Dynamic fracture energy of polyurea-bonded steel/E-glass composite joints

Abstract

We report dynamic fracture energy measurements for E-glass/polyurea/steel joints at a peak strain rate of 1.2 × 10 7 s −1. Experiments were done by initiating a crack at the steel/polyurea interface by a laser-generated stress wave, whose profile was recorded using optical interferometry. The critical energy release rate or the energy delivered by the propagating stress wave to the crack-tip region at crack initiation was computed by using a wave dynamics simulation. An average value of 359 (±19) J/m 2 was obtained. The effect of moisture on the fracture energy values was also examined. Results showed that the values reduced by only 3% to 349 ± 19 J/m 2 in samples that were exposed to 75% RH at 65 °C for 30 days. In addition to using the data as a local failure criterion in large-scale simulation of structural joints, it can be used to estimate the residual fracture energy of the E-glass/polyurea/steel joints in service.