Determination of Johnson-Cook damage model constants for commercial pure copper sheet by tensile testing on notched specimens

Nowadays, damage models are used to simulate and predict the failure occurrence regions in manufacturing processes. One of the most famous models that is widely used in finite element commercial codes is Johnson-Cook damage model. The aim of the present research is to determine the constants of Johnson-Cook damage model for pure commercial copper sheet. For this, three different tensile testing specimens (a smooth (standard) specimen and two notched specimen with different notch radii of 10 and 2 mm) were separated along with the rolling direction and tensile tests were conducted on them. The stress triaxiality was determined for each of the specimens, by using the Bridgeman equation. Next, regards to the dependency of the fracture strain to the stress triaxiality, the constants of Johnson-Cook damage model was determined. Numerical simulation was used to evaluate the satisfaction of the method used to determine the constants of Johnson-cook damage model. For this, the error in fracture strain was used as the criterion and the value of it was calculated for each of the tensile testing specimens. The average value of error in fracture strain for three tested specimens was obtained as of 9.68 percent that showed the satisfaction of the method used in this research to determine the constants of Johnson-Cook damage model. The results of this study can be used to simulate the manufacturing processes of the studied copper sheet.