Effectiveness of thermoviscoplastic material models in predicting the thermomechanical behavior of rolled homogenous armor steel

• Published in: Physica scripta 2024-08, Vol.99 (8), p.859
• Main Authors: Gangwar, Vaibhav, Bhattacharjee, Snehasish, Acharyya, Sanjib Kumar, Dhar, Sankar, Banerjee, Arkadeb, Chakraborty, Santu
• Format: Article
• Language: English
• Subjects: ABAQUS; armor material; damage; material model; rate-dependent behavior
• ISSN: 0031-8949; 1402-4896
• DOI: 10.1088/1402-4896/ad6493

This paper studies the dynamic and elevated temperature behavior of rolled homogeneous armor steel, which is crucial for applications such as blast, impact, crash, and ballistic resistance. The deformation behavior is analyzed through tensile tests. The tensile tests of RHA steel are conducted at quasi-static 10 − 4 s − 1 ≤ ε p ̇ ≤ 10 − 1 s − 1 to dynamic 10 − 1 s − 1 ≤ ε p ̇ ≤ 36.439 s − 1 strain-rates and at high temperatures ranging from room temperature ( RT , 27 ° C ) to 5 00 ° C . Phenomenological Johnson-Cook (JC) models and semi-physical Rusinek-Klepaczko (RK) material models are employed in finite element (FE) simulations of tensile tests. The JC failure model, with a small modification, is used along with the material models to simulate the loss of load-bearing capacity of the component. All necessary material parameters are extracted from the test data. The material models and the damage model are integrated into ABAQUS CAE FE software through a user-defined material subroutine (UMAT). The simulated outcomes acquired from diverse material models are validated with relevant experimental findings, and the effectiveness of each material model is evaluated through qualitative and quantitative assessments. Observations reveal limitations in the existing models to accurately replicate material behavior under tension, particularly in the dynamic strain rate, and elevated temperature range. Consequently, a modified version of the JC model (MJC) is explored to better account for the impact of temperature on strain hardening and strain rate hardening. The proposed modification in the material model significantly enhances the predictive accuracy of FE simulations of tensile deformation across the entire spectrum of studied strain rates and temperatures compared to the original JC and RK models.