A novel approach to determine plastic hardening curves of AA7075 sheet utilizing hydraulic bulging test at elevated temperature

Liu, Kangning; Li, Lihui; Cai, Gaoshen; Yang, Xinqi; Guo, Cheng; Liu, Baosheng

doi:10.1016/j.ijmecsci.2015.07.002

Cited by 27 publications

(11 citation statements)

References 33 publications

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“…The out-of-plane test at room temperature has been standardised. It has been used to obtain FLDs at elevated temperature as well [18]. Ayres et al [19] investigated the effects of temperature and strain rate on the formability of AA5182 at a temperature of 130°C and 200°C.…”

Section: Introductionmentioning

confidence: 99%

Formability evaluation for sheet metals under hot stamping conditions by a novel biaxial testing system and a new materials model

Shao

Lin

et al. 2017

International Journal of Mechanical Sciences

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Published: Z. Shao, N. Li, J. Lin, T. Dean, 2017, Formability evaluation for sheet metals under hot stamping conditions by a novel biaxial testing system and a new materials model, Int. J. Mech. Sci., 120, pp149-158. AbstractHot stamping and cold die quenching has been developed in forming complex shaped structural components of metals. The aim of this study is the first attempt to develop unified viscoplastic damage constitutive equations to describe the thermo-mechanical response of the metal and to predict the formability of the metal for hot stamping applications. Effects of parameters in the damage evolution equation on the predicted forming limit curves were investigated. Test facilities and methods need to be established to obtain experimental formability data of metals in order to determine and verify constitutive equations. However, conventional experimental approaches used to determine forming limit diagrams (FLDs) of sheet metals under different linear strain paths are not applicable to hot stamping conditions due to the requirements of rapid heating and cooling processes prior to forming. A novel planar biaxial testing system was proposed before and was improved and used in this work for formability tests of aluminium alloy 6082 at various temperatures, strain rates and strain paths after heating, soaking and rapid cooling processes. The key dimensions and features of cruciform specimens adopted for the determination of forming limit under various strain paths were developed, optimised and verified based on the previous designs and the determined heating and cooling method [1]. The digital image correlation (DIC) system was adopted to record strain fields of a specimen throughout the deformation history. Material constants in constitutive equations were determined from the formability test results of AA6082 for the prediction of forming limit of alloys under hot stamping conditions. This research, for the first time, enabled forming limit data of an alloy to be generated at various temperatures, strain rates and strain paths and forming limits to be predicted under hot stamping conditions.

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Section: Introductionmentioning

confidence: 99%

Formability evaluation for sheet metals under hot stamping conditions by a novel biaxial testing system and a new materials model

Shao

Lin

et al. 2017

International Journal of Mechanical Sciences

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“…The theory was later modified by Panknin, 22 who further incorporated the effect of the die fillet radius on the curvature at the apex. Panknin’s model was recently adopted by Liu et al 3 and Janbakhsh et al 2…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, the hydraulic bulge test allows much more significant sheet metal deformation before strain localization or ductile failure. [1][2][3] Therefore, it serves as an efficient alternative to extract the hardening response of sheet metal for large strains. [4][5][6] In addition, it is also useful for the evaluation and identification of the yield functions 7,8 and ductile failure criteria 9,10 for metal materials.…”

Section: Introductionmentioning

confidence: 99%

On the identification of material hardening for anisotropic sheets via bulge tests

Luo

Chen

Yuan

2022

Proceedings of the Institution of Mechanical Engineers, Part C:

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The hydraulic bulge test provides a useful tool to characterize the mechanical behavior of sheet metal under nearly equibiaxial loading, such as the material hardening response. However, the kinematic relationships during bulge tests of anisotropic sheets are still less understood and need further clarification. To this end, extensive numerical simulations of bulge tests are first performed, covering different die geometries and materials that exhibit distinct hardening features and Hill48 anisotropy. Based on the general scaling laws of the kinematic relationships, the numerical results are then used to establish an analytical model that explicitly relates the dome height, apex strain, and radii of curvatures in terms of the die ratio, material hardening parameter, and anisotropy. In addition, the general extraction procedure, which incorporates the analytical model to obtain the hardening responses of anisotropic sheets, is also provided. Finally, the effectiveness of the analytical model is confirmed based on representative results of AA6061 and DP600 sheet experiments and supplementary numerical simulations. The proposed model is expected to help facilitate the application of bulge tests in characterizing the plasticity and forming behavior of anisotropic sheet materials.

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“…Warm/hot sheet hydroforming was proposed to enhance the plasticity of lightweight materials [1][2][3][4]. This innovative and flexible processing method combines the advantages of cold sheet hydroforming and warm/hot sheet forming [5][6][7] and is regarded as an advanced technique for improving material formability [8][9][10][11]. In contrast to the conventional sheet hot stamping process, fluid pressure provides the through-thickness normal stress and assists the sheet formation process during warm/hot sheet hydroforming [12,13].…”

Section: Introductionmentioning

confidence: 99%

A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test

Cai

Zhang

et al. 2020

Materials

Self Cite

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In order to predict the wrinkling of sheet metal under the influence of fluid pressure and temperature during warm/hot hydroforming, a numerical simulation model for sheet wrinkling prediction was established, taking into account through-thickness normal stress induced by fluid pressure. From simulations using linear and quadratic elements, respectively, it was found that the latter gave results that were much closer to experimental data. A novel experimental method based on an improved Yoshida Buckling Test (YBT) was proposed for testing the wrinkling properties of sheets under the through-thickness normal stress. A wrinkling coefficient suitable for predicting wrinkling was also presented. Based on the numerical simulations, an experimental validation of wrinkling performance was conducted. Ridge-height curves measured along the main diagonal tensile direction of the sheet were presented and showed that the wrinkling prediction criterion provided good discrimination. Furthermore, the wrinkling properties of several different materials were simulated to evaluate the accuracy of the prediction method, and the results revealed that the improved YBT gave good predictions for wrinkling in the conventional sheet metal forming process, while the prediction results for wrinkling in warm/hot sheet hydroforming were also accurate with the fluid pressure of zero.

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A novel approach to determine plastic hardening curves of AA7075 sheet utilizing hydraulic bulging test at elevated temperature

Cited by 27 publications

References 33 publications

Formability evaluation for sheet metals under hot stamping conditions by a novel biaxial testing system and a new materials model

Formability evaluation for sheet metals under hot stamping conditions by a novel biaxial testing system and a new materials model

On the identification of material hardening for anisotropic sheets via bulge tests

A Novel Approach to Predict Wrinkling of Aluminum Alloy During Warm/Hot Sheet Hydroforming Based on an Improved Yoshida Buckling Test

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