Validation of Complex Material Models using Hole-Expansion Experiments
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Date
2024-03
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Abstract
The ability to accurately predict and evaluate the mechanical behavior of materials is of paramount importance in engineering and scientific research. Complex material models that include anisotropic behavior (where material properties are directionally dependent) are becoming more prevalent due to advancements in high-performance computing and the need to accurately predict the behavior of a wide range of materials and structures in extreme environments. While these complex models often outperform simpler isotropic models, they require significantly more experimental effort to calibrate and validate. Once a material model has been calibrated, validation is required to ensure that the model performs as expected so that it can be implemented into numerical models to predict the performance of materials and structures in extreme environments. In this work, novel full-field hole expansion experiments (on 6061-T6 aluminum sheet) with a flat punch are used as a unique way to validate anisotropic plasticity models because all stress states identified during model calibration are experienced in a single multi-axial experiment. In these experiments, a pre-existing hole in the sheet is expanded by a flat punch contacting the surface. Full-field measurements of the expanding sheet are made using digital image correlation, where a random speckle pattern is applied to the bottom surface of the sheet and tracked using stereo cameras synced to the testing frame. Experimental results from the hole-expansion test are compared to numerical simulations of the experiment implementing the anisotropic material model. In addition, the traditional experimental approach to calibration of an anisotropic plasticity model on the aluminum sheet material is performed utilizing uniaxial tension tests at 15° increments. Overall, a good correlation is seen between experiments and simulations of the hole-expansion test.
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Engineering: 3rd Place (The Ohio State University Edward F. Hayes Advanced Research
Forum)
Keywords
Anisotropy, Material Behavior, Experimental Testing, Numerical Simulations