244 Effect of Strain Rate on Yield Stress of Poly(L-lactic acid)

Abstract

The compressive and tensile properties of poly(L-lactic acid) (PLLA) were measured using a universal testing machine and the influence of strain rate on the compressive properties of PLLA were examined using a split Hopkinson pressure bar method. We determined constants of Drucker-Prager yield criterion for PLLA, and drew the yield curves in the plane stress space and in the second deviatoric stress invariant-first invariant of stress. The compressive yield stress of PLLA increased with an increase in the strain rate, but PLLA caused the brittle fracture in the dynamic compressive examination.