热-机载荷作用下随动强化管道安定性分析的改进数值方法

A MODIFIED SHAKEDOWN ANALYSIS FOR KINEMATIC HARDENING PIPING UNDER THERMAL-MECHANICAL LOAD

安定性分析是一种有效的预测压力管道在热-机载荷作用下的棘轮与交变塑性失效的方法。为了克服现有安定性分析方法无法同时考虑材料的随动强化行为以及温度对材料性能的影响的缺点,提出一种基于降维迭代法的数值算法。该算法将同时考虑随动强化和依赖于温度的屈服函数的安定性分析问题转化为具有固定屈服面的理想弹塑性安定性分析问题,降低了求解的复杂性。算例表明,方法可以提高热-机载荷作用下压力管道棘轮与交变塑性失效预测的准确性,具有一定工程应用价值。

Shakedown analysis is a powerful tool for the ratchet&alternating plasticity prediction of the pressure piping under thermal-mechanical loads.In order to achieve the shakedown analysis containing the synergetic influence of the kinematic hardening and the temperature-dependent properties of the material,a numerical method was developed.The presenting method is an extension of the two-surface model for shakedown analysis and is based on the basis reduction method.The idea is to transfer the nonlinear programming resulting from the shakedown analysis with kinematic hardening and temperature-dependent nature into an elastic perfectly plastic one which can be solved with less effort.Numerical examples indicated that the proposed method is accurate.This method has the potential to improve the accuracy of failure prediction for the piping suffering thermal-mechanical loads and therefore is of engineering values.