A Numerical Method for Solving 3D Elasticity Equations with Sharp-Edged Interfaces

Abstract EN

Interface problems occur frequently when two or more materials meet.

Solving elasticity equations with sharp-edged interfaces in three dimensions is a very complicated and challenging problem for most existing methods.

There are several difficulties: the coupled elliptic system, the matrix coefficients, the sharp-edged interface, and three dimensions.

An accurate and efficient method is desired.

In this paper, an efficient nontraditional finite element method with nonbody-fitting grids is proposed to solve elasticity equations with sharp-edged interfaces in three dimensions.

The main idea is to choose the test function basis to be the standard finite element basis independent of the interface and to choose the solution basis to be piecewise linear satisfying the jump conditions across the interface.

The resulting linear system of equations is shown to be positive definite under certain assumptions.

Numerical experiments show that this method is second order accurate in the L∞ norm for piecewise smooth solutions.

More than 1.5th order accuracy is observed for solution with singularity (second derivative blows up).