Title: A study on the influence of different variables for determination of flow stress using hydraulic bulge test

Authors: Bruno Martins; Abel D. Santos; Pedro Teixeira

Addresses: INEGI – Institute of Mechanical Engineering and Industrial Management, University of Porto, Rua Dr. Roberto Frias 400, 4200-465 Porto, Portugal ' INEGI – Institute of Mechanical Engineering and Industrial Management, University of Porto, Rua Dr. Roberto Frias 400 4200-465 Porto, Portugal; FEUP-DEMec – Department of Mechanical Engineering, Faculty of Engineering, University of Porto Rua Dr. Roberto Frias s/n 4200-465 Porto, Portugal ' INEGI – Institute of Mechanical Engineering and Industrial Management, University of Porto, Rua Dr. Roberto Frias 400, 4200-465 Porto, Portugal

Abstract: Mechanical characterisation usually involves the standard uniaxial tensile test, providing relevant properties of sheet metal materials, which are used in numerical modelling of sheet forming operations to predict and assess formability and failure analysis. Since the range of strain obtained from tensile test is limited, extrapolation using a defined hardening law will be needed, thus being possible having dissimilar data for higher strains. The use of bulge test allows higher ranges of deformation and therefore, lower extrapolation. This paper presents a study on numerical modelling of the biaxial expansion bulge test and performs a sensitivity analysis on variables used to calculate the stress and strain, which strongly affects the accuracy of the obtained hardening curve. This analysis is done for some influencing variables used in measurements, thus specifying some directions in the design and use of a developed experimental mechanical system, in order to obtain better accuracy for such results.

Keywords: hydraulic bulge test; flow curve; material characterisation; sheet metal forming; FEM; finite element method; variables; flow stress; hardening law; deformation; numerical modelling; strain.

DOI: 10.1504/IJMATEI.2013.054392

International Journal of Materials Engineering Innovation, 2013 Vol.4 No.2, pp.132 - 148

Published online: 06 Jun 2013 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article