基于损伤力学的周向拉杆转子整体疲劳损伤研究

Research on the whole fatigue damage of circumferential rod fastening rotor based on damage mechanics

周向拉杆转子作为燃气轮机等重大装备的核心部件,疲劳损伤是导致其失效和性能退化的主要原因之一。目前对疲劳损伤的研究均是针对单个元件,而仅从单个元件的损伤依然无法预测整个周向拉杆转子的损伤。以某型燃气轮机周向拉杆转子为研究对象,考虑周向拉杆转子燃烧室损伤和透平端拉杆损伤对周向拉杆转子整体损伤的影响,建立了周向拉杆转子整体疲劳损伤模型。通过对周向拉杆转子轮盘间接触效应的等效,建立了考虑虚拟材料层的周向拉杆转子动力学模型,得到了周向拉杆转子各组成部分刚度及其整体等效刚度;运用损伤力学及有限元分析,提出了周向拉杆转子整体疲劳损伤建模方法,得出周向拉杆转子的整体疲劳损伤及元件损伤与致裂寿命的关系。结果表明:所建立的损伤模型将周向拉杆转子整体损伤和致裂寿命视作一个复杂、非线性的过程,考虑了多元件损伤的影响,可清楚反映多元件损伤与整体损伤的非线性关系。研究结论为周向拉杆转子结构设计和寿命预测等提供了理论参考。

Circumferential rod fastening rotor is the core part of gas turbine,and fatigue damage is one of the main reason that cause the circumferential rod fastening rotor failure and performance degradation.The research object of fatigue damage is single component at present,so it is not accomplished to predict the whole fatigue damage with fatigue damage of single component.Taking the circumferential rod fastening rotor of a certain gas turbine as the study object,the total fatigue damage model of circumferential rod fastening rotor which considering fatigue damage of the rods of turbine and combustion chamber was built with the equivalent of contact effect between rotor and rod.And a dynamics model of circumferential rod fastening rotor considering interface contact effect was built.Then equivalent stiffness of the whole and parts was calculated with analytical model.Furthermore,fatigue damage modeling method of the whole circumferential rod fastening rotor was proposed with damage mechanics and finite element analysis to get the relation between the total damage and rupture life.The results showed that the relation between the total damage and rupture life was a complicated,non-linear course and non-linear relation between the whole damage and element damage was clearly reflected when multielement damage considered.The results of this dissertation can be a support for structural design and life prediction of rod fastening rotor.