Higher-order time domain boundary elements for elastodynamics: graded meshes and hp versions

The solution to the elastodynamic equation in exterior of a polyhedral domain or screen exhibits singular behavior from corners and edges. detailed expansion singularities implies quasi-optimal estimates for piecewise polynomial approximations Dirichlet trace traction. results are applied hp graded versions time boundary element method weakly hypersingular integral equations. Numerical examples confirm theoretical Neumann problems screens polygonal domains 2d. They exhibit expected convergence rates solutions.