Mechanical behaviour in shear and compression of polyurethane foam at elevated temperature

This paper presents an experimental investigation about the effect of elevated temperature on the mechanical properties of two polyurethane (PUR) foams, with densities of 40 kg/m3 and 93 kg/m3. The experimental campaign included shear and compressive tests over a temperature range of 20°C–200°C, performed to assess the degradation of the mechanical properties of the PUR foams with temperature. To validate the diagonal tension shear test method adopted in this investigation, a numerical study was also performed, namely to assess the (shear) stress state developed within the foam. The results obtained validated the adopted test procedures, showing that the compressive and shear responses are strongly affected by elevated temperature, due to the softening of the polymeric material when it undergoes the glass transition process. For the temperature range considered in this study, both strength and modulus in shear and compression present an approximately linear reduction with temperature.