Deformation and failure mechanisms of sandwich beams under three-point bending at elevated temperatures

Quasi-static three-point bending tests at different temperatures were carried out for sandwich beams with aluminum face sheets and closed-cell aluminum foam core. The deformation and initial failure behaviors were explored and of the three potential failure modes, i.e. core shear, indentation and face yielding, only the latter two were observed in the experiments at different temperatures. Failure mechanism maps which illustrate the dominant initial failure mode for practical beam designs were constructed for different test temperatures based on the modified Gibson model. It was found that upon increasing the temperature, the incidence of face yield mode increases and the incidence of core shear mode decreases. The theoretical predictions of the initial failure modes and limit loads according to the modified Gibson model are found to be in good agreement with the experimental results at different temperatures.