Determination of Traction Separation Curve for Copper Using Essential Work of Fracture (EWF) Approach

Abstract

The essential work of fracture concept has become very popular to characterize the plane stress toughness of ductile material. The essential work characterizing the resistance of a structure to ductile fracture is important for many applications, from structural design to impact protection. The main objective of the present work is to experimentally derive the traction separation curve also known as cohesive law for copper (UNS C11040) under plane stress condition. To this end a double edge notched tension (DENT) specimens of thickness 1.5 mm were prepared. The ligament of the specimens varied between 6 to 24 mm and each specimen was tested under displacement controlled loading rate of 0.5 mm/min using miniature tensile tenting machine with a load cell capacity of 20 KN. The load displacement data were recorded and the traction separation curve was derived using normalization process suggested by Cottrell et al., 2005. The area under the traction separation curve is believed to the specific essential work of fracture and this fact was further confirmed from the experiments.