Finite Element Analysis for stress calculations and safety
M.E. Seminar 3
Harshal R. Borole
Finite Element Analysis Techniques
for Stress Calculations and safety of
Dump Truck Frame
Nowadays, transportation industry plays a major role in
the economy of modern industrialized and developing
countries. The goods and materials carried through
heavy trucks are dramatically increasing.
There are many aspects to consider when designing a
heavy trucks chassis, including component packaging,
material selection, strength, stiffness and weight.
A dump truck frame is the most crucial part of the truck
that gives strength and stability to the vehicle under
A dumper frame – rigid to withstand shock, twist,
vibration and other stresses.
A well structured and properly built frame improves crash
worthiness, passenger safety and weight efficiency
Significance of the dumper frame
Dump truck is the variant on the basis of chassis, mainly
consisted of the chassis, power transmission device,
lifting mechanism, sub-frame, special-purpose box
and back flip axis etc.
The sub-frame plays the role of transitional frame to
enable the main frame support as much homogeneous
load as possible.
Sub-frame is connected to main frame through u-shape
bolts and thrust connection board, and is hinged
with cargo body through the back flip axis and
Frame is subjected to various loads at different
A 3D model of various mountings on the dump truck frame
during unloading process
Dump Truck Frame
A Dumper truck frame is a complex assembly which supports the loads
from lifting cylinder and carriage and also is subjected to harsh, uneven
The frame should have optimum strength along with adequate bending and
torsional stiffness to withstand such loads and conditions.
FEA study provides the basis for designing the frame since the frame is
modeled in various CAD softwares and analysis for strength and bending is
done by applying boundary conditions and different loads.
Different researchers have used different analysis techniques for optimizing
the design of frame for strength and weight reduction.
Statement of Purpose
Modeling and Analysis
Results & Discussions
Statement of Purpose
To Study various finite element analysis
techniques used for
a) Calculating different types of stresses induced
and deformation of dump truck frame
subjected to various loading conditions.
b) Determining the critical areas of stress
concentration for a fail-safe and lightweight
The dumper frame is very critical in designing as there
are various factors to be considered while
a) Dumper frame at rest – Static loads supported by the
b) Dumper is moving - different sets of vibration modes of
c) Dumper is unloading – Dynamic loads and torque
For the first case, FEA is done on different sections of
the frame for determining the critical areas of stress
For second case, FEA is done on the whole frame
which is excited to different low frequencies which are
close to potential exciting sources like oscillations of
Finite Element Analysis
Based on the conditions, dumper truck frame is
analyzed for stress optimization by following
1) FEA for Static load.
2) Modal analysis for determining various mode
shapes and predicting different dynamic responses
3) Dynamic analysis of the frame structure during
initial state of cylinder lifting and critical state of
4) FEA by reinforcement technique for stress
Static Load Analysis
For this analysis, a standard dump truck with following
specifications was used and the frame model was
prepared in CATIA and finally analyzed with the help of
Gross Vehicle Weight (GVW): 25000kg.
Gross Combined Weight (GVW + Payload): 26200kg.
Frame: Ladder type heavy duty frame, depth- 285mm,
width- 65mm, frame width- 903mm.
The magnitude of pressure on the upper side of chassis
is determined by dividing it into 3 parts.
1) P1= F/A = 128511 / 65 * 10-6 * 6670 = 290321.9248 N/m2
2) P2 = 1200 * 9.81 / 65 * 10-6 * 1400 = 129362.6374 N/m2
3) P3 = 1200 *9.81 / 65 * 10-6 * 740 = 244740.1247 N/m2
Modal Analysis Of Truck Frame
Frame forms the backbone of the dump truck, when the
truck travels along the road, the truck chassis is excited
by dynamic forces caused by the road roughness,
engine, transmission etc.
After constructing a finite element model for the frame,
modal analysis can be used a tool to determine natural
frequencies and mode shapes.
Sr. no. Mode no. Frequency Displacement
1 1 16.894 Twisting about X-axis
2 2 25.537 Bending about Y-axis
3 3 27.427 Deformation about X-axis and bending
4 4 28.746 Twisting about X-axis and Bending
5 5 33.971 Twisting about X-axis
6 6 34.316 Deformation about X-axis and bending
7 7 36.564 Deformation about X-axis and Y-axis
8 8 46.316 Deformation about X-axis
FEA Of Frame During Unloading
The dump truck loads the goods by large construction
machinery, so the phenomenon of biased loading goods
In the unloading process, because of the biased load of
goods, the stresses induced in the frame are worse.
So force analysis should be carried out to detect critical
areas of stress concentration.
The unloading of goods condition consists of two parts –
1) Initial state of oil cylinder lifting
2) Critical state of goods declining
Initial State Of Oil Cylinder Lifting
In this state, because the static friction torque of each
hinge point in lifting system is large and the lifting Angle
of oil cylinder is the most adverse, the lifting force should
be the largest.
Meanwhile, the reaction force oil cylinder against to the
secondary frame is also the largest.
Critical State Of Goods Declining
In this state, the cargo body has left away from the
surface of the frame when goods are about to decline,
so all the weight is carried by the back flip axis and the
FEA By Reinforcement Technique
For Stress Optimization
In this, finite element analysis is performed on a truck
frame and critical areas of stress concentration are
determined in terms of von-mises stresses.
Reinforcement is the technique of adding cover plates on
external side members at highly stressed regions to
improve the strength and life of the frame.
A CAD model of the frame is prepared in CATIA V5R19 and
structural analysis is done in ANSYS workbench.
The meshed model has applied boundary conditions and
load is applied on side rails.
The load is applied on complete span of the side rail as
uniformly distributed load.
Von mises stress distribution in original frame
Von mises stress distribution in reinforced frame
Total deformation of original frame
Total deformation of reinforced frame
Maximum principal stress in original frame
Maximum principal stress in reinforced frame
Type Main frame Reinforced frame
Pressure (MPa) 0.07395 0.07148
Max Principal Stress 132.79 128.89
Table no. 2 Structural analysis results for original frame and
From the above table and analysis, we can conclude that –
Maximum stress and maximum displacement in reinforced
frame is lower than original frame.
Reinforced technique decreases deformation of frame by 4.7
% and stress by 31.42 %
In order to obtain same deformation or stress level, we can
apply additional load of 600 kg on the frame.
So reinforced frame increases the load carrying capacity with
same factor of safety as of original frame.
Jing-ping Si, Guo-sheng Wang, Xian-long Ding,
‘Analysis of Dump Truck Unloading Condition
Based on ANSYS’, Advanced Materials Research Vol.
Z. Chen et. Al.,‘The Lightweight Design of a Dump
Truck Frame based on Dynamic Responses’, 18th
International Conference on Automation & Computing,
Pratik Sarda, Prof. Baskar P. et. al., ‘Stress
Optimization of Frame with Reinforcement
Technique by FEA’, International Journal of
Engineering Research & Technology (IJERT) Vol. 3
Issue 5 
Monika S. Agrawal, Md. Razik ‘Finite Element
Analysis of Truck Chassis’, International Journal of
Engineering Research & Technology (IJERT) 
Nouby M. Ghazaly, ‘Applications of Finite Element
Stress Analysis of Heavy Truck Chassis: Survey
and Recent Development’, Journal of Mechanical
Design and Vibration, 
Patel Vijaykumar V, Prof. R. I. Patel, ‘Structural
Analysis of Automotive Chassis Frame and Design
Modification for Weight Reduction’, International
Journal of Engineering Research & Technology (IJERT)
Vol. 1 Issue 3