裂纹表面接触对混合型应力下倾斜疲劳裂纹变位特性的影响  

Effect on Deformation Behavior of Slant Fatigue Crack under Mixed-Mode Condition due to Contact of Crack-surface

作　　者：马有理[1] 黎庆[2] 

机构地区：[1]哈尔滨商业大学轻工学院,哈尔滨150028 [2]黑龙江省石油化学研究院,哈尔滨150040

出　　处：《金属热处理》2007年第z1期394-397,共4页Heat Treatment of Metals

摘　　要：在循环载荷的作用下由中心孔向两端延伸所产生的倾斜裂纹,当载荷的应力比变化(从R=0到R=-1)时裂纹面的凸凹程度也会随之变化。对于倾斜角度比较小的疲劳裂纹(β=45°),讨论了上述的应力比所制作的裂纹其周围的压缩残留应力对Ⅰ型应力扩大系数(K_Ⅰ)_(mes)以及裂纹上下表面的相互接触对Ⅱ型应力扩大系数(K_Ⅱ)_(mes)的影响。其结果是,应力比R=0和R=-1的疲劳裂纹,应力扩大系数的实验值(K_Ⅰ)_(mes)都小于理论值K_Ⅰ,且R=-1的(K_Ⅰ)_(mes)比R=0的值大。而对于Ⅱ型应力扩大系数,虽然两者的实验值(K_Ⅱ)_(mes)也都小于理论值K_Ⅱ,但R=-1的(K_Ⅱ)_(mes)比R=0的值下降的更多。For slant cracks with a center-hole notch making under cyclic loading,the shape of the crack surface will be different as the stress ratio is changing.Using the slant cracks with smaller slant angle ofβ=45 deg,the effect on modeⅠstress intensity factor (K_Ⅰ)_(mes) and modeⅡstress intensity factor(K_Ⅱ)_(mes) due to the compressive residual stress and the crack surface contact were discussed.As a result,the measured stress intensity factor(K_Ⅰ)_(mes) is smaller for both fatigue cracks making under stress ratio of R=0 and R=-1 than the theoretical,and the value of (K_Ⅰ)_(mes) from the crack of R=-1 is bigger than the one from R=0.On the other hand,for modeⅡstress intensity factor,(K_Ⅱ)_(mes) measured from both fatigue cracks of R=-1 and R=0 is also reduced than the theoretical,but the (K_Ⅱ)_(mes) from the crack of R=-1 is lower than the value from R=0.

关 键 词：残留应力 疲劳裂纹 回火裂纹 不连续变位 应力扩大系数 

分 类 号：TG15[金属学及工艺—热处理]