Stress Analysis of Truck Chassis Using FEA - BE Project - ALL

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:

i

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






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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1

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.

2

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”.

3

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.

4

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.

14

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.

15

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

17

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

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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.

28

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.

29

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.

31

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

32

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


Fig 5.7 Stress Distribution on Nominal loading In Joint 3

48


49



50


51



52


53



54


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

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Stress Analysis of Truck Chassis Using FEA - BE Project - ALL