基础随机激励下纤维增强复合薄板振动疲劳寿命预报

针对传统有限元建模黑箱操作多、计算成本大、不具有自主知识产权等问题，基于经典层合板理论，随机振动理论和Miner线性积累损伤准则，建立了基础随机激励下纤维增强复合薄板振动疲劳寿命预测的解析模型。基于应力模态法，推导了纤维增强复合薄板的应力频响函数，在考虑随机激励的基础上，得到了结构的随机振动等效应力功率谱密度函数。通过Dirlik、Bendat和Benasciutti-Tovo三种频域模型对应的概率密度函数，成功求解了相应的振动疲劳寿命。另外，采用ANSYS与nCode软件对模型及其预测结果的正确性进行了验证，研究发现该模型寿命计算结果相对于商业软件计算结果的偏差不超过14.8%，但计算效率提高了17%～33%。因此，该模型可为预测随机激励下各向异性复合薄板的振动疲劳问题，提供一种思路和工具。

Vibration fatigue life prediction of fiber reinforced composite thin plate under basic random excitation

In order to solve the problems of traditional finite element modeling such as black box operation, high computational cost and lack of independent intellectual property rights, an analytical model for vibration fatigue life prediction of fiber reinforced composite thin plate under basic random excitation based on classical laminated plate theory, random vibration theory and Miner's linear accumulation damage criterion was established. Based on the stress modal method, the stress frequency response function of the fiber reinforced composite plate was deduced, and the random vibration equivalent stress power spectral density function of the structure was obtained considering the random excitation. Based on the probability density function corresponding to the Dirlik, Bendat and Benasciutti-Tovo frequency domain models, the corresponding vibration fatigue life was solved successfully. In addition, the correctness of the model and prediction results were verified by using ANSYS and nCode software. It was found that the deviations of life calculation results obtained by this model and the above commercial software were less than 14.8%. However, the calculation efficiency was improved by about 17% to 33%. Therefore, the model can provide an idea and a tool for predicting the vibration fatigue of anisotropic composite sheet under random excitation.