed shape
Choose General Postproc Plot Results Deformed Shape
Choose Plot Ctrls Animate Deformed shape
STRESSES:
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The following stresses are typically available for a 3-D solid model.
Component Stresses - SX, SY, SZ, SXY, SXZ (global
Cartesian direction by default.
Principal Stresses - S1, S2, S3, SEQV (von Misses),
SINT (Stress intensity).
Best viewed as contour plots, which allow us to quickly locate
"hot spots" or trouble regions.
Nodal solution: Stresses are averaged at the nodes, showing smooth,
continuous contours.
Element solution: No averaging, resulting in discontinuous contours.
TO PLOT STRESS CONTOURS:
General Postproc * Plot Results * Contour Plot Nodal Solu
General Postproc * Plot Results * Contour Plot * Element
Solu
We can also animate stress contours :
Plot Ctrls > Animate> Deformed Results...
2.2.3 BENEFITS:
Reduce time and engineering analysis cost through high-
performance finite element modeling and post-processing
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The industry's broadest and most comprehensive CAD and
CAE solver direct interface support
Reduce overhead costs of maintaining multiple pre- and post-
processing tools, minimize "new user" learning curves, and
increase staff efficiency with a powerful, intuitive, consistent
finite element analysis environment
Open-architecture design and customization functionality
allows to Ansys fit seamlessly in any environment
Reduce redundancy and model development costs through the
direct use of CAD geometry and legacy finite element models
Simplify the modeling process for complex geometry through
high-speed, high-quality automeshing, hexa-meshing and
tetrameshing
Dramatically increase end-user modeling efficiency by
eliminating the need to perform manual geometry clean up and
meshing with Batch Mesher technology
27
CHAPTER 3
TRUCK AND CHASSIS
3.1 DIFFERENT PARTS OF A TRUCK:
Fig3.1 Different parts of a truck
The different parts of a truck are:
1.Body
2.Axle
3.Chassis frame
4.Transmission
5.Engine
6. Cab.
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BODY:
Specific body structures such as flatbeds, standard vans, box
vans, dump-truck deep-beds, tankers, concrete mixers etc. permit the
economical and efficient transportation of a wide variety of goods and
materials. Connection between body and load-bearing chassis frame is
effected in part by means of auxiliary frames.
AXLE:
An axle is a central shaft for a rotating wheel or gear. In some
cases the axle may be fixed in position with a bearing or bushing sitting
inside the hole in the wheel or gear to allow the wheel or gear to rotate
around the axle. In other cases the wheel or gear may be fixed to the axle,
with bearings or bushings provided at the mounting points where the axle is
supported.
CHASSIS FRAME:
The chassis frame is the commercial vehicle’s actual load
bearing element. It is designed as a ladder type frame, consisting of side and
cross members. The conventional chassis frame, which is made of pressed
steel members, can be considered structurally as grillages. The chassis frame
includes cross-members located at critical stress points along the side
members. To provide a rigid, box-like structure, the cross-members secure
the two main rails in a parallel position. The cross-members are usually
attached to the side members by connection plates.
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TRANSMISSION:
Small trucks use the same type of transmission as almost all
cars which have either an automatic transmission or a manual transmission
with synchronizers. Bigger trucks often use manual transmissions without
synchronizers which are lighter weight although some synchronized
transmissions have been used in larger trucks. Transmissions without
synchronizers require either double clutching for each shift, (which can lead
to repetitive motion injuries,) or a technique known colloquially as
“floating,” a method of shifting which doesn’t use the clutch, except for
starts and stops.
ENGINE:
An engine is something that produces an effect from a given
input.
CAB:
The cab is an enclosed space where the driver is seated. There
are a variety of cab designs available depending on the vehicle concept. In
delivery vehicles and vans, low, convenient entrances are an advantage,
whereas in long-distance transport space and comfort are more important.
The type of cab configurations are cab-over-engine (COE) and cab-behind-
engine.
3.2 FUNCTION OF CHASSIS FRAME:
The chassis frame is the commercial vehicle’s actual load
bearing element. It is designed as a ladder type frame, consisting of side and
30
cross members. The choice of profiles decides the level of torsional stiffness.
Torsionally flexible frames are preferred in medium and heavy duty trucks
because they enable the suspension to comply better with uneven terrain.
Torsionally stiff frames are more suitable for smaller delivery vehicles and
vans.
Critical points in the chassis-frame design are the side-member
and the cross-member junctions. Special gusset plates or pressed cross-
member sections form a broad connection basis. These junctions are riveted,
bolted and welded.
The conventional chassis frame, which is made of pressed steel
members, can be considered structurally as grillages. The chassis frame
includes cross-members located at critical stress points along the side
members. To provide a rigid, box-like structure, the cross-members secure
the two main rails in a parallel position. The cross-members are usually
attached to the side members by connection plates. The joint is riveted or
bolted in trucks and is welded in trailers. When rivets are used, the holes in
the chassis frame are drilled approximately 1/16 in larger than the diameter
of the rivet. The rivets are then heated to an incandescent red and driven
home by hydraulic or air pressure. The hot rivets conform to the shape of the
hole and tighten upon cooling. An advantage of this connection is that it
increases the chassis flexibility. Therefore, high stresses are prevented in
critical area. The side- and cross-members are usually open-sectioned,
because they are cheap and easily attached with rivets.
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3.3 PARTS OF A TRUCK CHASSIS FRAME:
Connecting Plate
Cross Member
Side Member
Fig 3.2 Parts of a truck chassis frame
The different parts of a conventional truck chassis frame are:
1.Side members
2.Cross members
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3. Gusset plates or connection plates.
3.4 RIVETING OPERATION ON TRUCK CHASSIS:
A monorail shall be provided above the operating places and
the trolley compiled with the balancer shall be hung down from the
monorail. The generator shall be installed at the place where it will be free
from troubles and operation. The high pressure steel pipe shall be arranged
from the generator to the center upper portion of operating position, then
high pressure hose shall be connected between the pipe end and riveter the
piping shall be fixed at near by columns or supporting beams, with clamps
for protection against vibration the hose shall be fixed with spring bands in
order to flexure; however its fixing shall not affect the operation of riveter.
33
Fig 3.3 Installation of a Riveter
34
Fig 3.4 Riveting Operations on a truck chassis
ADVANTAGES OF COLD RIVETING:
1. The heating equipment and its operator are unnecessary.
Handing of rivet is easy, accordingly.
2. In case of riveting, if its rivet is longer in length or irregular
in hole diameter, the rivet will be fully expanded in the hole,
then the rivet head will be formed; therefore it makes no
looseness in cooling, sealing or against vibrations.
3. Caulking is not necessary because no extra tension is added
to the rivet.
35
3.5 LOADS ON CHASSIS FRAME :
All vehicles are subjected to both static and dynamic loads.
Dynamic loads result from inertia forces arising from driving on uneven
surfaces. Static loads are as follows : Static load of stationary vehicle,
braking, acceleration, cornering, torsion, maximum load on front axle,
maximum load on rear axle.
Loads acting in the frame cause bending or twisting of the side
and the cross-members. Symmetric loads acting in the vertical direction
predominantly cause bending in the side members. Vertical loads
additionally arise from lateral forces acting parallel to the frame’s plane, e.g.
during cornering. Loads acting in the plane of frame cause bending of the
side members and of the cross-members.
o SPECIFICATIONS OF 1613H
36
Fig 3.5 Model-1613H
3.6 MATERIAL DATA:
Table 3.1 Material Data
37
MATERIAL
HSLA Steel to Ashok Leyland Standard
for ALMDV Models Having Young’s
Modulus (E) 2.6*105 N/mm2 and Poisson’s
Ratio (ν) 0.3.
CHEMICAL
COMPOSITION
Carbon
Silicon
Manganese
Phosphorus
Sulphur
Niobium
0.16% max
0.15-0.35% max
0.8-1.3% max
0.025% max
0.025% max
0.02-0.05% max
CHAPTER 4
MODELLING AND MESHING OF TRUCK CHASSIS 4.1 PRO-E MODEL OF THE DESIGNED CHASSIS
38
Fig 4.1 Pro-E Model of Chassis
4.2 MESHED MODEL OF THE CHASSIS:
39
Fig 4.2 Meshed Chassis
40
Fig 4.3 Zoomed View of Meshed Model
CHAPTER 5
STRESS ANALYSIS 5.1 Load Applied On the Model:
41
Fig 5.1 Load Applied
42
Fig 5.2 Zoomed View of Applied load
5.2 STRESS DISTRIBUTION AT JOINT AREAS 5.2.1 Stress distribution across joint 1
43
Fig 5.3 Nominal Loading at Joint 1
44
Fig 5.4 Stresses at Maximum Load Condition on Joint 1
45
5.2.2 Stress distribution across joint 2
Fig 5.5 Stress Distribution On Nominal loading In Joint 2
46
Fig 5.6 Stress Distribution at Joint 2 on Maximum Load condition
47
5.2.3 Stress distribution across joint 3
Fig 5.7 Stress Distribution on Nominal loading In Joint 3
48
Fig 5.8 Stress Distribution at Joint 3 on Maximum Load condition
49
5.2.4 Stress distribution across joint 4
Fig 5.9 Stress Distribution on Nominal loading In Joint 4
50
Fig 5.10 Stress Distribution at Joint 4 on Maximum Load condition
51
5.2.5 Stress distribution across joint 5
Fig 5.11 Stress Distribution on Nominal loading In Joint 5
52
Fig 5.12 Stress Distribution at Joint 5 on Maximum Load condition
53
5.2.6 Stress distribution across joint 6
Fig 5.13 Stress Distribution on Nominal loading In Joint 6
54
Fig 5.14 Stress Distribution at Joint 6 on Maximum Load condition
55
CHAPTER 6
RESULTS AND DISCUSSION From the analysis performed the maximum stress was found to
be at joint area 5 the respective graphs shown below clearly signifies that at
the maximum loading condition the stress was found to be 151.98 N/mm.
Table 6.1: Stress distribution across the joints
Jo
e
ng
t
ng (
int ar
Stress a
Stress a
a t
number
a
i
Maximum loadi
Nominal lo
d
(
56
56
2
)
N
2
)
N/mm
/mm
1 4 151
1
2 43
133
3 43
133
4 40
117
5 60
152
6 4 144
5
Graph 6.1 Stress distributions at Nominal Loading
41 4045
0
10
20
30
40
60
70
1 2 3 4 5 6
JOINT NUMBER
STR
ESS
(N/M
M^2
)
43 43
60
50
Nominal loading
57
Graph 6.2 Stress distributions at Maximum loading
The reason for maximum stress in the joint area was due to the
presence of gap found between the gusset plate (Connecting plate) and the
side member as shown below.
introduced as shown below.
151133 133
117
152144
0
20
40
60
80
100
120
140
160
1 2 3 4 5 6
JOINT NUMBER
STR
ESS
(N/M
M^2
)
Maximum Loading
Fig 6.1 Gap at Joint 5
SUGGESTION
To reduce the stress at the joint area 5 local plates can be
58
Fig 6.2 Introduction of local plates at joint 5
CHAPTER 7
CONCLUSION
maximum stress acting
on tes
can to reduce the stress at the joint area. Furthermore, the
str found to be considerably lower than the
material can
From the stress analysis performed, the
the truck chassis was found to be at joint 5(151N/mm2 ) and local pla
be introduced
ess value of 151N/mm2 was
allowable stress of the material (288 N/mm2). Thus, a suitable
59
be selected and consequently a reduction in the overall weight of the chassis
an be achieved.
REFERENCES:
• Stress analysis of a truck chassis with riveted joints
Finite Elements in Analysis and Design, Volume 38, Issue 12,
October 2002,
Pages 1115-1130
Ciçek Karaolu and N. Sefa Kuralay
• Automotive handbook, BOSCH, 5th Edition, Page 730-736
• Strength of Materials and Structures, 2nd Edition, Page 55-91, J. Case
and A. H. Chilver
• Stress intensity factor and load transfer analysis of a cracked riveted
lap joint
Materials & Design, Volume 28, Issue 4, 2007, Pages 1263-1270
• Stress intensity factors in riveted steel beams
Engineering Failure Analysis, Volume 11, Issue 5, October 2004,
Pages 777-787
J. Moreno and A. Valiente
c
60