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Reactive materials (RMs) are special type of impact-initiated energetic materials that have been widely studied with broad military application prospects. However, simulating the ignition and reaction of RMs using current numerical methods is difficult due to their complex mechanism related to high dynamic loads. In this work, based on a theoretical model consisting of impact ignition criteria and chemical reaction rate of polymer-based RMs, a numerical method with a unified equation of state was proposed and compiled as an executable program. Experiments consisting of typical polytetrafluoroethylene /Al RM projectiles impacting double-spaced plates were conducted and simulated using the user-compiled program, and the results verified the effectiveness of the numerical method. The simulation also qualitatively analyzed the second-collision induced reaction enhancement mechanism. In addition, the results revealed that the kinetic-chemical combined effect is a crucial factor that determined the damage enhancement effect on the rear plates. [ABSTRACT FROM AUTHOR]

Polytetrafluoroethylene/aluminum (PTFE/Al) reactive material is a pivotal research object in the aerospace, military, and mechanical engineering fields and can release chemical energy (CE) under shock or impact. However, its relatively low mechanical strength limits its applications. The present paper proposes a Cu-PTFE/Al (73.5wt. %/26.5wt. %) double-layer liner that can form tandem explosive formed projectiles (EFPs) under the shock of shaped charges, which not only retains the strong penetration ability but also shows a more significant lateral enhancement effect through the deflagration reaction. Here, the preparation process of the PTFE/Al liner is given, and an analytical model for the Cu-PTFE/Al tandem EFP of the damage process against multi-spaced plates is established, revealing the penetration and deflagration-enhanced mechanisms. Subsequently, a two-step segmented numerical simulation for the penetration–deflagration coupling effects is conducted, and the time-space interaction process and damage results between kinetic energy penetration and CE deflagration are obtained. A series of experiments of tandem EFPs against spaced plates are conducted, including the different materials, thickness ratio, and standoff. Experimental results show that compared with Cu–Cu tandem EFP with the same condition, the penetration ability of Cu-PTFE/Al composite EFP is reduced, but the damage enhancement effect is greatly improved; the maximum damage area of a single plate is increased by 220.1%, and the average damage area of a single plate is increased by 76.2%. This study provides important reference data and a theoretical basis for the design of metal-reactive tandem EFPs. [ABSTRACT FROM AUTHOR]

Aiming at describing the mechanics–thermotics–chemistry coupling response of the reactive material liner under impact loading, the Grüneisen equation of state in the form of P–V–T was derived. Combined with the impact temperature rise theory, heat conduction theory, and Arrhenius chemical reaction kinetic model, the mechanics–thermotics–chemistry coupling response model is established. A numerical simulation framework for the thermodynamic response of reactive materials under impact load was established, and numerical simulation codes for the impact-induced energy release behavior of reactive materials was developed based on the material point method, which realized the numerical simulation of the formation behavior of the reactive material penetrator (jet) under explosion load. The results show that chemical reactions occur in the process of reactive material jet formation, and high temperature and high pressure products make the jet expand and thicken constantly, resulting in the decrease in the density of the jet head and the increase in the cross-sectional area. As such, the jet has hardly any armor-piercing capability at stand-offs of 2.5 times the caliber, and the simulation results are in good agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Reactive material fragment is an extremely efficient damage enhancement technology that incorporates the defeat mechanisms of kinetic energy and chemical energy. In this paper, the polymer-based reactive material fragment/target interactions are investigated. Related dynamic testing techniques for energy release characteristics of reactive material fragments are presented, and a series of ballistic experiments is conducted. The results show the reactive material fragment, which perforates the closed test chamber, undergoes a violent chemical reaction under highly dynamic loads and releases great amounts of thermo-chemical energy on the interior. The impact-initiated process and energy release behavior are markedly influenced by the impact velocity, indicating the material's fracture is of importance to the reaction. A relationship between the maximum pressure inside the chamber and the reaction efficiency is derived to analyze the influence quantitatively, and the venting effects are also considered. [ABSTRACT FROM AUTHOR]