载荷路径对内压弯管棘轮效应的影响

摘要

Ratcheting deformation was studied on elbow pipe made of Z2CND18.12N by FEM software. Chen -Jiao -Kim (CJK)kinematic hardening model was incorporated in ANSYS to ensure the accuracy. The elbow pipe was subjected to internal pressure and reversed in -plane bending.Many different loading paths were considered.Ratcheting deformations under different paths were studied.Ratcheting deforma-tions of same path in different directions were also studied.The result showed that highest ratcheting strain mainly occurs in the circumferential direction at the intrados,but the values were different.The influence of loading paths on ratcheting deformation is mainly due to different internal pressure conditions when ap-plying the bending load.The process of applying bending load first and then increasing internal pressure can greatly decrease ratcheting deformation of elbow pipes.Comparing ratcheting boundaries of original path and optimized path,it can be concluded that optimized path increases ratcheting boundary of elbow pipe.%采用有限元软件对 Z2CND18．12N 不锈钢弯管的棘轮变形现象进行研究，将 Chen －Jiao －Kim （CJK）随动强化模型嵌入 ASNYS 软件来保证模拟过程更加准确。弯管受到内压和交变面内弯曲载荷的作用，采用了多种的加载路径，研究了不同的加载路径条件下的棘轮变形，同时也研究了同一路径、不同方向对棘轮变形的影响。研究结果表明，在不同加载路径条件下，棘轮应变最大值都出现在了内缘线位置的环向，但棘轮应变值有一定的差别。不同路径对弯管棘轮效应的影响主要由于弯曲载荷施加过程中内压的不同，先施加弯曲载荷再提高内压的过程会极大地降低弯管棘轮效应。通过对路径优化前后弯管棘轮边界对比可以看出，路径的优化提高了弯管的棘轮边界。