残余应力对复合材料弹-塑性变形的影响

INFLUENCE OF RESIDUAL STRESS ON ELASTIC-PLASTIC DEFORMATION OF COMPOSITE MATERIALS

从细观力学的角度给出了分析残余应力对一般复合材料塑性性能影响的一种解析方法 ,该方法基于应力二阶矩的割线模量法及 Ponte Castaneda和 Willis给出的弹性细观模型。有残余应力时 ,所提的细观解析模型能够同时考虑纤维形状 ,体积百分比 ,纤维取向及纤维的分布对复合材料变形的影响。计算结果表明 ,残余应力的存在会引起复合材料拉压变形的不对称 ,材料宏观的拉压硬化曲线又与复合材料的细观结构参数密切相关。对单向复合材料 ,本文作者对其等效割线热膨胀系数 ,拉压应力 -应变曲线的有限元分析结果与给出的细观解析模型定量吻合。

A micro mechanical method is proposed to account for the influence of thermal residual stress on elastic plastic deformation of composites. The method is based on the secant moduli method with second order stress moment and the elastic micro mechanical method proposed by Ponte Castaneda and Willis. This model can account for the influence of volume fraction, shape, orientation, and distribution of inclusions on macroscopic properties of composites with or without thermal stress. Finite element calculations are also carried out for unidirectional composites and compared with the proposed model.