C/SiC复合材料结构件热模态模型建模和修正方法

Modeling and modification methods of thermal modal model of C/SiC composite structure

C/SiC材料是一种热的不良导体,在防热隔热领域具有重要的潜在应用前景。本文开展了C/SiC结构件的有限元模型修正方法研究。在热弹性理论的基础上推导了各向异性材料的应力‑应变关系,建立了C/SiC复合材料层板在高热流密度条件下的系统泛函。建立了考虑温度效应的C/SiC复合材料结构的动力学有限元模型。提出了基于多层级思想的C/SiC复合材料结构模型修正方法。以模态频率差值最小为修正目标,复合材料力学、热学参数为修正变量,开展模型修正。模型修正结果表明,本文提出的方法具有良好的修正效果,能够准确修正结构热环境下的复合材料参数及边界条件。

C/SiC material is a kind of poor thermal conductor and has important potential applications in the field of thermal insulation.The finite element model modification method of C/SiC structural parts is studied in this paper.Based on the elastic theory in thermal environment,the stress-strain relationship of anisotropic materials is deduced,and the system functional of C/SiC composite laminates under high heat flux conditions is given.The Hamiltonian formula of composite laminates is derived,and the kinetic energy and potential energy of composite laminates are calculated.The C/SiC typical component-level structure finite element model for calculating thermal environment of structural dynamics is established.The dynamic finite element model of the C/SiC com‑posite structure considering temperature effect is established.A method of modifying the C/SiC composite structure model based on the multi-level idea is proposed.With the minimization of the modal frequency difference as the correction objective,and the mechanical and thermal parameters of the composite as the correction variables,the hierarchical model is modified.The model modification results show that the proposed method has good correction effect and can accurately correct the composite material parameters and boundary conditions in the thermal environment of the structure.