Search

In the current paper, a macroscopic model is proposed to simulate the hysteretic dynamics of ferroelectric ceramics with creep phenomenon incorporated. The creep phenomenon in the hysteretic dynamics is attributed to the rate-dependent characteristic of the polarisation switching processes induced in the materials. A non-convex Helmholtz free energy based on Landau theory is proposed to model the switching dynamics. The governing equation of single-crystal model is formulated by applying the Euler–Lagrange equation. The polycrystalline model is obtained by combining the single crystal dynamics with a density function which is constructed to model the weighted contributions of different grains with different principle axis orientations. In addition, numerical simulations of hysteretic dynamics with creep phenomenon are presented. Comparison of the numerical results and their experimental counterparts is also presented. It is shown that the creep phenomenon is captured precisely, validating the capa...

In the present study, a mathematical model is developed to analyze the wave propagation processes in shape memory alloy rods. The first order phase transformations and associated thermo-mechanical coupling effects are accounted for by employing the modified Ginzburg-Landau-Devonshire theory. The effect of internal friction is considered by using a Rayleigh dissipation term. Chebyshev collocation method is employed together with the backward differentiation methods for numerical analysis. Numerical experiments are performed. Wave propagations caused by impact loadings are analyzed for different initial temperatures. It is demonstrated that thermal waves will be induced. Phase transformations in the material will complicate their propagation patterns. Dissipation effects are enhanced by internal friction, while dispersion during wave propagations is induced by interfacial energy term.