08-12-2012, 01:46 PM
Minimization of Stress of a Parabolic Leaf Spring by Simulated Annealing Algorithm
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ABSTRACT
A leaf spring is simple form of spring, generally used for the suspension in automotives. Earlier it was like a slender arc-shaped having length of a spring steel of rectangular cross-section. In this paper analysis is done for leaf spring whose thickness varies from the center to the outer side following a parabolic pattern. The development of a parabolic tapered leaf spring enabled the springs to become lighter, but also provided a much improved ride to the vehicle through a reduction on interleaf friction. To move further, authors take an opportunity to perform a Finite element analysis (FEA) on the spring model so that stress and damage distribution can be observed. In this paper, we describe its basic structure, stress characteristics, engineering finite element modeling for analyzing & high stress zones. The equivalent von-misses stresses are plotted.
INTRODUCTION
Development of a leaf spring is a long process which requires number of tests to validate the design and manufacturing variables. We have used CAE to shorten this development thereby reducing the tests. A systematic procedure is obtained where CAE and tests are used together. CAE tools are widely used in the automotive industries. In fact, their use has enabled the automakers to reduce product development cost and time while improving the safety, comfort, and durability of the vehicles they produce. In this paper work is carried out on the front end leaf spring of a mini-loader truck. The objective of this work is to carry out computer aided design and analysis of a conventional leaf spring. The material of the leaf spring is 55Si2Mn90. The CAD modeling and finite element analysis of the leaf spring is done in CATIA V5R20.
MATERIAL
The basic requirements of a leaf spring steel is that the selected grade of steel must have sufficient harden ability for the size involved to ensure a full martenstic structure throughout the entire leaf section. In general terms higher alloy content is mandatory to ensure adequate harden ability when the thick leaf sections are used. The material used for the experimental work is 55Si2Mn90. The other designation of this material is shown in Table-1 and its chemical compositions are shown below in Table -2.
CONCLUSION
This work involves design and analysis of a conventional leaf spring under static loading conditions. The 3D model is prepared in CATIA and then CAE analysis is also performed in the same software. The results obtained from CATIA using Simulated Annealing Algorithm, shows that the stress is minimized in the 90th iteration. So modification in parabolic leaf spring of mini loader truck can be done as camber and eye distance equivalent to 90.395007 mm and 1024.246478 mm to reduce the maximum stress.