Material Properties: Mechanical behavior of glass-fiber reinforced thermoplastic materials under high strain rates

Glass-fiber reinforced polypropylene (PP) and polybutene-1 (PB-1) materials were investigated in a high-speed tensile test. The glass-fiber content of the materials and the strain rate were varied in the range between 0 and 40 wt.-% and 0.007 and 174 s-1, respectively. The aim of the investigations was to show in which way the glass-fiber content, and especially the strain rate, influence the material behavior, in this case the stress-strain behavior, the tensile strength and the fracture appearance. The strain-rate dependent material behavior is described with the phenomenological G'Sell-Jonas model. It was found that a transition from isothermal to adiabatic behavior occurs and, therefore, two different regression parameter sets are necessary to describe the material behavior accurately. An increase of tensile strength could be found for the PP and PB-1 materials examined with increasing strain rate. This behavior is described in the literature as positive strain-rate dependence.