PSI - Issue 72

Kevin Fabian Arsaputera et al. / Procedia Structural Integrity 72 (2025) 409–417

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1. Introduction Developing protective structures against ballistic threats is increasingly vital across engineering applications [Yu et al. (2025), Merwe et al. (2024), Elwi et al. (2023), Chang et al. (2024)]. Advancements in technology drive the need for efficient materials, emphasizing the importance of understanding material behavior under high-velocity impacts. This study examines the ballistic impact response of Aluminum 1100-H12 plates, known for their mechanical properties and energy absorption capabilities. Ballistic impacts involve complex interactions, including plastic deformation, strain rate effects, and thermal softening, which influence penetration resistance and energy absorption. Gupta et al. (2007) explored the effects of projectile nose shape and impact velocity on aluminum plates, providing critical insights into penetration mechanics. The Johnson-Cook constitutive model has been widely adopted to describe material behavior under high-strain rate conditions, Johnson et al. (1983). This model incorporates the effects of plastic strain, strain rate, and tem-perature on material flow stress, expressed as: =( + · ₚⁿ)(1+ · ( ̇ₚ))(1 − ( ₘ ₑₗ−ₜ − ᵣ ₒ ₒᵣₒₘₒₘ ) ) (1) In this constitutive equation, σ represents the flow stress of the material, where εₚ denotes the equivalent plastic strain and ε̇ₚ is the plastic st rain rate. The temperature effects are accounted for through T, representing the current material temperature, while T ᵣₒₒₘ and Tₘₑₗₜ correspond to room and melting temperatures, respectively. The material specific constants A, B, n, C, and m are determined through experimental testing and characterize the material's response to various loading conditions. Recent research by Rahman et al. (2024) has demonstrated the significance of attack angle and target location in bullet-structure interactions, particularly in sandwich panel configurations. In ballistic impact analysis, the energy absorption capacity (Ea) of the target plate is a critical parameter, calculated as: = ½ ( ᵢ 2 − ᵣ 2 ) (2) The energy absorption equation relates the projectile mass m with its initial velocity v ᵢ and residual velocity v ᵣ after impact, providing a quantitative measure of the target's energy absorption capability during the impact event. Additionally, the ratio of target thickness to projectile diameter (T/D) is expressed as: T/D = t/d (3) This dimensional ratio, where t represents the target thickness and d denotes the projectile diameter, is crucial in characterizing the geometric relationship between the target and the projectile. This study combines experimental ballistic tests and finite element simulations using ABAQUS software Do et al. (2024). Experimental tests involve varying impact velocities and projectile geometries, while numerical simulations validate theoretical predictions and analyze dynamic responses. The research objectives are to evaluate the ballistic performance of Aluminum 1100-H12 plates under diverse impact conditions and validate numerical simulations with experimental data. These findings aim to enhance understanding of material behavior under high-velocity impacts and contribute to developing advanced protective structures. 2. Literature Review The evolution of ballistic protection materials has been marked by significant advancements in both experimental techniques and numerical modeling approaches. Alwan et al. (2022) conducted comprehensive studies on aluminum alloys under high-velocity impact conditions, establishing fundamental relationships between material properties and ballistic performance. Their work demonstrated that the mechanical response of aluminum plates is highly dependent on impact velocity regimes and local deformation mechanisms. Building upon this foundation, recent investigations by Tiwari et al. (2020) have revealed that the strain-rate sensitivity of Aluminum 1100-H12 plays a crucial role in its energy absorption capabilities during ballistic events.