Comparison of Different Biaxial Tests for the Inverse Identification of Sheet Steel Material Parameters

Abstract

The aim of this work is to compare different biaxial specimen geometries and loading conditions concerning their applicability as experimental database for an inverse finite element model updating procedure to identify the material parameters of sheet steel. Therefore, the deformation of the specimens is recorded with an optical, three‐dimensional full‐field deformation measurement system, and the utilised displacement data at the surface of the specimens are calculated via digital image correlation. The numerical material model for the simulations is based on a three‐dimensional, anisotropic elasto‐plastic ansatz and is implemented into a commercial finite element software code. The material parameters that are identified with the different specimen geometries are the hardening variables and the anisotropic plastic values. Based on the identification results, a selection criterion for the evaluation of specimen geometries for the inverse parameter identification is presented.

A non-invasive node-based form finding approach with discretization-independent target configuration

“…This is approximated by 480 fournoded, isoparametric, quadrilateral elements with a four-point Gaussian integration. The material data of the deep drawing steel DC04 published in [13] is used. The high hardening capacity and low initial yield strength of the DC04 are typical for cold rolled sheet metal and are working well for large deformations.…”

Identification of material parameters for thin sheets from single biaxial tensile test using a sequential inverse identification strategy

“…Generally, this assessment is performed using the following procedures. One of them consists on the comparison between experimental and identified results from simple classical tests (e.g., [31,33,34]), which are not representative of the whole plastic behaviour, even if in a large number. Also, the direct comparison between the assessed results with those obtained with other identification strategies is used (e.g., [29,32,35,36]).…”

“…A comprehensive overview on this topic can be found in [27]. Approaches for the inverse parameters identification have been conducted using the biaxial tensile testing of cruciform specimens (see e.g., [28][29][30][31][32]). For example, in a recent work by Zhang et al [32], the parameters identification of Hill'48 [1] and Bron and Besson [5] yield criteria was performed for AA5086 aluminium sheet, using two methods: (i) a classical one, using conventional homogeneous tests, and (ii) an inverse analysis, from only one biaxial tensile test of a cruciform sample.…”

On gradient‐based optimization strategies for inverse problems in metal forming

“…A couple of strategies exist to tackle this task, see Avril et al [13] for an overview. The approach we follow in this contribution is the Finite Element Model Updating (FEMU) strategy with respect to a minimization of the displacement differences, see [14].…”

“…For the identification process itself a cruciform specimen with a hole according to [14] is loaded in equi-biaxial tension and the deformation is captured with the full-field optical measurement system ARAMIS. For the FE model the specimen geometry is meshed with 3832 linear hexahedral elements as shown in Fig.…”