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| This paper presents a study of electric potential drops across a PKHS crack gap in piezoelectric materials. The PKHS crack was proposed by Parton and Kudryavtsev [1] and Hao and Shen [2], which accounts for the influence induced by the permittivity of medium inside crack gap upon crack tip parameters. Although many efforts have been addressed in the past 10 years, the present investigation does provide some novel features and better understandings on electric potential drops across the crack gap. Based on Stroh’s theory, an alternative technique is proposed in a compact form without any treatment of the mapping technique [3]. Different media such as air or vacuum, Silicon oil, and NaCI solution inside the crack gap are considered for comparisons, from which the influences of different permittivities of media inside the crack gap on the NCODJ and EPD across the crack gap respectively in seven kinds of piezoelectric ceramics are studied in detail. Numerical results of the normal crack opening displacement jump (NCODJ) and the electric potential drop (EPD) against the applied electric field are plotted in figures. It is found that the NCODJ for a central PKHS crack with length 2mm is always extremely small, around 1mm or 0.05% of the crack length when the mechanical loading is taken to be 20MPa and the electric field varies from –1MV/m to 1MV/m, whereas the EPD is very large, around several hundreds or more than thousand Volt. It is also found that the permittivities of media inside the crack gap influence the NCODJ and EPD significantly. |
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| Keywords:Crack,Fracture,Permittivity |
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