elements(1).dat materials(1).dat nodes(1).dat check_mesh_3D.m FEA_field_plot_3D.m Gaussian_quadrature_3D.m hw1.m linear_elasticity_3D.m master_element_linear_elasticity_3D.m plot_mesh.m post_processing_3D.m deformed mesh.png bcsdisp(1).dat bcsforce(1).dat bcstraction(1).dat