Mechanical Performance Degradation of Glass Fiber-reinforced Polyurethane Foam Subjected to Repetitive Low-energy Impact

Abstract Polyurethane foam (PUF) has excellent thermal insulation performance owing to its closed cellular solid structure. Additionally, this microstructural characteristic provides outstanding impact absorption performance. Owing to these advantages, PUF is widely adopted in transportation applications. From the viewpoint of use in practical applications, it is necessary to evaluate the residual strength after repetitive low-energy impacts on the structure. Thus, in the present study, we investigated the effects of repetitive low-energy impact on mechanical behavior of glass fiber-reinforced PUF. After the free-falling type repetitive impact test, a series of compressive tests were performed to investigate the effect of impact conditions on the compressive performance. As a result, the critical impact energy causing degradation of the impact and compressive performance of the material was 1,092 - 1,228 J/m2. In the impact performance, the peak stress, impact duration, and peak strain decreased by 13.5%, increased by 28.5%, and increased by 35.2%, respectively, after 80 repetitions of a 1,500 J/m2 impact. Moreover, under the same impact condition, the elastic modulus of the material decreased by 44.5% compared to that of the intact specimen.