Synthesis and validation of accelerated vibration durability tests

This study illustrates a methodology used in our company (car components manufacturer) which enables to generate, starting from any given customer vibration specification, a fatigue damage equivalent Power Spectrum Density (PSD) signal. This PSD can be used to evaluate the mechanical durability of engine cooling or engine-mounted components. The methodology permits to accelerate durability bench tests, to compare the severity of different vibration specifications and to perform structural simulation. One practical example will illustrate the experimental validation of the procedure, based on strain-damage measurements. The main limitations of the methodology are related to the nature of the specified signal. In the case of specifications composed of purely random signals, the method is always applicable.