【摘要】 针对拉扭多轴疲劳加载情况,分析最大剪切平面上的应变特性。利用临界损伤平面原理确定不同加载参数下的临界损伤平面,在此基础上提出一种基于单轴疲劳材料常数和高温蠕变特性的高温多轴疲劳寿命预测模型。利用高温合金材料GH4169薄壁管疲劳试样在控制应变拉扭循环加载下的试验数据,对所提出的寿命模型进行验证。结果表明,在高温低周拉扭循环加载下,所提出的高温疲劳寿命预测模型可以较好地预测高温疲劳寿命。更多还原

【Abstract】 The characteristics of strains on the maximum shear plane were analyzed under tension-torsion multiaxial fatigue loading. The critical damage planes were determined by the critical plane principle under different loading parameters. On the basis of the uniaxial fatigue constants at high temperature, a multiaxial fatigue damage parameter was proposed to calculate the pure fatigue damage. The half of maximum equivalent amplitude is used as the creep stress to calculate creep damage. Hence, a linear multiaxial creep-fatigue life prediction model was proposed to predict the creep-fatigue life at high temperature. The multiaxial fatigue data for thin tubular specimens made by a high supperalloy GH4169 were used to verify the proposed multiaxial fatigue life prediction model under proportional and non-proportional loading at high temperature. The results shown that the proposed multiaxial fatigue life prediction model can accurately predict multiaxial creep-fatigue life at high temperature. The error is within a factor of 2.更多还原