Identification of 7B04 aluminum alloy anisotropy yield criteria with conventional test and Pottier test at elevated temperature

International audience7B04 aluminum alloy is widely used for strength critical aerospace structural applications. In this paper, the plastic anisotropy of this alloy at 200 °C was investigated based on Hill'48 and Yld2000-2D yield criteria. Thermal tensile test at setting temperature was carried out by a designed electrical heating system and the strain field was measured by the digital image correlation system simultaneously. Parameters of Hill'48 yield criterion with Voce hardening were determined directly based on the thermal tensile test. The parameters of Yld2000-2D criterion were obtained by the inverse identification method with Pottier test at elevated temperature which can generate heterogeneous strain fields. Deep drawing test was carried out at 200 °C and the earing heights were measured. The accuracy of the determined yield criteria parameters was validated by numerical and experimental deep drawing test results. © 2019 The Author

An evolutionary anisotropic model for sheet metals based on non-associated flow rule approach

We present a phenomenological approach to describe the evolution of anisotropy during plastic deformation. In the presented model, anisotropy evolution is described in terms of both distortional hardening and variation of Lankford coefficients. A non-associated flow rule (non-AFR) based Yld2000-2d anisotropic yield model is employed in which separate yield function and plastic potential are considered which attributes excellent accuracy and flexibility to the model. However, as is the case for the majority of phenomenological anisotropic models, the non-AFR Yld2000-2d model preserves the initial anisotropy during the entire plastic deformation. To include evolutionary characteristics in the model, the shape of plastic potential and yield function should be sensitive to plastic deformation. Therefore, we use polynomial functions to describe the pattern present in the evolution of plastic potential and yield functions. The proposed model was evaluated based on experimental results of interstitial free DC06 deep drawing steel. Despite its simplicity, the proposed evolutionary non-AFR Yld2000-2d model shows excellent accuracy in predicting the evolution of Lankford coefficients and yield stresses during plastic deformation. (C) 2013 Elsevier B.V. All rights reserved.X112322sciescopu