基于均匀化理论的4D轴编C/C复合材料的细观力学性能预测

Forecast research on micromechanical properties of 4D in-plane C/C composites basedon homogenization theory

为实现4D轴编C/C复合材料细观力学性能的预测,首先针对4D轴编C/C复合材料的结构特点,建立了其代表性体积单元;然后利用均匀化理论和周期性边界条件为理论基础,编写了一般周期性边界条件子程序作为位移边界条件,分析讨论了代表性体积单元的变形特征、应变分布特征,获得了等效刚度矩阵;同时与编写的周期性边界条件子程序作为位移边界条件情况下的计算结果和已有实验结果分别进行了对比。研究结果表明,随着界面强度的增加,一般周期性边界条件预测的材料力学性能相比周期性边界条件预测情况下的误差小,更接近实验数值,从而验证了编写的一般周期性边界条件子程序的有效性和正确性,并进一步得出了代表性体积单元参数对材料力学性能的影响规律,得到了一些有一定指导意义的结果。

In order to get a prediction method about micromechanical properties of four directional(4 D) in-plane carbon/carbon composites,representative volume element is firstly given according structure of 4D in-plane carbon/carbon composites.The subprogram of the aperiodic boundary conditions is realized as a displacement boundary condition using the homogenization method and periodic boundary conditions as a theory basis.The deformation feature and strain distribution feature are discussed,and then the equivalent stiffness matrix is computed.The results have been compared with the results of subprogram of the periodic boundary conditions and experiments values.With the increase of interface strength,the mechanical properties of materials predicted by the aperiodic boundary conditions are with less error than those under the periodic boundary conditions,which is closer to the experimental values.The validity and applicability of the aperiodic boundary conditions has been verified.At the same time,the effect of material parameters on mechanical properties has been further obtained and some valuable result is acquired.