Low temperature brittle debond damage under normal compression of sandwich plates: Analytical modeling and experimental validation

Experimental study and analytical modeling of brittle debond damage formation in polymethacrylimide (PMI) foam sandwich plates under slow normal compression are reported in this paper. The major cause of damage formation under quasi static compression is found to be low temperature brittle cracking effects taking place below some critical temperature levels within the range from −20 °C to −30 °C. The magnitude of critical temperature is increasing as the displacement controlled loading speed increases. The maximal strain achieved during the compression phase is found to be less influential, however it still significantly affects the shape and size of damage. The phenomenon is described in terms of the theory of thin elastic plates (beams) on a piece-wise linear foundation of Kelvin–Voight type. In particular, exact analytical solutions are derived to describe the damage formation. The dependence of the corresponding load on effective strain reveals a jump of slope at yielding point, which is in perfect match with experimental observations.