颗粒增强复合材料中微观热应力和残余应力分析

运用空间配位体密堆模型和球对称分析单元，分析计算了颗粒增强复合材料经历温度变化后产生的微观热应力和残余应力。分析结果表明，温度升高时界面产生径向张应力，降温时产生压应力。存在一个基体开始发生塑性变形的临界温差ｔ＿ｐ，其值随增强体体积分数Ｖ＿ｐ增加而降低。除组元间热膨胀系数差和弹性常数外，基体材料本构关系和屈服强度对热应力和残余应力均有很大影响。随Ｖ＿ｐ增加，微观应力和水静宏观应力幅值上升。但粒子周围塑性区尺寸近似与Ｖ＿ｐ无关。给出了不同变温条件下残余应力的确定方法。

The Analyses on Thermal and Residual Microstresaesin Particulate Reinforced Composites

The thermal and residual microstresses in particulate reinforced composites have been elasto-plas-tically analysed,according to a densely stacked spatial ligands model and spherical symmetry analyticalelement. It is shown that. a constant hydrostatic stress p_0 in particles is induced and proportional to theteml)erature difference , difference of coefficients of thermal expansion (DCTE) and volume fractionof particles V_p and independant of particle size, the radial interfacial stress of matrix/particle is thesame as p_0 In matrix the radial stress with the sign of p_0 and tangential and circumferencial stress withthe opposite sign of p_0 are functions of radius.There exists a critical ternperature difference t_p over thatthe matrix near the interface begins to yield and its valuc decreases with the increase V_p Besides thedifference in coefficients of thermal expansion and elastic constants of constituents,there are signiffi-cant effects of constitutive relations and yield strength of the matrix on the stresses. The microstressesand macro hydrostatic stress both are increased with the increase in V_p while the yielded scale is approx-imately not affected by it.It was given out the method for determinations of residual stresses in twothermal fluctuations.