Elastic and Elastic-Plastic Taylor Bar cases

Two square bars with elastic and elastic-plastic material properties impact to wall. While the elastic bar bounces back with small deformation and the elastic-plastic one deforms considerably but only slightly bounces back at the last phase of collision. The smoothed particle hydrodynamics (SPH) simulations are done by using the open-source multi-physics library SPHinXsys: https://github.com/Xiangyu-Hu/SPHinXsys.