复合材料中增强粒子与基体中微观应力和残余应力分析

按球对称模型对粒子增强复合材料中热膨胀差(DCTE)热应力和残余应力进行了弹-塑性分析。结果表明,热应力或残余应力具有短程分布特点;粒子内部为常水静应力,界面和基体中径向应力与粒子内部同号,切向和周向应力与径向应力符号相反。存在一个基体发生初始屈服的临界温差t_P,屈服范围随温差|t|而扩大。单程变温产生的残余应力与热应力完全相同;经过一个热循环后,若温差小于t_P则残余应力为零;若大于t_P,则在粒于和基体中产生残余应力。讨论了粒子形状和尺寸对残余应力和基体塑性变形对复合材料性能的影响。

ANALYSES OF THERMAL AND RESIDUAL MICROSTRESSES IN PARTICLE AND MATRIX OF COMPOSITES

Elastic/plastic analyses are conducted on thermal and residual microstresses inparticulate reinforced composites,according to a spherical symmetric model.It is shown thatthe thermal or residual stresses have a characteristic of short-range distribution;in a particlethere is a constant hydrostatic pressure as the temperature drops,and there is a tension asthe temperature rises. The radial stresses at the interface and in the matrix have the samesign as that in the particle,though the tangential and circumferential stresses'sign isopposite to that in the particle,There exists a critical temperature difference t_p over whichthe matrix near the particle starts to yield,and the yielded scale will expand as thetemperature difference increases. The residual stress field is the same as the thermal one asthe temperature changes. After a thermal cycle the residual stress field is zero when |t|