Macrocrack-microcrack interaction in piezoelectric materials, Part II: Numerical results and discussions

Numerical results are shown in figures and tables. The major features for t he traditional stress intensity factors and the electric displacement inten sity factor against the microcrack location angle and the distance of the m icrocrack center from the macrocrack tip are discussed. It is shown that, u nlike single-crack problems, the mechanical loading and the electric loadin g are coupled together since the microcrack not only releases the near-tip stresses, but also disturbs the near-tip electric field. Furthermore, the i nfluence of the electric loading on the mechanical strain energy release ra te (MSERR) at the microcrack tip is discussed in detail. It is found that t he variable nature of the MSERR parallel microcrack is located near the mac rocrack tip. However, the slope of the MSERR's curve considering microcrack ing diverges far from the those without considering microcracking. This fin ding reveals that besides the two sources of microcrack shielding discussed by Hutchinson (1987) for brittle solids, the disturbances of the near-tip electric field due to microcracking really provides another source of shiel ding for piezolectric solids.