Temperature and strain rate dependent large tensile deformation and tensile failure behavior of transparent polyurethane at intermediate strain rates

Transparent polyurethane has been widely applied in laminated windshield glasses as the interlayer material to enhance the reliability due to its outstanding impact resistance. Under impact loading such as bird strike, the interlayer undergoes large tensile deformation mainly at intermediate strain rates (at the order of magnitudes from 10(0) to 10(3) , excluding 1000/s). In addition, the interlayer is on service over a wide range of temperatures for a plane traveling around the world. The mechanical behavior of transparent polyurethane under these conditions is not fully understood. In this study, systematical experiments were performed on transparent polyurethane. The viscoelasticity of the material was firstly verified by several quasi-static cyclic tests. Then a series of large tensile deformation and tensile failure experiments were conducted under intermediate strain rates and at temperatures of - 40 degrees C to 40 degrees C using a servo-hydraulic high-speed tensile machine. All strain data were acquired by the DIC technique. The experimental results show that tensile stress-strain curves and failure behaviors are significantly temperature and strain rate dependent. The rate-temperature equivalence was also observed. Finally, a phenomenological analysis of mechanical quantities of the material was carried out.