Analysis of random vibration fatigue of aluminum alloy beam with a hole based on frequency domain method

Abstract

Based on the frequency-domain method, the influence factors of vibration fatigue life of aluminum alloy beam with a hole was analyzed. Firstly, the finite element model of aluminum alloy beam with a hole was established, and modal analysis was performed to obtain the natural frequency and mode shape of each order. And then, harmonic response analysis was employed to determine the direction and natural frequency of vibration that has the greatest impact on the structure. After that, fatigue life of the structure was studied. The in-fluence of model method, power spectral density, natural frequency order, frequency band, bandwidth and other factors on fatigue life was analyzed by changing excitation load conditions. Through the simulation, the results indicate that: Fatigue life calculated by Steinberg and Lalanne method is more conservative than that calculated by Dirlik method under the same excitation load. The accelerated fatigue life test can be performed by changing the power spectral density value. The power spectral density value of the excitation load at the first natural frequency plays a major role in the fatigue life. The quantitative relationship between central band fatigue and full frequency fatigue is established.