20-03-2014, 03:19 PM
Modelling and Analysis of Composite Leaf Spring under the Static Load Condition by using FEA
Modelling and Analysis of Composite.pdf (Size: 155.24 KB / Downloads: 71)
Abstract
Leaf springs are one of the oldest suspension components
they are still frequently used, especially in commercial vehicles. The
past literature survey shows that leaf springs are designed as
generalized force elements where the position, velocity and orientation
of the axle mounting gives the reaction forces in the chassis attachment
positions. Another part has to be focused, is the automobile industry
has shown increased interest in the replacement of steel spring with
composite leaf spring due to high strength to weight ratio. Therefore,
analysis of the composite material becomes equally important to study
the behavior of Composite Leaf Spring. The objective of this paper is to
present modeling and analysis of composite mono leaf spring (GFRP)
and compare its results. Modelling is done using Pro-E (Wild Fire) 5.0
and Analysis is carried out by using ANSYS 10.0 software for better
understanding.
INTRODUCTION
Increasing competition and innovations in automobile
sector tends to modify the existing products or replacing
old products by new and advanced material products. A
suspension system of vehicle is also an area where these
innovations are carried out regularly. More efforts are
taken in order to increase the comfort of user. Appropriate
balance of comfort riding qualities and economy in
manufacturing of leaf spring becomes an obvious
necessity. To improve the suspension system many
modification have taken place over the time. Inventions of
parabolic leaf spring, use of composite materials for these
springs are some of these latest modifications in
suspension systems. This paper is mainly focused on the
implementation of composite materials by replacing steel
in conventional leaf springs of a suspension system.
Automobile-sector is showing an increased interest in the
area of composite material-leaf springs due to their high
strength to weight ratio. Therefore analysis of composite
material leaf springs has become essential in showing the
comparative results with conventional leaf springs.
EXPERIMENTAL PROCEDURE
In this paper, a comparative analysis of conventional
steel leaf spring is done with a virtual model of a
composite leaf spring under static load condition only.
Conventional leaf spring is first tested under static load
condition by using Hydraulic Static Load Test Rig.
Mounting of the leaf spring is done by keeping it in
inverted manner on the test bed. Two eye ends are held in
the clamping devices and load is applied from the top, at
the center of leaf spring. The spring is loaded from zero to
maximum load (i.e. 25 Kg) and again back to zero. The
vertical deflection of the spring is recorded in the load
interval of 5 Kg and specified as per the SOP prescribed
by SAE. To measure the load dial indicator is used which
is located beside the Test Rig and deflection is measured
by strain gauges located at the clamping of the test rig.
FINITE ELEMENT ANALYSIS COMPOSITE LEAF SPRING USING ANSYS 10.0
All the analysis for the composite leaf spring is done
by using ANSYS 10.0. For composite leaf spring the same
parameters are used that of conventional leaf spring. For
designing of composite leaf spring also the camber is
taken 136 mm. The constraint is given at the two eye-
rolled ends. One of the end is provided with translational
movement so as to adjust with the deflection. This eye end
is free to travel in longitudinal direction. This particular
motion will help leaf spring to get flattened when the load
is applied. Modelling is done without Roll Eye End
because their DOF are constrained in specific directions.
Produced results are very well compared with the realistic
leaf spring and it’s Experimental Procedure. The range of
loads is applied and results are analyzed. The maximum
principle stress is evaluated by software i.e. Von Mises
Stress and Maximum Deflection is also observed. It is
very much clear from the results produced by the ANSYS
for Conventional Steel Leaf Spring, that red colored area
indicated that eye end is the possible failure area for leaf
spring.
CONCLUSION
Under the same static load conditions deflection and
stresses of steel leaf spring and composite leaf spring are
found with the great difference. Deflection of Composite
leaf spring is less as compared to steel leaf spring with the
same loading condition.