Temperature and strain rate dependent tensile behavior of a transparent polyurethane interlayer

During airplane related accidents, the transparent polyurethane interlayer is finding new applications in the aircraft protection as an interlayer of windshield to enhance structural survivability under impact loading. Using dynamic mechanical analysis, Instron testing system and low impedance Split Hopkinson Tension Bar (SHTB), dynamic tensile response of a transparent polyurethane interlayer is studied experimentally under wide ranges of strain rates and temperatures. Based on the constitutive theory and the experimental data, thermal-viscoelastic Zhu-Wang-Tang (ZWT) constitutive model is employed to describe the tensile response of the polyurethane interlayer. The experimental results also reveal the time-temperature equivalence relation for the polyurethane interlayer. Strain rate and temperature are put together to a unified parameter by introducing a dimensionless parameter, and a unified curve reflecting the time-temperature equivalence relation is obtained. (C) 2014 Elsevier Ltd. All rights reserved.