In this paper is proposed a dislocation emission mechanism for microcrack initiation
at the tip of a finite rigid conducting line in a piezoelectric solid. When a finite rigid
conducting line is embedded in a piezoelectric matrix, because of the highly
concentrated stress and electric displacement fields at its tips, dislocations of one sign
are driven away from the tip, while the stationary dislocations of the opposite sign
are left behind. As a result, a micro Zener–Stroh crack is initiated at each tip for
the in-plane case, and two microcracks at each tip for the anti-plane case.
We obtain analytical solutions of both in-plane and anti-plane extension
forces for microcracks initiated at the tip of a finite rigid conducting line. By
obtaining the stress and electric displacement fields at the tip under nonzero net
Burgers vectors, we observe two critical crack lengths. We find that the
in-plane and anti-plane critical extension forces for a finite rigid conducting
line are related to those for a conventional crack in the same piezoelectric
materials.
Keywords
Zener–Stroh crack, rigid line, mechanical strain energy
release rate, stress and electric displacement (SED)
intensity factors, piezoelectric material