This paper investigates the influence of crack geometry, crack-face and loading conditions, and the permittivity of a medium inside the crack gap on intensity factors of planar and non-planar cracks in linear piezoelectric media. A weakly singular boundary integral equation method together with the near-front approximation is adopted to accurately determine the intensity factors. Obtained results indicate that the non-flat crack surface, the electric field, and the permittivity of a medium inside the crack gap play a crucial role on the behavior of intensity factors. The mode-I stress intensity factors (K_I) for two representative non-planar cracks under different crack-face conditions are found significantly different and they possess both upper and lower bounds. In addition, K_I for impermeable and semi-permeable non-planar cracks treated depends strongly on the electric field whereas those of impermeable, permeable, and semi-permeable penny-shaped cracks are identical and independent of the electric field. The stress/electric intensity factors predicted by permeable and energetically consistent models are, respectively, independent of and dependent on the electric field for the penny-shaped crack and the two representative non-planar cracks. Also, the permittivity of a medium inside the crack gap strongly affects the intensity factors for all crack configurations considered except for K_I of the semi-permeable penny-shaped crack.

中文翻译：

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不同裂纹面条件下3D压电介质中裂纹的广义SIF研究

本文研究了裂纹几何形状，裂纹面和加载条件以及裂纹间隙内介质的介电常数对线性压电介质中平面和非平面裂纹强度因子的影响。采用弱奇异边界积分方程法和近前逼近法来精确确定强度因子。所得结果表明，裂纹间隙内部非平坦裂纹表面，电场和介电常数对强度因子的行为起着至关重要的作用。发现在不同的裂纹面条件下，两个代表性的非平面裂纹的I型应力强度因子（K _I）显着不同，并且具有上下限。另外，K对于非渗透性和半渗透性非平面裂纹，_I很大程度上取决于电场，而非渗透性，渗透性和半渗透性便士形裂纹的裂纹是相同的，并且与电场无关。由渗透性和能量一致性模型预测的应力/电强度因子分别独立于并取决于便士形裂纹和两个代表性非平面裂纹的电场。而且，裂缝间隙内部的介质的介电常数强烈影响所考虑的所有裂缝构型的强度因子，除了半渗透性便士形裂缝的K _I之外。