Dynamic Tensile Properties of Plastics over a Wide Range of Strain Rates

Dynamic tensile properties of a variety of plastics, were studied over a wide range of strain rates from 10-2 s-1 to 103 s-1 by using the Sensing Block Type High Speed Material Testing System (SBTS). The plastics were composed of seven kinds of polycarbonate, eight kinds of polyamide, one kind of polypropylene and acrylic-butadiene-styrene (ABS). It was observed for all the tested plastics, that the flow stress at each plastic strain increased monotonically with the logarithmic strain rate, and also increased linearly over the strain rates from 0.01s-1 to 32 s-1. It was observed that the strain rate sensitivity of the flow stress of these plastics decreased monotonously with the enhanced quasi-static flow stress. These phenomena are similar to those observed frequently for many metallic materials. The plastics were classified tentatively into three groups based on the rate sensitive characteristics. The possibility of expressing these dynamic properties for each group by using Tanimura-Mimura model was discussed.