摘要
利用最大周向正应力判据MTS重新分析研究了脆性破坏的Ⅰ-Ⅱ复合型裂纹扩展,其中考虑了平行于裂纹方向的非奇异项T应力。以平板中的斜裂纹处于双向受力为研究对象,通过两个方向力的不同组合以及裂纹与受力方向的夹角变换得到包括纯I型和纯II型在内的Ⅰ-Ⅱ复合型裂纹,分析了T应力对裂纹扩展方向以及断裂时的应力强度因子的影响,并将预测结果与现有的实验数据进行了比较。在此基础上,给出了不同T应力条件下通用的Ⅰ-Ⅱ复合型裂纹扩展条件,可用于给定几何试件的脆性断裂判定。分析结果表明:裂纹尖端非奇异项T应力对裂纹扩展的影响是不可忽略的,尤其是对II型断裂的影响更为明显。
Maximum tensile stress （MTS） criterion is adopted to predict brittle fracture underⅠ-Ⅱ mixed mode conditions, wherein the effect of the non-singular term of stress, often known as the T-stress on the angle of initiation and the onset of crack growth are explored. With an inclined crack in plates under biaxial loading, Ⅰ-Ⅱmixed mode fracture with pure Ⅰ mode and pure Ⅱ mode included is achieved by various combinations of vertical and horizontal loads, as well as different angles of the internal crack to the vertical load. The predicted direction for fracture initiation andⅠ-Ⅱ mixed mode stress intensity factors are compared with some earlier experiment results. Consequently, a general condition for predicting Ⅰ-Ⅱ mixed mode fracture under various T-stresses is provided to predict the brittle fracture when the stress intensity factors for Ⅰ mode and Ⅱ mode as well as the T-stress at the crack tip are known for a given specimen geometry. The analysis confirms that the presence of T-stress has a significant effect on modeⅠ-Ⅱ fracture in brittle fracture for linear elastic materials, especially for mode Ⅱ fracture.
出处
《工程力学》
EI
CSCD
北大核心
2010年第4期5-12,共8页
Engineering Mechanics
基金
国家自然科学基金项目(50708014
E080501)
关键词
最大周向正应力
Ⅰ-Ⅱ复合型裂纹
丁应力
开裂角
应力强度因子
maximum tensile stress
Ⅰ-Ⅱ mixed mode fracture
T-stress
crack initiation angle
stress intensity factor
