PSI - Issue 38

Ronald Schrank et al. / Procedia Structural Integrity 38 (2022) 30–39 Ronald Schrank / Structural Integrity Procedia 00 (2021) 000 – 000

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Keywords: automotive; fatigue, text, optimizaion

1. Motivation Serial approval of automotive chassis parts (for instance wheel suspension components like knuckles, control arms, subframes etc.) is based on complex and expensive full/half- axle fatigue tests, further called “full test”. However, component-based simplified fatigue tests – further called “simplified test” – are often desired within earlier development phases, for reasons of quality assurance due serial production or others. Simplified tests should be time- and cost-saving, however, they have to reproduce the fatigue behavior of the full test in the best way. The fatigue behavior can be described in terms of fatigue damage, see Radaj et al (2007) for basic fatigue theory.

Table 1. Full fatigue test vs. simplifies fatigue test Full test

Simplified test

Characterization

full/half axle fatigue test complete wheel suspension assembly large deflections due to vertical stroke complex loading (variable amplitude loads, time-history loads)

single part fatigue test little number of components (e. g. bushings) small deflections (the part's elasticity only) simplified loading (constant amplitude loads, periodic/harmonic)

Pro´s

best reproduction of reality best accuracy

time saving cost saving

Con´s Application

most expensive in time and costs used for final validation and serial approval

limited accuracy used for intermediate validation / production monitoring

Fig. 1. (left) full fatigue test; (right) simplified fatigue test.