“…Theoretical investigation concerned with the problem of finding the electro-elastic field around a crack in piezoelectric material can be found in Parton (1976), Pak (1990Pak ( , 1992, Sih and Zuo (2000), Zuo and Sih (2000), Sih (2002), Landis (2004), Groh and Kuna (2005), Viola et al (2007) and others, and there have been many important achievements in this field over three decades. In the above studies several mathematic techniques have been used, such as the eigenfunction analysis, the integral transforms, the asymptotic tip analysis, the complex variable method.…”