Systematic experimental study on mechanical behavior of PVB (polyvinyl butyral) material under various loading conditions

The mechanical behavior of polyvinyl butyral (PVB) significantly influences crashworthiness and energy mitigation abilities of windshields in terms of pedestrian safety. In this article, mechanical characteristics of PVB are experimentally studied. First, tension and compression experiments on PVB specimen are carried out under various quasi-static loading rates. Fundamental mechanism of rate-dependent behavior is investigated. Besides, dynamic tension and compression experimental data are compared to investigate the mechanical behavior of PVB in a whole strain rate region and it is found that PVB behaves as a visco-elastic material under compressive loadings in both quasi-static and dynamic situations; however, in tension experiments, stressstrain curves of PVB under dynamic loadings are elasto-plastic while those under quasi-static loadings are visco-elastic. Considering all the unique characteristics of PVB's behavior, constitutive models are then established based on Zhu-Wang-Tang model mathematically. Further, unit volume energy absorption of every experiment in quasi-static tension and compression are calculated as well as the stress intensify factor. In addition, visco-elasticity part in the constitutive model is employed. Results may offer useful experiment data and important constitutive characteristics of PVB material to further studies of automotive crashworthiness and pedestrian protection. POLYM. ENG. SCI., 2012. (C) 2012 Society of Plastics Engineers