Stress Analysis of a heavy duty vehicle chassis by using FEA

1. Seminar Presentation
on
Stress Analysis of a heavy duty vehicle chassis by
using FEA
Prepared by
SUNIL RATHOD (MM15M12)

2. • Contents
1. Introduction
2. Different types of automobile chassis
3. Typical heavy duty vehicle chassis
4. Methodology
5. Stress analysis of chassis
6. Results and Discussions
7. Conclusion
8. References

3. • Introduction
• Importance of chassis in vehicle
The chassis frame forms the backbone of a heavy vehicle, its principle function
is to safely carry the maximum load for all designed operating conditions.
• Design constraints for chassis
Stresses and Deflections are the design constraints for chassis.

4. • Different types of automobile chassis
• Ladder Chassis: This is considered to be one of the oldest forms of automotive
chassis and used by most of the SUVs till today. As its name ladder chassis resembles
a shape of a ladder having two longitudinal rails inter linked by several lateral and
cross braces.
• Monocoque Chassis: This is a one-piece structure that prescribes the overall shape of
a vehicle. This type of chassis is manufactured by welding floor pan and other pieces
together. Since this is cost effective and suitable for robotized production, most of the
vehicles today make use of steel plated monocoque chassis.
• Backbone Chassis: It has a rectangular tube like backbone, usually made up of glass
fibre that is used for joining front and rear axle together. This type of chassis is strong
and powerful enough to provide support smaller sports car. This is easy to make and
cost effective.

5. Typical heavy duty vehicle chassis

6. • Methodology

7. • Stress analysis of chassis
• Modeling
Full scale model of heavy vehicle chassis in CATIA

8. • Finite element analysis
The safety and the strength of chassis are important issues for the chassis
structure. To meet these requirements, it is essential to perform a static analysis on the
chassis. Static analysis was done using finite element method as it is an effective and
efficient approach. The analysis was performed based on following assumptions:-
1. The maximum design of payload for the chassis structure during application is
approximately 350kN.
2. The total load is distributed over the contact surface on chassis structure.
• Material Selection
The material for the chassis structure is ASTM Low Alloy Steel A 710 C (Class
3).
Modulus of
elasticity E (Gpa)
Poissons Ratio Yielding strength, 𝑆 𝑦 (MPa) Ultimate tensile strength, 𝑆 𝑢𝑡
(MPa)
210 0.3 550 620

9. • Meshing
When the material properties are given the geometry of wheel is imported from
CATIA software to ANSYS 12.1. After importing the model the meshing of the chassis is
carried out the meshing consist of 31559 elements and 32194 nodes.

10. • Loading
The force that has been imposed downward to the structure model. The load
is distributed uniformly along contact surface area. The total load of 350KN is applied
on the whole body of chassis uniformly as shown in fig.
Loading distribution on chassis

11. • Results & Discussions
As the analysis is carried out from the ANASYS 12.1 the results are generated.
There is some critical regions and areas where the stresses and deflections are maximum.
It is observed that the maximum deflection is pointed in situated in between BC1 and
BC2.
Stress distributions on chassis

12. As shown in above fig the value of equivalent von moises stresses variation the
maximum von moises stress acting on the chassis is 200.67 MPa
Deformations of Chassis

13. As the fig shows the deformation variations, the maximum deformation shown in
fig is 8.15mm and it is in the middle of the chassis between BC1 and BC2.
As the stresses and deformations are maximum there is some modifications
required for the structure of the chassis so that these stresses and deformations should be
minimized. As we increase in web height, thickness of frame can be reduced with this
relation we can decrease the stresses and deformations in chassis. Modification of cross
section of chassis frame member is made in three different cases. The inside fillet radius is
also increased by 2 times than the thickness of the cross section. Also the stresses on the
side member can be reduced by increasing the side member thickness locally. If the
thickness change is not possible, increasing the connection plate length may be a good
alternative. By using this technique we can reduce the value of stresses and deformation of
chassis.

14. • Conclusion
Hence in this seminar work I have studied the importance of chassis in
vehicle, various design constraints of chassis. The methodology that how to carry out
the finite element analysis of chassis and complete stress analysis procedure. The
complete chassis analysis is carried out by using ANSYS 12.1 and hence results
generated from this analysis shows the areas or regions of chassis which are critical
where maximum stresses acting, and regions where deformations are maximum are
find out and to reduce the stresses and deformations of chassis at critical point and to
increase the life of the chassis of heavy duty vehicle various design enhancement
solutions will be applied.

15. • References
1. A. Rahman, R., Tamin, M. N., Kurdi, O., 2008, “Stress Analysis of Heavy
Duty Truck Chassis using Finite Element Method,” Jurnal Mekanikal, No 26,
76-85.
2. Ingole, N. K., Bhope, D. V., 2011, “Stress analysis of tractor trailer chassis for
self weight reduction,” International Journal Of Engineering Science and
Technology (IJEST), Vol.3 No. 9.
3. Mohd Azizi Muhammad Nora, Helmi Rashida, Wan Mohd Faizul Wan
Mahyuddin, Mohd Azuan Mohd Azlanc, Jamaluddin Mahmud “Stress
Analysis of a Low Loader Chassis” International Symposium on Robotics and
Intelligent Sensors 2012 (IRIS 2012).
4. Sane, S. S., Jadhav, G., Anandraj, H., 1955, ” Stress Analysis of Light
Commercial Vehicle Chassis by FEM”,Piaggio Vehicle Pte.Ltd pune.Stress
Analysis of Heavy Duty Truck Chassis using Finite Element Method,” Phil.
Trans. Roy. Soc. London, vol. A247, pp. 529–551.
5. Roslan Abd Rahman, Mohd Nasir Tamin, Ojo Kurdi “Stress analysis of heavy
duty truck chassis as a preliminary data for its fatigue life prediction using
FEM” Jurnal Mekanikal December 2008, No. 26, 76 - 85

16. THANK YOU