High Frequency Vibro-Acoustic Fatigue Analysis with a Radiosity Based Theory

The high-frequency structural-acoustic coupling problems have received much attention in recent years. For instance, satellites and space equipment are exposed to diffuse acoustic fields during the launch process. The pressure has abundant high-frequency components, and the structural fatigue problem cannot be ignored. The traditional deterministic methods, such as Finite Element Method (FEM) and Boundary Element Method (BEM), are not suitable for these high-frequency problems. This article takes the one-dimensional beam and two-dimensional plate components , commonly used in the actual structure, as the research object. With a radiosity based theory, the conversion relationships between the vibration energy density and the power flow intensity and structural dynamic stress are deduced. By comparing the simulation results with the theoretical solution, the validities of the conversion models are verified. And by comparing with the traditional Energy Finite Element Method (EFEM) and the Statistical Energy Analysis (SEA) the superiorities of the conversion models are verified in high frequency stress estimation. The stress estimation models proposed in this paper are used to estimate the structural high-frequency vibration stress power spectrum, and finally combining the zero-order moment stress spectrum method to perform frequency domain fatigue prediction of the structure.