Experimental and Numerical Study of Fatigue Life in Aluminum 6061-T6 under Stochastic Loading

Abstract

Numerically determining fatigue under stochastic vibrations are typically performed use computational intensive transient response models. This research will delve into an alternate less computation intensive method of applying linear modal analysis combined with Power Spectral Density (PSD) excitation functions to develop resultant stress PSD Functions. Statistical methods can be applied to evaluate the stress range occurrences. This research will compare the methods possible for such fatigue estimations by experimentally testing 6061-T6 under stochastic excitation induced by a hydraulic shake table. The experimental evaluation will also delve into the methods of measuring damping for numerical model application. This will be proven to be critical for accurate calculations of the stress frequency response functions. Resonance of the structure is also included in this experimentation to ensure the damping value is critical in developing correct stress response functions. The findings from the various approaches will provide guidance for application of spectral methods of fatigue life estimation for aluminum under high cycle low stress amplitudes.