双相介质界面附近裂纹的断裂力学特征
CHARACTERS OF FRACTURE MECHANICS FOR A CRACK TIP NEAR BIMATERIAL INTERFACE
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摘要: 复合材料界面附近的力学性态对于材料的性能和强韧化影响是非常重要的。首先研究和讨论了含裂纹的双相介质的J 积分守恒定律的适用性问题, 采用有限元法证明了当裂纹平行靠近界面时, 其J 积分数值与裂纹位置无关的假设。文中建立了一种双相介质界面附近存在斜裂纹的分析模型, 用有限元和数值拟合相结合的方法, 得到了在远场单轴拉应力作用下, 斜裂纹处在不同介质中, 近界面一端裂尖的é 型能量释放率近似计算公式, 和相应的应力强度因子的计算方法。Abstract: The scope of application of the path independence of J integral in bimaterial with a crack, which is parallel or vertical or inclined to the interface, is discussed in this paper. According to the conservative law of J integral for the bimaterials with a crack paralleling the interface, a hypothesis about independence of the values of the type Ⅰ fracture strain energy release rate(SERR) from the location of the crack paralleling and closely near the interface is forwarded. And it is verified with finite element method(FFM). A schematic model for a skew crack being near the bimaterial interface is provided. The variation law of SERR with the Dundur's parameters and the angle θ between the interface and the crack surface is calculated by FEM. A method for calculating the stress intensity factor through the SERR for a skew crack near the interface is also given in the paper.