Crushable polymer foam behavior at cold temperatures

Experiments were conducted to characterize and develop predictive constitutive equations for the elastic-plastic, post-yield hysteresis behavior of Divinycell H100 foam at temperatures as low as −40°C. The initial elastic modulus and yield strength of the foam increased almost linearly by about 50% as temperatures decreased from 23 to−40°C. Post-yield hysteresis, which was described by strain hardening, viscoelasticity and damage also increased as the temperature fell to −40°C, but this behavior was curtailed by a sharp reduction in tensile and shear ductility as the foam approached its ductile-to-brittle transition temperature near −50°C. An anisotropic elastic-plastic, viscoelastic damage constitutive model was extended to predict cold temperature behavior. Good agreement was found between analytical predictions and the experimental results. The temperature-dependent constitutive equation can be used in conjunction with appropriate failure criteria to predict foam-core sandwich panel behavior in cold regions.