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The modeling clay is an oil-based soft, flowable, and pliable material made from waxes and oils. Besides its primary use for making sculptures, the modeling clay is commonly used to evaluate bulletproof vests and simulate metal manufacturing processes by conformation. In ballistic tests, the clay is used to retain the deformation of the rear face of body armors; and in the study of metal forming processes, it is used as a physical model to provide information on the plastic flow. However, its mechanical dynamic behavior is not entirely understood. In this study, Plastilina Roma No. 1 modeling clay was mechanically characterized using the power-law constitutive model at medium strain rates (10 2 s − 1). The material parameters were determined using a penetration model based on the Cavity Expansion Theory and an inverse technique involving the comparison of the model with experimentation. The optimum set of constitutive parameters was found by reducing the difference of the calculated penetration profile and the measurements from a drop test. This optimization process was programmed on the MATLAB–Simulink environment. The determined material parameters were validated by comparing the results from a computational model with three test set-ups. Finite element model results show good concordance with experimental measurements. [ABSTRACT FROM AUTHOR]

Internal void defects as shrinkage porosity, gas bubble, and thermo‐mechanical cracks are usually formed during steel casting processes. These defects have critical impact on the quality and service life of hot‐rolled products. Study of the possibility of self‐healing of existing internal defects during hot‐rolling process has been of interest to industry and researchers. Prediction of void closure is extremely useful in relation to better product design and manufacturing process optimization. Herein, a 3D finite element model of the slab hot‐rolling process is developed to simulate and analyze the healing of internal voids in hot‐rolled steel plate. The material model for the steel plate is developed based on Johnson–Cook constitutive relation to accurately represent its viscoplastic behavior at high temperatures as well as account for strain rate sensitivity. The study evaluates the thermal and mechanical response of low‐carbon steel slabs having pre‐existing voids during multi‐pass strands reverse hot‐rolling process. Through thickness plastic strains within the slab are found to influence void closure. Results show that variation in void size and locations also affect the healing possibilities. Finally, the effect of thermal history and thermo‐mechanical stresses on void closure is studied. [ABSTRACT FROM AUTHOR]