31

ISSN 2348-7852 (Print) | ISSN 2348-7860 (Online) ijre.org

IJRE | Vol. 03 No. 04 | April 2016

DESIGN AND ANALYSIS OF CHASSIS FRAME Author(s):

1Anurag,

1Amrendra Kumar Singh,

1Akash Tripathi,

1Aditya Pratap Tiwari,

1Nitish upadhyay,

2Shyam Bihari Lal

Student1,Asst. Prof.

2, Dept. of Mechanical Engineering, Buddha Institute of Technology, Gorakhpur, U.P. India

Abstract– Truck chassis is the structural backbone of any

vehicle. The main function of the truck chassis is to carry

the goods and payload placed upon it. The chassis frame

has to bear the stresses developed and deformation occurs

in it and that should be within a limit. This paper presents

the study of the stress developed in chassis as well as

deformation of chassis frame. The stress and deformation

has been calculated for the chassis frame and the analysis

has been done for the validation on the chassis frame. The

model of the chassis has been developed in Creo (Pro-E)

2.0 and static structural analysis has been done in ANSYS

WORKBENCH 15.0.

Keywords:Truck Chassis, Static Structural Analysis, ANSYS

WORKBENCH 15.0,Deformation,Ladder Frame.

I.INTRODUCTION

Automobile chassis usually refers to the lower part of

the vehicle including the tires, engine, frame, driveline and

suspension. Out of these, the frame gives necessary support to

the vehicle components placed on it. Also the frame should be

so strong to resist impact load, twist, vibrations and other

bending stresses. The chassis frame consists of side rails

attached with a number of cross members.

Along with the strength, an important consideration

in the chassis design is to increase the bending stiffness and

torsion stiffness. Proper torsional stiffness is required to have

good handling characteristics. Commonly the chassis are

designed on the basis of strength and stiffness. In the

conventional design procedure the design is based on the

strength and is then focused to increase the stiffness of the

chassis, with very small consideration to the weight of the

chassis. This design procedure involves the adding of

structural cross member to the existing chassis to improve its

torsional stiffness. As a result, weight of the chassis increases.

This increase in weight of the chassis fuel efficiency is

reduced and increases the overall cost due to extra material.

The design of the chassis with proper stiffness and strength is

necessary.

The design of a vehicle structure is of fundamental

importance to the overall vehicle performance. The vehicle

structure plays an important role in the reliability of the

vehicle. Generally, truck is a heavy motor vehicle which is

designed for carrying the attached weights, such as the engine,

transmission and suspension as well as the passengers and

payload. The major focus in the truck manufacturing industries

is to design vehicles with more payload capacity. Using high

strength steels than the conventional ones are possible with

corresponding increase in payload capacity.

The chassis of truck which is the main part of the

vehicle that combines the main truck component systems such

as the axles, suspension, power train, cab and trailer etc.,

asshown in Figure-1, is one of the possible candidates for

substantial weight reduction.

Automotive designers need to have complete

understanding of various stresses prevalent in different areas

of the chassis component. During the conceptual design stage,

when changes to the design is easy to implement and have less

impact on overall project cost, the weight and structural

characteristics are mostly unknown since detailed and overall

vehicle information is not available at the early stage .

The vehicle design starts up with conceptual studies

to define size, number and location of undriven and drive

axles, type of suspension, engine power, transmission, tire size

and axle reduction ratio, cab size and auxiliary equipment. The

selected configuration has to be more precise and accurate for

the considered transportation tasks and should match the

existing production line. In general, there are two approaches

to analyze truck chassis: one is stress analysis to predict the

weak points and the other is fatigue analysis to predict life

cycle of the frame.

This overview selectively and briefly discusses some

of the recent and current developments of the stress analysis of

truck chassis. A number of analytical, numerical and

experimental methods are kept in mind for the stress analysis

of the heavy duty truck frames. Conclusion of the stress

analysis in the vehicle chassis has been reported in literature.

Finally, the scope of future work has been discussed after

concluding on the obtained results.

Figure-1 3D Modelling of Chassis Frame

Side Member

Cross Member

Connecting

Plate

Rivet

32

ISSN 2348-7852 (Print) | ISSN 2348-7860 (Online) ijre.org

IJRE | Vol. 03 No. 04 | April 2016

II. METHODOLOGY

This study has been dealt with two parts. First part of this

study involves modeling of chassis frame and analysis of

stresses and displacement under actual load conditions. CAD

models of chassis frame were developed in 3D modeling

software, such as Creo (Pro-E) 2.0 (Pro-E). The stress analysis

and stiffness of the models are then obtained in ANSYS

WORKBENCH 15.0. While the second part is shape

optimization as weight or mass reduction purpose utilizing

solid. Weight of the proposed design of chassis frame is then

being compared to the current component that have been used

for the previous existing chassis model [4].

Approach of this study is shown in Fig - 2.

Figure-2 Design Methodology Flowchart

III. MODELING OF EXISTING CHASSIS FRAME

The model of chassis which has been used currently

as per the dimension is created in Creo (Pro-E) 2.0 as shown

in Figure 3.The model is then saved in IGES format which

can be directly imported into ANSYS WORKBENCH 15.0 .

Figure 3 shows the imported model in ANSYS

WORKBENCH 15.0.

Figure-3 Actual C-beams chassis

IV. DESIGN OF CHASSIS FRAME

(A) Calculation of Load

i) Axial Loads

There are two axial load acting on the chassis frame such as

tensile load and compressive load [5]. The stress due to this

load can be find out using the following formulae,

Tensile Load (Pt) = Tensile stress x Area

Compressive Load (Pc) = Compressive stress x Area

ii) Bending Load

This load acts on the chassis frame due to the weight of the

vehicle and this tends to bend the chassis frame downward

away from the centerline [5]. Total inertia bending load is

given by,

Bending Load (Fb) = 𝝆𝑨𝒕𝑳 𝒔𝒊𝒏(𝜽+∅)

𝟐 N

(B) Calculation of Stresses

i) Stress Due to Axial Loads

The force of resistance per unit area, offered by a body

against deformation is known as stress.

This is given by,

Stress (σ) = 𝑷

𝑨

ii) Stress due to Inertia bending force

Inertia bending load sets up a stress which would be tensile on

one side of the chassis and compressive on another side and

that these stress change sign each half revolution [5].The

bending moment at any section „x‟ m from the small end is

given by,

M = 𝑥

𝑎 1 −

𝑥2

𝐿2

The stress is calculated by,

σb =𝑀

𝑍

Initiates and evaluate current design

Redraw and analyze current design

Design Modeling

Creo (Pro-e),

FEA Analysis

ANSYS WORKBENCH

Evaluat

e

Design

Further analysis and optimization

Further Evaluate Design or Optimized Design

Final Design and stop

yes

no

33

ISSN 2348-7852 (Print) | ISSN 2348-7860 (Online) ijre.org

IJRE | Vol. 03 No. 04 | April 2016

V. MESHED MODEL OF CHASSIS

Meshing of the chassis frame model is done in ANSYS

WORKBENCH 15.0. The meshed model is shown in fig. 4

Figure-4Zoomed View of Meshed model of Chassis frame

NUMBER OF NODES 301873

NUMBER OF ELEMENTS 141884

Table-1 Nodes and Elements of Model

V. MATERIAL OF MODEL

For the frame geometry of chassis commonly steel

and its alloys are used. For the frame models, variety of

materials, composite materials and different kind of alloys

like steel, Carbon/Epoxy, E-Glass/Epoxy, S-Glass/Epoxy, etc.

can be used. In the present study HSLA Steel is used and its

properties are as given below.

Material HSLA Steel

Modulus of Elasticity E 2.6 x 105N/mm

2

Poisson’s Ratio 0.3

Tensile Yield Strength 310 Mpa

Tensile Ultimate Strength 448 Mpa

Density 7800 kg/m3

Thermal Conductivity 43w/m-k

Table-2 Material properties of chassis

CHEMICAL COMPOSITION

Quantity %Weight (max)

Carbon 0.16

Silicon 0.15-0.35

Manganese 0.8-1.3

Phosphorous 0.025

Sulphur 0.025

Niobium 0.02-0.05

Table-3 Chemical Composition of HSLA Steel

VI. ANALYSIS

(A) LOADS IN A STATIC ANALYSIS

Static analysis is used to determine the force in structure ,

displacement, stress, strain or component cause by load that do

not induced significant inertia and damping effect[5].

There are following type of load apply in static analysis

which are given below.

Externally applied forces.

Steady-state inertial forces.

Figure-5 Loading Condition of Chassis Frame

(B) STATIC ANALYSIS A static analysis calculate the effect of steady loading

condition on the structure, while ignoring inertia and damping

effect such as those caused by the varying load and time-

varying load can be approximated as static equivalent load[5].

Figure-6 Total deformation (HSLA Steel)

Figure-7 Von Mises stress (HSLA Steel)

34

ISSN 2348-7852 (Print) | ISSN 2348-7860 (Online) ijre.org

IJRE | Vol. 03 No. 04 | April 2016

Figure-8 Maximum Principal Stress (HSLA Steel)

Figure-9 Maximum Shear Stress (HSLA Steel)

(C) PROCEDURE FOR STATIC ANALYSIS

There are three main steps involve in static analysis.

i) Build the model

ii) Apply load and obtain solution

iii) Review the result

.

VII. RESULT

Previous model of the chassis frame which is made

up of steel (mild steel) having yield strength 250 Mpa and

mass is about 597.67 kg. We have selected HSLA Steel for

analysis having yield strength 310 Mpa and mass is about

593.87 kg. The percentage mass reduction of the chassis frame

was found to be 0.63%. The optimized value of the result is

given below.

Parameters Initial Material

(Mild Steel)

Final Material

(HSLA Steel)

Total Deformation 0.0088mm 0.0084mm

Maximum

Principal Stress

44140 Pa 44574 Pa

MASS

Initial Material

(Mild Steel)

Final Material

(HSLA Steel)

% Reduction

597.67 kg 593.87 kg 0.63%

Table-4Comparison of Chassis Frame

VII. CONCLUSION

The chassis frame component has been modelled

using Creo (Pro-E) 2.0 and analyzed in ANSYS

WORKBENCH 15.0. The various parameters such as Nodal

displacement, stress distribution are completely analyzed and

studied. The study shows that the area where the stress

concentration is maximum due to applied load and the portions

that has to be considered in the design of chassis frame in

order to avoid frequent failures to improve its reliability.

Stress analysis of chassis has been done to predict the

weak points. Several state of the art papers and even books on

chassis stress analysis have been presented in the recent

years.This study makes a case for further investigation on the

design of truck chassis using Ansys software.

REFERENCES

[1] International Journal of Advances in Engineering &

Technology, Nov., 2014.©IJAET ISSN: 22311963

[2]Dumber et al.,International Journal of Advanced

Engineering Research and Studies E-ISSN2249–8974

[3] International Journal of Emerging Trends & Technology in

Computer Science (IJETTCS) Website:www.ijettcs.org Email:

editor@ijettcs.org, editorijettcs@gmail.com Volume 2, Issue

2, March – April 2013 ISSN 2278-6856

[4] Vishal Chaudhary, Deepak Nidgalkar and Dinesh

Chennappa "Case study of process Automation:

ChassisStiffness", Altair CAE Users Conference 2005.

[5] Murali M.R. Krishna, “Chassis Cross-Member Design

Using Shape Optimization”, International Congressand

Exposition Detroit, Michigan. February 23-26, 1998.

[6] PSG Design Data Book for Standard Data-M/s Kalaikathir

Achchagam, Coimbatore2004

[7] Machine design by R S Khurmi, S. Chand and Co. Ltd.,

New delhi-2001.

[8] Stress analysis of a truck chassis with riveted joints by

Cicek Karaoglu*, DEU Faculty of Engineering, 35100

Bornova, Izmir, Turkey ,Finite Elements in Analysis and

Design 38 (2002) 1115–1130

[9] A text book of “DESIGN OF MACHINE ELEMENT” by

V.B Bhandari, Tata McGraw Hill Education Pvt. Ltd.

[10] A text book of “Theory of machines” by R.S. KHURMI

and J.K GUPTA, S.CHAND, EURASIA PUBLISHING

HOUSE (PVT.) LTD.