TY - CONF A1 - Müller, Philipp A1 - Unger, Jörg F. T1 - Waves in inhomogeneous meshes N2 - Elastic waves in inhomogeneous meshes avoiding numerical artifacts Elastic waves in solids resulting from damage processes, e.g. microcracking are used to monitor the integrity of structures. The numerical modelling of these acoustic Emission processes is hindered by the different scales involved. Crack opening is a fast process and the size of the damaged zone is small, leading to small time steps and fine meshes in a numerical finite element simulation. On the other hand the relevant wave Propagation takes place on a much larger spatial scale, e.g covering the distance between Emission source and sensor. To avoid numerical oscillations, the mesh size at the emission source has to be coupled to its time scale. Using higher order spectral elements can be beneficial with respect to the needed number of degrees of freedom. To make the computation of an acoustic emission process feasible one is lead to coarsening the mesh for larger distances to the source. Solution components with a higher frequency will be reflected at mesh density steps. The mesh coarsening has to be done in a way to avoid or minimize this kind of reflections. To get more insight into the propagation characteristics of the numerical solution, dispersion curves are calculated for different element types assuming a structured mesh with constant element size. Coupling two meshes with different mesh densities will then lead to frequency dependent reflections at the boundary similar to the coupling of different materials. The starting mesh density is dictated by the acoustic emission source time scale. The largest allowable mesh size needs to resolve the components of propagating signal with the highest frequency, smallest wavelength which is given by the bandwidth of the sensor. Still coarser meshes may be used when high frequency components are propagated by a different method. T2 - COMPDYN 2019 CY - Crete, Greece DA - 24.06.2019 KW - FEM KW - Waves KW - Dispersion PY - 2019 AN - OPUS4-48582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -