Influence of inclined electric fields on the effective fracture toughness of piezoelectric ceramics
Influence of inclined electric fields on the effective fracture toughness of piezoelectric ceramics
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DOI：
10.1007/s00707-014-1190-5
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发表时间：
2015-02
期刊：
影响因子：
2.7
通讯作者：
A. Ricoeur;R. Gellmann;Zhibin Wang
中科院分区：
文献类型：
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作者：
A. Ricoeur;R. Gellmann;Zhibin Wang
电场在不同尺度上影响铁电体的断裂行为。在原子尺度上，共价键中的力受到影响。在细观尺度上，铁电畴壁运动可以屏蔽裂纹尖端或导致附加载荷。基于经典方法，在宏观尺度上，电场对能量释放率和电位移强度因子有主要影响；但对机械应力强度因子影响不大。如果在裂纹尖端加载分析中考虑由于介电性能跳变而导致的裂纹表面麦克斯韦应力，情况就不同了。首先，一般考虑的问题是如何制定一个包含所有三个尺度的断裂标准。在宏观尺度上，研究了任意倾斜电场对裂纹临界力学载荷的影响。扩展模型特别揭示了平行于裂纹面电场的意义。采用一种结合解析-数值的方法来求解固体介质和裂纹介质的耦合两域问题，即使在倾斜电场中也支持已建立的电容方法。
Electric fields effectuate the fracture behavior of ferroelectrics on different scales. On the atomic scale, forces in covalent bonds are influenced. On the mesoscopic scale, the ferroelectric domain wall motion shields the crack tip or leads to an additional loading. Based on classical approaches, on the macroscopic scale, the electric field has a major impact on the energy release rate and the electric displacement intensity factor; however, it scarcely influences the mechanical stress intensity factors. The situation is different if Maxwell stresses at crack faces, as a consequence of the jump of dielectric properties, are incorporated in the crack tip loading analysis. First, general considerations deal with the question how a fracture criterion has to be formulated, incorporating all three scales. On the macroscopic scale, the influence of an arbitrarily inclined electric field on the critical mechanical crack loading is investigated. The extended model, in particular, reveals the significance of electric fields parallel to the crack faces. A combined analytical–numerical approach is applied to solve the coupled two-domains problem of solid and crack dielectric, supporting the well-established capacitor approach even for inclined electric fields.