An Experimental Methodology to Characterize the Plasticity of Sheet Metals from Uniaxial to Plane Strain Tension

• Published in: Experimental mechanics Vol. 61; no. 9; pp. 1381 - 1404
• Main Authors: Fast-Irvine, C., Abedini, A., Noder, J., Butcher, C.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-11-2021; Springer Nature B.V
• Subjects: Aluminum base alloys; BCC metals; Biomedical Engineering and Bioengineering; Calibration; Characterization and Evaluation of Materials; Control; Dual phase steels; Dynamical Systems; Engineering; Experimental methods; Finite element method; Lasers; Metal forming; Metal sheets; Methodology; Optical Devices; Optics; Photonics; Plane strain; Plastic properties; Research Paper; Solid Mechanics; Strain gauges; Tensile tests; Vibration; Yield criteria; Dual-phase steel; Yield condition; Anisotropic material; Plane strain tension; Optimization; Elastic–plastic material
• ISSN: 0014-4851; 1741-2765
• DOI: 10.1007/s11340-021-00744-3

Background
Although accurate knowledge of material behavior in plane strain tension is important for the modelling of sheet metal forming processes, it is often overlooked in yield function calibration because of experimental characterization challenges. Plane strain notch tensile tests, though experimentally convenient, are subject to stress and strain gradients across the gauge width that complicate the analysis.
Objective
A novel experimental integration methodology was developed to exploit these stress and strain gradients to locally calibrate the arc of an anisotropic yield surface from uniaxial-to-plane strain tension.
Methods
Constraining the anisotropic yield surface at the plane strain point, to be consistent with pressure-independent plasticity, enables the local arc to be governed by a single parameter. The arc shape is largely independent of the choice of yield function and can be optimized using a cutting line approach and full-field optical strain measurements. The accuracy of the method was evaluated using finite-element simulations of isotropic and anisotropic materials with different hardening behaviors.
Results
The methodology was applied to a dual phase DP1180 steel and AA5182-O aluminum alloy in the rolling, transverse, and diagonal directions. Data along each of the three locally calibrated arcs was included in calibrations of Yld2000 and Yld2004 yield surfaces.
Conclusions
The plane strain yield strength and arc shape had significant implications on the calibration of advanced anisotropic yield criteria. The yield exponent of the DP1180 agreed with the common value of six for BCC metals while the AA5182 yield surface approximated a Tresca-shape with local yield exponents in excess of 20.