A software for research and education in ductile damage

Abstract

This paper gives insight into the development and utilization of a computer software that uses raw experimental data from the load cells and DIC systems to obtain the instant of time at fracture $t_f$, the loading paths in principal strain space ${\epsilon }_1=f\left({\epsilon }_2\right)$, and their conversion into the space of effective strain vs. stress triaxiality $\bar{\epsilon }=f\left(\eta \right)$. Special emphasis is given to the different assumptions and stress triaxiality measures that can be used to convert the loading paths from principal strain space into the space of effective strain vs. stress triaxiality. Results for double-action radial extrusion show the differences of treating the loading paths as linear or non-linear from beginning until the onset of failure by fracture. Results also allow concluding on the importance of accounting for the stress triaxiality derived from individual experimental measurements in an average sense over the entire loading paths, to avoid overestimation and mislocation of the fracture forming limits. The applicability of the software for education and training of students in formability is also discussed.