Determination of the Actual Stress–Strain Diagram for Undermatching Welded Joint Using DIC and FEM

• Published in: Materials Vol. 14; no. 16; p. 4691
• Main Authors: Milošević, Nenad Zoran, Sedmak, Aleksandar Stojan, Bakić, Gordana Miodrag, Lazić, Vukić, Milošević, Miloš, Mladenović, Goran, Maslarević, Aleksandar
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 20-08-2021; MDPI
• Subjects: actual stress–strain diagram; DIC; Digital imaging; Engineering; FEM; Finite element method; Geometry; Grooves; Martensitic stainless steels; martensitic steel; Mathematical analysis; Mechanical properties; Methodology; Research methodology; Steel; Strain analysis; Stress concentration; Stress-strain curves; Stress-strain relationships; True stress; undermatching weld; Welded joints; Yield stress
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14164691

This paper presents new methodology for determining the actual stress–strain diagram based on analytical equations, in combination with numerical and experimental data. The first step was to use the 3D digital image correlation (DIC) to estimate true stress–strain diagram by replacing common analytical expression for contraction with measured values. Next step was to estimate the stress concentration by using a new methodology, based on recently introduced analytical expressions and numerical verification by the finite element method (FEM), to obtain actual stress–strain diagrams, as named in this paper. The essence of new methodology is to introduce stress concentration factor into the procedure of actual stress evaluation. New methodology is then applied to determine actual stress–strain diagrams for two undermatched welded joints with different rectangular cross-section and groove shapes, made of martensitic steels X10 CrMoVNb 9-1 and Armox 500T. Results indicated that new methodology is a general one, since it is not dependent on welded joint material and geometry.