THERMAL-RELATED PARAMETER IDENTIFICATION OF BRAIDED COMPOSITES AT HIGH TEMPERATURE

To obtain accurate elastic parameters and coefficient 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.