Characterization of Epoxy Resin Including Strain Rate Effects Using Digital Image Correlation System

AbstractThe mechanical response of epoxy resin Epon E 863 has been studied in tension, compression, and flexure. The epoxy resins have been tested at different strain rates ranging from 5.9×10-5 to 0.03 s-1. Two types of dog-bone geometries have been used in the tension tests. Small sized cubic, prismatic, and cylindrical samples were used in compression tests. Beams with quarter deep notches or grooves were tested at their midpoints in flexural tests. Strains were measured by using a digital image correlation technique, extensometer, strain gages, and actuator. Observation of sample geometry during tension tests at constant elongation rate shows necking and crazing in Epon E 863. Cubic, prismatic, and cylindrical compression samples undergo a stress drop at yield, but only cubic samples experience strain hardening before failure. Characteristic points of tensile and compressive stress strain relation and load deflection curve in flexure, such as proportional elastic limit stress (PEL), ultimate tensile strength (UTS), compressive yield strength (CYS), and failure strain were measured and their variations with strain rate studied.