A COMPARISON OF ENERGY ABSORBING CAPABILITIES OF PAPER AND STEEL STRUCTURES SUBJECTED TO PROGRESSIVE FAILURE UNDER FREE FALLING OBJECTS

An inverted paper cup of 0.26 mm thickness was subjected to deformationunder a freely falling steel ball at a velocity of 2.77 m/sec. The deformedfeatures of the paper cup were measured. The dynamic loading event wassimulated using piecewise linear plasticity material model in LSDYNA.Deformed shape of the paper cup in finite element model matched closely withexperimental results with ignorable small discrepancies. The paper cup was ableto absorb all the kinetic energy of the falling steel ball for the above mentionedfalling speed and the ball did not bounce out of the cavity generated by theimpact. In LSDYNA a similar size steel cup was also subjected to a freelyfalling ball with same speed and the energy absorbed was compared to theenergy absorbed by the paper cup. It was found that under similar conditions apaper cup would undergo a significant progressive failure and absorb all theenergy of the falling object.