高温下编织复合材料热相关参数识别方法研究

THERMAL-RELATED PARAMETER IDENTIFICATION OF BRAIDED COMPOSITES AT HIGH TEMPERATURE

为了获取高温下编织复合材料的准确弹性参数与热膨胀系数,提出一种基于均匀化理论的热相关参数识别方法.首先,在编织复合材料单胞有限元模型基础上,基于均匀化理论和热弹性理论,施加周期性位移边界条件和温度边界条件,预测编织复合材料的热弹性相关参数.然后,考虑到等效过程中编织复合材料应力分布不均匀等因素引起的误差,将复合材料精细模型的热模态数据作为补充信息,识别编织复合材料热相关参数,对预测的材料参数进行校准.本文在二维编织结构单胞模型基础上,开展等效预测和识别方法研究,验证所提出方法的有效性和准确性.对比等效和识别后热模态的误差,结果表明:本文提出的基于等效预测的参数识别方法,能够准确识别高温下编织复合材料宏观热相关参数.

To obtain accurate elastic parameters and coecient of thermal expansion （CTE） of braided composites at high temperature, An approach for identifying thermal-related parameters based on homogenization theory is proposed. Firstly, on the basis of the finite element model of unit cell, the thermo-elastic parameters of the braided composites are predicted, basing on the theory of homogenization and thermos elasticity, and by applying the periodic displacement and temperature boundary conditions. Secondly, considering the errors in the equivalent process causing by the uneven distributed stress, the thermal modal frequencies of the refined model are taken as the supplementary information to further identify the thermo-elastic parameters, as a calibration of the predicted parameters. Based on the finite element unit cell model of two-dimensional braided structure, this paper carries out equivalent prediction and identification, to verify the validity and accuracy of the proposed method. after comparing the error of the thermal mode of equival model and identification model, it is shown that the proposed method based on equivalent prediction and parameter identification can accurately identify the macro-thermo-elasticity related parameters of braided composites at high temperature.