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A flat annular interfacial crack between dissimilar magnetoelectroelastic layers subjected to magnetoelectroelastic loads is investigated under the boundary condition of magnetoelectrically impermeability on the crack surface. Using the Hankel transform technique, the mixed boundary value problem is reduced to a system of singular integral equations. The integral equations are further reduced to a system of algebraic equations with the aid of Jacobi polynomials. The field intensity factor and energy release rate are determined. Numerical results reveal the effects of electric or magnetic loadings and material parameters of composites on crack propagation and growth. The results seem useful for the design of magnetoelectroelastic composite structures and devices of high performance.

The dynamic response of an annular interfacial crack between dissimilar piezoelectric layers subjected to mechanical and electrical impact loadings is investigated. Laplace and Hankel transforms are employed to reduce the mixed boundary value problem to Cauchy singular integral equations. The integral equations are further reduced to a system of algebraic equations with the aid of Jacobi polynomials. The dynamic field intensity factors and dynamic energy release rates are determined. Numerical results reveal the effects of crack configuration, electrical impact loading on crack propagation, and growth.

In this paper, the typical U-shaped pieces were taken as the object of study and the finite element numerical simulation software Dynaform is applied to simulate the effect of sheet metal bending. The U-shaped bending spring back and its thickness change are analyzed. The influence law of main parameters of die structure to sheet thickness change and the spring back amount are obtained by combining with the orthogonal analysis method. Finally a set of the optimal parameter combination is found, the spring back of U-shaped piece and the change of the thickness are controlled in a reasonable range.