An accurate and efficient computational method for structural dynamic stresses under random loading

Abstract

One of challenging issues in structural random analysis is to accurately predict the dynamic stresses. It is even important for fatigue life prediction and strength-safe design. This paper proposes an accurate and efficient computational method to obtain the dynamic stresses of structures under random loading. Firstly, the random loading given by PSD is transferred into harmonic functions. Meanwhile, structural modal stress analysis is conducted. Based on the modal stress superposition and the equivalent treatment for higher modal responses, the dynamic stresses are determined. It consists of two parts: one is from the modal stress superposition, and the other is from the equivalent analysis including the contributions of the ignored higher modes. This new method is verified by the experiment conducted in our laboratory, showing that the dynamic stresses predicted by the new method agree well with the experimental results, and it is of high computational efficiency. The proposed method can be easily applied to dynamic stresses prediction for engineering structures under random loading.