In-plane biaxial crushing of honeycombs—: Part II: Analysis

The in!plane biaxial crushing experiments on polycarbonate honeycomb presented in Part I are simulated using large scale _nite element models[ The models account for nonlinearities in geometry and due to contact while the polycarbonate is modeled as an elastic!powerlaw viscoplastic solid[ Full!scale simulations of the uniaxial crushing of this honeycomb were shown in the past to reproduce experiments with accuracy[ In biaxial crushing\ it was not practical to model specimens the same size as those in the experiments due to computational limitations^ instead\ a smaller model with 09 00 cells was adopted[ Results from simulations of seven of the crushing experiments in Part I with various biaxiality ratios are presented[ Through parametric studies it is demonstrated that the size of the specimen and friction between the specimen and the loading surfaces a}ect the initial elastic parts of the stress displacement responses and the onset of instability[ By contrast\ for average crushing strains higher than approximately 09)\ their e}ect was relatively small and the calculated responses were in good agreement with the experimental ones[ As a consequence\ the energy absorption capacity was predicted to good accuracy for all biaxiality ratios[ In addition\ many of the modes of cell collapse seen in the experiment are reproduced in the simulations