Dynamic tension of ductile polymers: Experimentation and modelling

Two main problems are recurrently mentioned when performing dynamic tension tests of polymers: The weak transmitted signal, often close to the level of the signal noise, and the (in)ability to achieve dynamic force equilibrium. In this work, we investigated the dynamic tensile response of commercial polycarbonate (PC) using the Kolsky-Bar apparatus and digital image correlation (DIC). We conducted 2D numerical simulations to explore the sensitivities of the experimental apparatus and to simulate the dynamic tests. By specifically focusing on the material behavior within the dynamically evolving neck, calibration of a stress strain curve was achieved in combination of numerical modeling. We introduce a "4-point model" that can successfully predict the location of the neck and the strain distribution along the specimens. The static tensile, dynamic tensile and dynamic compressive behavior of commercial PC are compared, and our analysis suggests a strong correlation between the three. This observation could facilitate the measurement of the dynamic tensile strength of polymers - to be possibly extracted from dynamic compression or static tension measurements only.