Study of improved fatigue damage calculation of spacecraft equipment under wideband random vibration excitation by applying Rice distribution

Abstract

This paper presents an improved calculation method of fatigue damage in spacecraft equipment under wideband random vibration. The method is based on principle of linear fatigue damage theory (Miner’s rule) to calculate accumulated fatigue damage, where the calculation of stress cycles is improved by more general Rice distribution instead of conventional Rayleigh distribution, which has been commonly used for decades. Examples of numerical simulation and test data of spacecraft equipment are used to demonstrate the accuracy of these two different statistical distributions and show that the generated stress of the equipment subject to wideband random vibration excitation would be filtered into a narrowband random stress response due to resonance of equipment. However, the statistical distribution of peak value of the narrowband random stress response can vary depending on the spectrum of excitation and resonance frequency and differs from the conventional Rayleigh distribution assumption. This paper, through the numerical and test examples, demonstrates that the improved method is a more feasible method which can create more accurate and less conservative accumulated fatigue damage than the conventional Rayleigh distribution.

Keywords

• fatigue damage
• rice distribution
• rayleigh distribution
• miner’s rule
• acoustic test
• random vibration test
• narrowband random
• wideband random
• irregurality