arXiv subjects

Peicheng Zhu

Publications and source records attributed to Peicheng Zhu.

8 recordsLinked to original sources

arXiv2026

Analysis validation of a new continuum model for the evolution of grain boundaries in polycrystalline materials

To describe the evolution of grain boundaries based on the underlying microscopic mechanisms of line defects (disconnections) and the integrated effects of a diverse range of thermodynamic driving forces, Zhang, et al. in 2017 formulated a continuum equation. We prove the global-in-time existence, uniqueness, and regularity of the weak solution to an initial-boundary value problem for this model. The existence, uniqueness of the stationary solution are also established. Finally, we investigate the large-time behavior of the weak solution of the evolution problem, and show that the solution converges to the stationary solution in a suitable sense. Numerical simulations are carried out to validate the analysis results. The main difficulties in the proof of main theorems are due to a non-local term with singularity, a non-smooth coefficient of the highest derivative associated with the gradient of the unknown, and the special form of free energy which is not uniformly bounded from below. The key ingredients in the proof are the energy method, an estimate for a singular integral of the Hilbert type, Fourier transform of Hilbert transformations, and an estimate with a weight, for time-derivative of the unknown.

math.AP↗

arXiv2022

Weak solutions to an initial-boundary value problem for a continuum equation of motion of grain boundaries

We investigate an initial-(periodic-)boundary value problem for a continuum equation, which is a model for motion of grain boundaries based on the underlying microscopic mechanisms of line defects (disconnections) and integrated the effects of a diverse range of thermodynamic driving forces. We first prove the global-in-time existence and uniqueness of weak solution to this initial-boundary value problem in the case with positive equilibrium disconnection density parameter B, and then investigate the asymptotic behavior of the solutions as B goes to zero. The main difficulties in the proof of main theorems are due to the degeneracy of B=0, a non-local term with singularity, and a non-smooth coefficient of the highest derivative associated with the gradient of the unknown. The key ingredients in the proof are the energy method, an estimate for a singular integral of the Hilbert type, and a compactness lemma.

math.AP↗

arXiv2011

Solvability via viscosity solutions for a model of phase transitions driven by configurational forces

In the present article, we are interested in an initial boundary value problem for a coupled system of partial differential equations arising in martensitic phase transition theory of elastically deformable solid materials, e.g., steel. This model was proposed and investigated in previous work by Alber and Zhu in which the weak solutions are defined in a standard way, however the key technique is not applicable to multi-dimensional problem. Intending to solve this multi-dimensional problem and to investigate the sharp interface limits of our models, we thus define weak solutions in a different way by using the notion of viscosity solution, then prove the existence of weak solutions to this problem in one space dimension, yet the multi-dimensional problem is still open.

math.DS↗

arXiv2011

Existence and regularity of weak solutions to a model for coarsening in molecular beam epitaxy

Taking into account the occurrence of a zero of the surface diffusion current and the requirement of the Ehrlich-Schwoebel effect, Siegert et al \cite{Siegert94} formulate a model of Langevin type that describes the growth of pyramidlike structures on a surface under conditions of molecular beam epitaxy, and that the slope of these pyramids is selected by the crystalline symmetries of the growing film. In this article, the existence and uniqueness of weak solution to an initial boundary value problem for this model is proved, in the case that the noise is neglected. The regularity of the weak solution to models, with/without slope selection, is also investigated.

math.DS↗

arXiv2011

Regularity of solutions to a model for solid-solid phase transitions driven by configurational forces

In a previous work, we prove the existence of weak solutions to an initial-boundary value problem, with $H^1(Ω)$ initial data, for a system of partial differential equations, which consists of the equations of linear elasticity and a nonlinear, degenerate parabolic equation of second order. Assuming in this article the initial data is in $H^2(Ω)$, we investigate the regularity of weak solutions that is difficult due to the gradient term which plays a role of a weight. The problem models the behavior in time of materials with martensitic phase transitions. This model with diffusive phase interfaces was derived from a model with sharp interfaces, whose evolution is driven by configurational forces, and can be thought to be a regularization of that model. Our proof, in which the difficulties are caused by the weight in the principle term, is only valid in one space dimension.

math.DS↗

arXiv2011

Spherically symmetric solutions to a model for phase transitions driven by configurational forces

We prove the global in time existence of spherically symmetric solutions to an initial-boundary value problem for a system of partial differential equations, which consists of the equations of linear elasticity and a nonlinear, non-uniformly parabolic equation of second order. The problem models the behavior in time of materials in which martensitic phase transitions, driven by configurational forces, take place, and can be considered to be a regularization of the corresponding sharp interface model. By assuming that the solutions are spherically symmetric, we reduce the original multidimensional problem to the one in one space dimension, then prove the existence of spherically symmetric solutions. Our proof is valid due to the essential feature that the reduced problem is one space dimensional.

math.DS↗

arXiv2009

Stationary waves to viscous heat-conductive gases in half space: existence, stability and convergence rate

The present paper is concerned with large-time behavior of solutions to an outflow problem for an ideal polytropic model of compressible viscous gases in one-dimensional half space, and with a convergence rate of solutions toward a corresponding stationary solution. With the aid of center manifold theory, we prove the existence of the stationary solution, under a smallness condition on the boundary data. We also investigate, by employing an energy method, the time asymptotic stability of the stationary solution under suitable smallness assumptions, and estimate the convergence rate which coincides with the spatial decay rate of the initial perturbation. The proof is mainly based on a priori estimates, which are derived by a time and space weighted energy method.

math.AP↗

arXiv2009

Traveling waves for models of phase transitions of solids driven by configurational forces

This article is concerned with the existence of traveling wave solutions, including standing waves, to some models based on configurational forces, describing respectively the diffusionless phase transformations of solid materials, e.g., Steel, and phase transitions due to interface motion by interface diffusion, e.g., Sintering. These models are recently proposed by Alber and Zhu. We consider both the order-parameter-conserved case and the non-conserved one, under suitable assumptions. Also we compare our results with the corresponding ones for the Allen-Cahn and the Cahn-Hilliard equations coupled with linear elasticity, which are models for diffusion-dominated phase transformations in elastic solids.

math.AP↗