摘要
对不同取向、带应力集中状态下镍基单晶合金构件的低周疲劳寿命进行了研究。在理论应力集中系数和载荷比确定的前提下,只要确定了缺口根部的剪应力范围,在不考虑分散性的情况下,缺口试棒的寿命是确定的。而此时,光滑试棒也一定存在某一个应力水平,在该应力水平下光滑试棒与缺口试棒的寿命相等;这时等寿命的光滑试棒与缺口试棒的最大剪应力范围之间存在一定的关系。根据这种关系,本文建立了剪应力范围的修正系数法,其与试验所得到的不同取向缺口试棒的低周疲劳寿命之间的最大偏差倍数为3.45,而直接采用光滑试棒剪应力范围寿命公式与实验寿命之间的最大偏差倍数为1681倍。结果表明,采用剪应力范围修正系数法预测不同取向的缺口试棒低周疲劳寿命具有较高的精度。
Low-cycle fatigue life of single crystal material component at different orientations and stress concentration state are studied.On the premise that once the theoretical stress concentration coefficient and the load ratio are determined,it is only need to determine the shear stress range in the notch root,without considering the scattering,the test bar’s life should be determined.For this life,there must be a stress level for a smooth test bar,which makes the smooth test bar’s life is equal to that of the notched test bar in this stress level.At this time,there exists some relationship between the maximum shear stress range for smooth and notched test bars with equal life.According to this relationship,a modified coefficient method based on shear stress range has been established.By contrasting the obtained low-cycle fatigue life for notched bar in different orientations by experiment method and shearing stress correction factor method,it can be found that the maximum deviation multiple is 3.45,compared to using model 1 directly,whose maximum deviation multiple is 1681,the prediction accuracy improved obviously.
出处
《应用力学学报》
CAS
CSCD
北大核心
2013年第2期273-277,308-309,共5页
Chinese Journal of Applied Mechanics
关键词
单晶
低周疲劳
多轴疲劳
滑移系
应力集中
single crystal,low-cycle fatigue,multiaxial fatigue,slip system,stress concentration
