扩散声场作用下C/SiC复合材料薄壁结构的全频段响应分析

为了获取复合材料薄壁结构在扩散声场作用下的全频段应力响应，在70 m3混响室内进行自由状态下的C/SiC复合材料薄壁结构的噪声试验（总声压级140 dB），测试混响室内扩散声场以及结构的加速度响应。另，建立扩散声场与正交各向异性复合材料薄壁结构相互作用的有限元–统计能量（FE-SEA）混合模型，计算得到结构的加速度响应分布，计算结果与试验测试结果一致。同时，基于模态应力恢复方法获得结构的应力场分布，结果显示扩散声场作用下的复合材料薄壁结构的应力场分布与加速度场分布规律不同。通过分析复合材料薄壁结构的弯曲波长与声波波长之间的关系，揭示噪声载荷与结构的波长耦合效应。该FE-SEA混合模型计算的应力场可进一步应用于声疲劳分析。

The full spectrum stress field in C/SiC composite thin plate structure under a diffusive acoustic field

The experiments and the simulations are performed to analyze the full spectrum acoustic response of a composite thin plate structure under a diffusive sound field (SPL=140 dB). In a typical reverberation chamber, the diffusive sound field and the structural acceleration responses are measured for the C/SiC composite structure. A hybrid FE-SEA model is established for simulating the interactions of the orthotropic composite thin plate structure with the acoustic load, and the simulation results are in agreement with the experimental tests. Meanwhile, the stress field inside the composite structure is obtained by the modal stress recovery method. It is shown that the distribution of the stress field is different from that of the acceleration field for the composite structure under the diffusive sound field. The relation between the structural bending wavelength and the acoustic wavelength is analyzed to reveal the coupling mechanism between the acoustic load and the composite structure. The stress field obtained by the hybrid FE-SEA model can be further applied to the acoustic fatigue analysis.