The finite element method (FEM)-based wheel-rail rolling contact model with a fresh wheel flat was built to investigate the wheel-rail impact responses, where a comprehensive dynamic explicit algorithm was employed. Two basic dynamic effects (i.e., inertia effect and strain-rate effect) and temperature effect during the wheel-rail sliding process were considered. Influences of train speed, flat length and axle load on the wheel-rail impact responses were discussed in terms of wheel-rail impact force, von Mises equivalent stress, equivalent plastic strain and XY shear stress. Simulation results demonstrate that the FEM-based wheel-rail rolling contact model can well describe the strong nonlinearities in geometry, contact and material. The strain rate effect contributes to elevate the maximum von Mises equivalent stress and restrain the plastic deformation. The initial thermal stress can decrease the maximum von Mises equivalent stresses and maximum XY shear stresses, but can aggravate the plastic deformation. Furthermore, the flat-induced wheel-rail impact force, von Mises equivalent stress, equivalent plastic strain and XY shear stress are revealed to be sensitive to train speed, flat length and axle load.
Part of the book: Modern Railway Engineering
Single-curvature sandwich panels combine the advantages of the shell and sandwich structure and are therefore envisaged to possess good potential to resist blast and shock or impact loads. This study presents a comprehensive report on the dynamic response and shock resistance of single-curvature sandwich panels, comprising two aluminum alloy face-sheets and an aluminum foam core, subjected to air-blast loading, in terms of the experimental investigation and numerical simulation. The deformation modes, shock resistance capability, and energy absorption performance are studied, and the influences of specimen curvature, blast impulse, and geometrical configuration are discussed. Results indicate that the deformation/failure, deflection response, and energy absorption of curved sandwich panels are sensitive to the loading intensity and geometric configuration. These results are significant to guide the engineering applications of sandwich structures with metallic foam cores subjected to air-blast loading.
Part of the book: Contact and Fracture Mechanics