Application of CAE Hood-Slam Simulation On Evaluation of FEM Functional Life

Hood opening/closing is a necessary function in a vehicle, but the closing often results in an impact known as hood slam. The damage to the components of the FEM (Front End Module), induced by the hood slam, accumulates over the vehicle lifetime and may lead to failure. In a traditional design process, an impact test is conducted on prototype FEM to evaluate its integrity. It is, however, very costly and time-consuming to achieve a statistical based confidence. Presented in this paper is a methodology of CAE hood-slam simulation that intends to replace the test and drive FEM design.

This CAE method includes two aspects: impact simulation and fatigue life evaluation. An impact loading is applied by converting potential energy to kinetic energy, mimicking the hood dropping from a specified height on the hood latch. The impact loading causes the local deformation and stress concentration, which may become potential failure spots. The stress time history from the impact simulation is used to calculate the functional life of the FEM.

This paper demonstrates the benefit of CAE technology to the FEM product development.