考虑应力松弛的单晶涡轮叶片蠕变疲劳寿命预测

发布时间：2018-05-24 02:03

本文选题：单晶涡轮叶片 + 应力松弛　；参考：《航空动力学报》2016年03期

【摘要】：建立了民用航空发动机单晶涡轮叶片考虑应力松弛的蠕变疲劳寿命预测方法,该方法在热弹性蠕变有限元计算基础上,综合单轴等应变松弛模型及多轴应力修正因子预测全寿命周期内的应力松弛历程,应力下限取为一次应力.利用综合时间硬化隐式蠕变方程描述蠕变变形,结合损伤雨流计数法及Morrow方程计算疲劳损伤,基于Robinson法则的分段损伤线性累积方法计算全寿命周期内的蠕变损伤,总损伤达到临界损伤时获得蠕变疲劳寿命.通过对公开的单晶材料蠕变疲劳数据的分析,临界损伤定为0.5.结果显示,考虑应力松弛的蠕变疲劳寿命是不考虑应力松弛的45.6倍.为保证可靠性而兼顾经济性,叶片寿命预测时,可先有限元循环加载n个循环,再利用所提出的方法预测2n个循环内的应力松弛历程.
[Abstract]:A creep fatigue life prediction method considering stress relaxation for single crystal turbine blade of civil aviation engine is established. The method is based on the finite element calculation of thermoelastic creep. The uniaxial iso-strain relaxation model and the multiaxial stress correction factor are used to predict the stress relaxation history in the whole life cycle. The lower limit of the stress is taken as the primary stress. The comprehensive time hardening implicit creep equation is used to describe the creep deformation, the damage rain flow counting method and the Morrow equation are used to calculate the fatigue damage, and the piecewise damage linear accumulation method based on the Robinson rule is used to calculate the creep damage in the whole life cycle. The creep fatigue life is obtained when the total damage reaches the critical damage. Through the analysis of the published creep fatigue data of single crystal material, the critical damage is 0.5. The results show that the creep fatigue life with stress relaxation is 45.6 times longer than that without stress relaxation. In order to ensure reliability and economy, the finite element method can be used to predict the stress relaxation history of 2n cycles before loading n cycles by finite element method.
【作者单位】：中国航空工业集团公司中航商用航空发动机有限责任公司上海商用飞机发动机工程技术研究中心;西北工业大学力学与土木建筑学院;
【基金】：上海市“引进技术消化与吸收”专项资金(12XI-04) 中国航空研究院上海分院指南项目(AR024)
【分类号】：V232.4

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