T应力对Ⅰ-Ⅱ复合型裂纹扩展的影响1.pdfVIP

第27卷第 4期 Vo1．27No．4 2010年 4 月 Apr． 2010 工 程 力 学 ENGD ER G ～匝CHANICS 5 文章编号：1000-4750(2010)04．0005．08 应力对 I—II复合型裂纹扩展的影响 赵艳华，陈 晋，张 华 (大连理工大学海岸和近海工程国家重点实验室，辽宁，大连 116024) 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 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 立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 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 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。 关键词：最大周向正应力；I．I复合型裂纹； 应力；开裂角；应力强度因子 中图分类号：0346．1 文献标识码：A INFLUENCE oF STRESS oN CRACK PRoPAGATIoN FoR I—II M IXED M oDE LoADING ZHAO Yan．hua，CHEN Jin，ZHANG Hua (StateKeyLaboratoryofCoastal andOfshoreEngineering，DalianUniversityofTechnology,Dalian，Liaoning 116024，Chma) Abstract： Maximum tensile stress(MTS)criterion iS adopted to predict brittle fracture under I—I 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．W ith an inclined crack in plates under biaxial loading，I-II mixed mode fracture with pure I mode and pure II mode included iS achieved by various combinations of vertical and horizontal loads．as wel1 as diferent angles of the internal crack to the vertical 1oad．The predicted direction for fracture initiation and I 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 kn own for a given specimen geometry．The an alysis confirms that the presence of T-stress has a significant efect on mode I—II fracture in brittle fracture for linear elastic materials，especialy for modeIIfracture． Key words： maximum tensile stress；I—II mixed mode fracture；T-stress；crack initiation angle；stress intensity