Fatigue Simulations for Automotive Components undergoing Vibration Loadings: effect of nonlinear behavior

Abstract

Modern automotive customers are demanding for faster and faster product development, from initial response for quotation (RFQ) to serial production. Finite Element Analysis (FEA) is a powerful tool applied to design validation (DV). In Valeo, FEA and Reliability teams have been working together to establish a robust methodology for the simulation of vibration fatigue at the design validation phase.This paper goes in the framework of using modern simulation tools to routinely validate the goodness of a design.Previous investigations had shown that “simple” DV simulation based on the material's ultimate tensile strength (UTS) tend to be conservative and basically targeting an infinite fatigue life endurance.The present study aims at simulating the design validation of relatively complex systems (multi-materials components, prototype parts, representative system integration) in the high cyclic fatigue domain: the goal is to rely on FEA as early as possible even before official nomination (e.g. RFQ phase).This paper will present an example of a car engine cooling module (ECM) undergoing vibration loadings.The simulated fatigue will be obtained by different calculation methods, such as modal linear and non-linear approaches and time domain methods. A case study will illustrate a practical application of the presented methods. The results of the different methodologies, expressed as predicted time to failure, will be compared and analyzed.The objective of the study is to compare the results obtained from the different approaches when applied to durability design validation of an industrial cooling system undergoing vibration fatigue loadings.