The micro-scale adhesive contact behavior of a spherical rigid punch on a piezoelectric half-space is investigated in this paper. The governing equations describing the adhesive contact behavior are obtained by using the Maugis-Dugdale (M-D) elastic adhesive contact theory [J. Colloid Interface Sci. 150 (1992) 243]. The solutions for indentation of piezoelectric materials and for elastic adhesive contact can be reduced from the present results in the absence of adhesion effect and piezoelectric effect, respectively. The effect of the electric load on the adhesive contact behavior is analyzed. It is shown that the piezoelectric effect has a significant effect on the adhesive contact behavior of piezoelectric materials. The obtained results will be helpful to understand the micro-indentation properties of piezoelectric materials.

A micromechanics model is presented for estimating the effective thermoelastic properties of layered media. The continuity condition across a perfectly bonded interface between two dissimilar materials is introduced by decomposing the stress and strain tensors into two orthogonal complementary parts, an interior part and an exterior part that are tangential and normal to the interface, respectively. This model follows from the fact that the exterior part of the stress tensor and the interior part of the strain tensor are each continuous across the perfect interface. Thereby, the interaction between different phases of composites is accounted for. The exact expressions for the effective thermoelastic properties of layered media are derived, and the connections between the present scheme and some conventional micromechanics models are examined.

Some closed-form equations for the coupling problem of buckling and growth of circular delamination are derived by recourse to the moving boundary variational principle The axisymmetric buckling of a circular delamination subjected to an equal bi-axial compression is analysed by using high-order perturbation expansion The axisymmetric buckled delamination has the following properties: under a certain residual pressure, there exist two characteristic radii, namely the critical radius Rc and growing radius Rg; for a certain interface toughness, the blister has three configuration of stationary, stable growth and unstable growth with increasing the loads Under a higher edge thrust, the nonaxisymmetric secondary buckling will occur on the base of axisymmetric buckling and then the toughness and the driving force of the interface crack will be different along the delamination front. So the growth of circular delamination will not be self-similar. Without any assumption regarding the delamination front, the cogfigurations of the blister with several nonaxisymmetric buckling modes n=2, 3, 6, 8, are simulated. The nonaxisymmetric growth process for the nonaxisymmetric buckling mode n=2 is simulated also under a sequence of loads.

A triggering criterion is suggested to determine the instability of a dislocation source under Mode-I singular stresses. Two kinds of configurations are considered, including a crack and a wedge formed by climbing dislocations pileup. Numerical results are given and discussed for both the cases.