温振复合载荷作用下多层壳结构随机振动响应有限元分析

FINITE ELEMENT ANALYSIS OF RANDOM VIBRATION RESPONSES FOR MULTILAYER SHELL STRUCTURE APPLIED WITH COMBINED TEMPERATURE AND VIBRATION ENVIRONMENT

介绍受复合载荷作用结构动力分析的背景和意义。从工程应用的角度,探讨温度与随机振动载荷作用下结构动态响应的有限元分析技术,包括对流边界条件下温度场的求解、热应力计算、预应力刚度矩阵的建立、响应功率谱分析等。然后以一种典型多层壳结构为研究对象,根据其在温振复合试验中的受试状态建立有限元模型。在此基础上,采用模态迭加方法和等效黏滞性小阻尼条件,计算复合载荷作用下的振动加速度响应,并与单一振动载荷作用结果进行对比,结果发现,由于环境温度的升高,结构的振动模态频率降低,而振动响应增大。分析结果可作为多层壳结构可靠性试验方法选取的参考依据。

The background and significance of dynamic analysis were introduced for the structure suffering from combined environment. Focusing on practical application, finite element simulation technology was discussed for engineering structures applied with combined temperature and vibration environment, including solution of temperature field with convectional boundary condition, thermal stress computation, forming of prestress stiffness matrix, analysis of response power spectrum et al. Then taking a typical multilayer shell structure as object, the finite element model was set up, according to its testing status during the combined temperature and vibration environment tests. Based on the mentioned model, using medal superposition method and assuming equivalent viscidity damping, responses about vibration acceleration have been calculated and compared with that of results obtained from the instance with vibration environment only. The results show that the modal frequencies reduce and yet the vibration responses increase due to the ambient temperature increment. Analytic results may serve as reference for selection of rehability test method to multilayer shell structure.