残留应力对倾斜裂纹的变形和曲折特性的影响  

Effect of compressive residual stress around slant crack to bending fatigue crack propagation behavior

作　　者：马有理[1] 朱琳[2] 

机构地区：[1]哈尔滨商业大学能源与建筑工程学院,哈尔滨150028 [2]哈尔滨商业大学轻工学院,哈尔滨150028

出　　处：《哈尔滨商业大学学报（自然科学版）》2011年第4期633-637,共5页Journal of Harbin University of Commerce：Natural Sciences Edition

基　　金：黑龙江省自然科学基金项目(E201057)

摘　　要：对于具有中心孔的混合型条件下的预裂纹,提出了用沿着裂纹的不连续位移量来直接计算裂纹的Ⅰ型和Ⅱ型应力扩大系数(KⅠ)mes和(KⅡ)mes的方法.进而讨论了疲劳预裂纹周围的残留应力对其自身变形行为的影响.通常情况下利用最大切向应力法则和以上计算的应力扩大系数可以预测裂纹的继续扩展方向.使用矩型板中的倾斜角度为β=45°的疲劳裂纹和退火裂纹分别进行了曲折疲劳裂纹的扩展实验.其结果是,回火预裂纹的情况下,实验测得的曲折角度θmes与计算所预测的曲折角度θest基本上相一致;但对于疲劳预裂纹,由于预裂纹周围的压缩残留应力的影响,θmes的值比θest要大.For pre-cracks with a center-hole notch under mixed-mode conditions,a method is proposed in which mode Ⅰ and mode Ⅱ stress intensity factors（KⅠ）mes and（KⅡ）mes can be directly evaluated from the discontinuous displacement along a crack.The effect of compressive residual stress on fatigue pre-crack deformation behavior was discussed.In general,using the biggest tangential stress criterion the direction propagating from the pre-cracks can be predicted by（KⅠ）mes and（KⅡ）mes.Then testing for bending fatigue crack propagation under mixed-mode conditions was carried out using fatigue and annealed slant pre-cracks with slant angles β=450 in a rectangular plate.As a result,for annealed pre-crack,the estimated fracture angle θest corresponded to the measured one θmes;On the other hand,for fatigue pre-crack,θmes was bigger than θest because of the compressive residual stress around the pre-crack.

关 键 词：混合型 不连续变位量 压缩残留应力 曲折角度 疲劳(回火)预裂纹 

分 类 号：TU51[建筑科学—建筑技术科学]