超高压管道的疲劳损伤研究

通过将超高压管道在疲劳载荷作用下的损伤归结为无初始应力集中的大范围疲劳损伤问题,根据应变疲劳的破坏机制,以应变幅为损伤变量,建立了损伤演化方程,利用虚功原理得到了超高压管道疲劳裂纹萌生寿命计算模型,探讨了交变内压作用下模型参数的计算问题.模型不仅考虑了材料的疲劳特性,同时考虑了管道结构和载荷作用情况,当退化为简单试件的疲劳寿命计算式时,能很好地拟合3种常用超高压容器用钢30CrN iMo8、ANSI4340H和G4335V的疲劳试验数据.

Fatigue damage study of the ultrahigh-pressure pipe line

Consider the damage of the pipe line under fatigue load as fatigue problem under large scale damage, the fatigue damage evolution equation was derived based on the strain fatigue damage mechanism, where strain magnitude was the damage variable. The fatigue crack initiation life equation of ultrahigh-pressure pipe line was obtained by the principle of virtual work and the calculation of parameters of the model under alternating internal pressure was discussed. Not only the fatigue characteristic of material but also the structure and the load of pipe line were considered in the equation. When the equation is simplified for the simple specimen, it can fit for the raw of the test data of the three steels 30CrNiMo8, ANSI4340H and G4335V often used in ultrahigh-pressure vessel.