内压弯管在多轴循环外力下的棘轮应变数值分析

FEM analysis of ratcheting predicion of pressure tube under multiaxial cyclic pressures

弯管在流体压力、热载荷及振动载荷作用下,处于复杂应力状态,其棘轮应变分析很难通过解析计算的方法实现。本文利用有限元法对压力弯管进行多轴棘轮应变分析,采用基于Chaboche模型基础上的非线性随动强化定律,更新弹塑性有限元计算所采用的本构关系,通过一典型的弯管实例进行了数值分析,预测其棘轮应变,考察其塑性应变行为,为结构设计提供依据。

Tubes usually works in combined external loads such as thermal loads, fluid pressure and vibrating loads. The stress state is very complicated and it is very difficult to obtain its ratcheting strain analytically. In the paper, FEM is used to analyze the ratchetting strains of pressure tube. The Chaboche nonlinear kinematic hardening rule based on constitutive model is adopted to account for the phenomenon of strain accumulation. A typical tube under multiaxial pressures is chosen for case study. The results of ratcheting strain distributions can be served well to discover the plastic deformation history and supply a reference for further structure design.