A Guideline for Fatigue Testing of Components

Abstract

Material properties, loading, geometry and manufacturing processes are considered as the major elements in fatigue design problems. The effect of geometry has always been one of the challenging issues for designers to face with. The methodologies to transfer material properties obtained from specimen fatigue tests to fatigue behavior of real components, where neither a nominal stress nor a notch factor could be defined, have not been completely accurate or reliable. Therefore, direct component testing, though time consuming and expensive, is often a necessity in fatigue design. Contrary to specimen testing, which numerous standards have been developed for, component testing is more a matter of designer’s practice. Various parameters such as simulation of the actual service condition, collecting useful data, and correspondence of the test results to analytical predictions determine the correctness and applicability of the conducted test. Based on previous studies regarding fatigue testing of components [1–9], this article intends to provide a step-by-step guideline to conduct fatigue testing, with a focus on automotive parts. Essential pretest, during-the-test, and post-test details are discussed. The guideline is implemented on sample steering knuckles and connecting rods as example parts, and the challenges and shortcomings for each test are investigated.