Thermal performance prediction and verification of 2D triaxial braided composites based on coupling method

In order to improve the shortcomings of the finite element unit-cell establish method based on traditional FEM, which has difficulty in meshing and calculation, a superimposed method was proposed. Based on the superimposed method, the finite element unit-cell model of two-dimensional triaxial braided composites was established. Based on the coupling method, the coordination relationship between degree of freedom of element grid of displacement field and temperature field from reinforcement and matrix were given, and the match method of superimposed region thermal properties and the periodic boundary conditions of the unit-cell model temperature field were determined. The equivalent thermal conductivity coefficient and the equivalent thermal expansion coefficient of the unit-cell model were obtained by applying the periodic boundary conditions. Based on this method, the thermal properties of two-dimensional triaxial braided composites were predicted and analysed. The results show that different braiding angles and fiber volume faction have certain effects on the thermal conductivity coefficient and thermal expansion coefficient in different directions.