Open-source application for determination of proof strength based on the plastic extension method

Abstract

Although the modern era brought forward the need for automatization of standard engineering routines, the process of determining proof stress is still mostly done manually. While norms dictate the testing procedure and relevant values, the data evaluation process is left for the user to define and is mostly not a documented part of the analysis. This paper presents an open-source application approach for evaluating tensile test data with the goal of determining the proof stress. The process itself is based on fitting an optimal line through experimental data points.The application requirements are:• Except for test specimen dimensions, no user input is required.• Usable for all materials where yielding occurs.• Will work on a single measurement set as well as multiple data sets.• Open source—addressing transparency and future development for other material testing methods.• Run with MATLAB and Octave.Until now, no numerical consensus existed on how to find the regions other than the procedure defined in EN ISO 6892-1, 2010, nor any heuristic that followed the norm.It is important to note that the application is made up of ten sections. Only three will be elaborated on in detail as they show the core solution.