热冲击下自增强反应器残余应力松弛研究

Study on Residual Stress Relaxation of Autofrettaged Reactor under Thermal Shock

基于Von Mise屈服准则,通过ABAQUS软件研究了热冲击对自增强超高压聚乙烯反应器残余应力的影响,得到了热冲击后自增强残余应力的分布情况,分析了热冲击下自增强反应器残余应力松弛的规律及原因。结果表明,在热冲击作用下主要在靠近反应器内壁2mm区域内残余应力发生了松弛,内壁的应力松弛率最大;热冲击过程热应力与自增强残余应力的叠加使近内壁区域产生了压缩切向塑性变形,导致反应器残余应力重新分布,当残余应力衰减到一定值时,热应力与残余应力的叠加值不足以使反应器继续发生切向塑性变形,此时残余应力不会继续衰减。

Based on the Von Mise yield criterion,the finite element software ABAQUS was used to studied the effect of thermal shock process on autofrettaged residual stress in the ultra-high pressure polyethylene reactor,the distribution of autofrettaged residual stress after thermal shock was obtained,and the law and reason of residual stress relaxation in autofrettaged reactor under thermal shock were analyzed.The results showed that the relaxation of the residual stress mainly occurred within 2 mm of the inner wall,and the relaxation rate of the inner wall was the highest;The superposition of the thermal stress and the autofrettaged residual stress caused the compressive tangential plastic deformation near the inner wall area,resulted in the redistribution of the residual stress of the reactor.When the residual stress relaxed to a certain value,the superposition was not enough to continue the tangential plastic deformation of the reactor,then the residual stress would not continue to relax.