Extension of the sensitivity-based virtual fields to large deformation anisotropic plasticity

Abstract

The virtual fields method is an approach to inversely identify material parameters using full-field deformation data. In this work, we extend the sensitivity-based virtual fields to large deformation anisotropic plasticity. The method is firstly generalized to the finite deformation framework and then tested on numerical data obtained from a finite element model of a deep-notched specimen subjected to a tensile loading. We demonstrated the feasibility of the method for two anisotropic plasticity models: Hill48 and Yld2000-2D, and showed that all the parameters could be characterise from such a test. The sensitivity-based virtual fields performed better than the currently accepted standard approach of user-defined ones in terms of accuracy and robustness. The main advantage of the sensitivity-based virtual fields comes from the automation of virtual fields generation. The process can be applied to any geometry and any constitutive law. Keywords The virtual fields method • Anisotropic plasticity • Sensitivity-based virtual fields • Material testing • Full-field measurements

Single‐camera special stereo‐digital image correlation applied for accurate virtual fields method identification

“…The optimised definition of virtual fields for an elastoplastic problem is still an unresolved issue. Special virtual fields and sensitivity‐based virtual fields can be automatically generated to minimise the impact of the noised strain fields and was also applied in plastic parameters identification but only yield a relative success . Select suitable virtual fields are significant in the VFM identification employing noised test data.…”

Experimental Validation of the Sensitivity-Based Virtual Fields for Identification of Anisotropic Plasticity Models

“…It can be estimated from the constitutive law (e.g. assuming plane stress elasticity and isochoric plastic flow) [47], or can be directly measured by means of back-to-back camera systems as shown in [54]. The virtual displacements (and their spatial derivatives, later simply referred to as virtual fields) spatially probe the reconstructed stress field for information.…”

“…This is particularly important for less influential parameters which may only affect the deformation fields over certain time steps and specific areas of the specimen. Recently, a new type of virtual field has been proposed to address the limitations described above, namely the sensitivity-based virtual fields (SBVFs) [46,47]. These fields are automatically generated for any constitutive model, and any test geometry based on the sensitivity of the reconstructed stress field to each material parameter.…”

Identification of Constitutive Parameters Governing the Hyperelastic Response of Rubber by Using Full-Field Measurement and the Virtual Fields Method

“…The virtual displacement fields are then generated proportionally to the stress sensitivity fields through a finite element-like approach. The method was then extended to finite strain for anisotropic plasticity in [11]. For finite strains, the stress sensitivity field is defined by…”