The most efficient improved zigzag theory (IZIGT) is applied to obtain the interlaminar stresses for the levy-type piezoelectric and hybrid sandwich plates. The accuracy of these interlaminar stresses near the arbitrary support conditions is assessed by comparing the results with that of its smeared counterpart improved third order theory (ITOT) and recently developed three dimensional pdimensional solutions using the three dimensional extended Kantorovich method (3D EKM). Results are presented both for pressure and potential loading case. It is observed that for both the mechanical (normal and shear stresses) and the electrical variables (electric displacements, electric potential) predicted by IZIGT are not accurate in the close vicinity of clamped/free supports whereas ITOT predicits inferior results as compared to IZIGT. Both IZIGT and ITOT over predict the stresses under pressure loading case whereas under potential loading, the stresses are under predicted by these theories neaer or at the clamped/free/simply supported edges.

Keywords: Extended kantorovich method, Zigzag theory, 3D piezoelasticity, Boundary layer effect.