关键词: Mod.9Cr-1Mo钢;缺口件;非比例载荷;有限元分析;疲劳寿命预测

Abstract: A series of tests for low cycle fatigue are conducted for the notched specimen of Mod.9Cr-1Mo ferrite steel under multiaxial loading. The test results show that the initiation life is 60%-77% of the total life for all the strain paths, except circle path. On the whole, the scatter degree is smaller comparing with previous results from the literatures. ANSYS software is used for simulating and the Von Mises yield criterion, multilinear kinematic hardening rule and uniaxial cyclic stress-strain curve are employed to indicate the material elastic-plastic behavior. In the cylindrical coordinate, one end is fixed and another one is subjected to the axial displacement and circumference displacement to gain the strain control as those in the test. For all strain paths, the stress concentration is observed in the notched root and the maximum of the first principal strain and Von Mises strain occur in the notched root. Smith-Watson-Topper(SWT) approach is employed to predict the fatigue life based on the simulation results. On the whole, the most prediction results are in a factor-2 scatter band, except conservative prediction result for uniaxial path.

Key words: Mod.9Cr-1Mo steel;notched specimen;nonproportional loading;finite element analysis;fatigue life prediction