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With advancements in powertrain technologies & light weighting of vehicle structures, the average driving speeds of motorcycles are increasing. This makes it important to safeguard the vehicle structure from possible impact loads or crash events. The front suspension of a motorcycle typically consists of telescopic front fork which acts as a structural member as well. Thus modern vehicle front forks should be designed keeping in mind frontal impacts as well. Which means the structural stiffness of front fork needs to be optimally designed so that during impacts, the structure should deflect absorbing the bulk of the impact energy safeguarding the rest of the vehicle structure including chassis. At the same time the front fork should not break. The popular design improvement techniques like increasing section modulus, heat treatments to increase strength may or may not have positive effect on impact strength.

Automotive shock absorber shims are subjected to deformation while generating the pressure differential across the rebound and compression chambers. Considering the contact, large deflection, and material this shim stack deformation will be nonlinear throughout the working velocity of shock absorbers. The deformation of shim stack mainly depends on number and geometry of deflection disk, number and geometry of ports, and clamping disk geometry on which shims are rested. During the rebound and compression stroke of the shock absorber, the oil flows through the piston and base valve ports. High pressure oil developed during mid and high velocity of shock absorber results in deflection of shim stack in piston and base valve assembly. This deflection leads to oil leakage through the shim stack which results in change in damping force by the shock absorber.

In an automotive twin tube shock absorber, thin structures used in piston and base valve sub-assembly are called shims. These shims are used in proper combination to achieve particular damping force characteristics and these shims will be operating continuously throughout the life of shock absorber. Any failure of shims during lab/ vehicle testing will increase the development time and cost considerably. Hence, predicting the operating life of shim assembly is very important during shock absorber development stage. In order to predict the life of the shim assembly, simulation techniques can be applied with fair degree of accuracy. Currently, during structural simulation of shim assembly, it is assumed that fluid pressure is acting uniformly over the entire shim to find stress intensity. This approximation is taken into account to predict the fatigue life of shim assembly. This paper proposes additional technique to carry out close to real life shim simulation.