Material Model Validation for Flexible Targets
Bird Strike Crashworthiness
K.J. Zandbergen (TU Delft - Aerospace Engineering)
S. Giovani Pereira Castro – Mentor (TU Delft - Group Giovani Pereira Castro)
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Abstract
This thesis presents a methodology for constitutive material modeling of flexible targets, with a specific emphasis on finite element analysis. The Johnson-Cook constitutive model is employed in combination with a customized Bao-Wierzbicki damage model, both implemented in Abaqus/Explicit through a user-defined material subroutine (VUMAT). The primary objective is to evaluate the accuracy of the finite element simulations by comparing them to experimental tensile test data. To this end, the dogbone specimen used in an experimental test was reconstructed in Abaqus, and stress-strain as well as reaction force-strain data were extracted from a single finite element located in the necking region. These data were then compared to strain measurements obtained via Digital Image Correlation (DIC) from the physical experiments. The analysis was performed across four mesh densities to assess mesh convergence.
The results indicate a reasonable agreement between the simulated and experimental force-strain and stress-strain responses. Minor discrepancies were observed, largely attributable to uncertainties in the experimental measurements. Overall, the simulations demonstrate the ability of the implemented material and damage models to capture key aspects of the observed mechanical behavior.
This validated simulation framework provides a foundation for future investigations involving high-deformation phenomena. It is particularly relevant for impact analyses, such as bird strike scenarios in aerospace applications.