钛合金材料IMI834高温蠕变和蠕变断裂的连续损伤力学分析

CONTINUUM DAMAGE MECHANICS ANALYSIS OF HIGH TEMPERATURE CREEP AND CREEP FRACTURE FOR TITANIUM ALLOY IMI834

对工作在650℃下的航空发动机用高温钛合金材料IMI834的高温蠕变和蠕变断裂行为进行连续损伤力学分析研究,预测结构件的蠕变断裂寿命,得到的结果和试验数据相吻合。用有限元软件ANSYS分析半圆形缺口圆棒试样的应力应变状态,得到应力三轴因子,进而考虑多轴应力状态对材料蠕变断裂寿命的影响,表明多轴应力显著地降低结构的蠕变断裂寿命。分析结果显示,文中所用的蠕变损伤模型能够合理地描述材料蠕变损伤的累积发展过程,并正确地预测结构件的蠕变断裂寿命。

A nonlinear continuum damage model was employed to study the creep and creep rupture behaviour of an aeroengine material, a high temperature titanium alloy （IMI834）, at 650℃. The results predicted by the model utilized were found to be in good agreement with the experimental results. The distribution of file stress triaxiality factor in an axisymmetric semicircular notched specimen was achieved by the stress analysis using the finite element method （FEM）, then the influence of the multi-axial stress state was considered in the creep damage analysis. It was found that the multi-axial stress state remarkably reduces the creep fracture life of the structures. The results prove that the multi-axial creep damage model can describe the cumulation and development of damage and predict the creep rupture life more accurately.