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The Radial fatigue test is intended to find the structural performance of a wheel for normal highway use on passenger cars, light trucks and multipurpose vehicles. The wheel has to withstand repeated radial loading for a defined number of cycles in order to pass the test. The fatigue life of a wheel subjected to the repeated loading is calculated from the stress values obtained from static analysis. The accuracy of stress value depends on various parameters like tire modeling, simulation methods, load applications etc. This paper describes the tire finite element model representation and its validation, radial fatigue test simulation process and the physical testing correlation. Tire vertical stiffness plays a vital role in the radial test as the tire transfers the load from driven drum to the wheel. Tire vertical spring rate testing is done as per the SAE J2704 standard and the same condition has been simulated in CAE.

Airdam is an aerodynamic component in automobile and is designed to reduce the drag and increase fuel efficiency. It is also an important styling component. The front airdam below the bumper is to direct the air flow away from the front tires and towards the underbody, where the drag coefficient becomes less. The flexible airdam is made of Santoprene™ - thermoplastic vulcanizates (TPV), which belongs to thermoplastic elastomer (TPE) family. When a vehicle is parked over a parking block, the flexible airdam will be under strain subjected to bending load from the parking block. If the airdam is kept under constant strain for a certain period, a set will occur and the force will decay over a period of time. Due to the force decay, the stress will reduce and this behavior is called as stress relaxation.

The wheel impact test evaluates wheel structural performance for a typical lateral curb impact event occurring in passenger cars and light trucks. This test which is as per SAE J -175 standard has a striker dropped from a specified height on to a fixture mounted wheel-tire assembly. This impact test performance is critical to meeting overall structural performance for the wheel. There are many processes and methods available to simulate impact tests using FE analysis and in this study, certain existing methods are fine tuned to facilitate improved correlation with aforementioned lab test. Abaqus explicit is used in the simulation process and FE analysis-test correlation is achieved within 3% (strain gauge measurements). The improved method closely captures the behavior of the wheel during and after impact including capturing the variation of bolt pretension during the impact test. The wheel width before and after impact is another parameter used to compare analysis and test results.