The shaped charge warhead is a critical means of neutralizing armored and fortified targets. It primarily destroys the target through explosive detonation, which results in the liner being crushed to form a high-speed jet. Traditional copper liners form condensed jets, resulting in deep penetration but producing extremely limited post-target damage. Conversely, reactive materials such as Al/PTFE produce divergent particle jets with strong after-effects but suffer from insufficient penetration capability. Energetic high-entropy alloys(EHEAs) can form a “partially cohesive jet”, which is cohesive at the core to ensure penetration and divergent at the periphery to enhance behind-target damage, thereby offering a novel solution to the trade-off between penetration depth and post-effect damage. However, the jet coherence of EHEAs remains challenging to quantify, and no suitable simulation model currently exists.

An integrated test system for jet morphology and post-effect damage was designed. This system uses pulsed X-ray technology to capture the jet morphology and simultaneously assesses penetration and post-effect damage capabilities through the main and post-effect targets. The study proposes a “jet cohesion factor”, defined as the ratio of the area of the central condensed region in the jet X-ray image to the total area. This factor enables a quantitative description of the jet's cohesive state. Additionally, the post-effect damage is calculated by analyzing the scattering angles formed by the perforation distribution on the target surface. To overcome the limitation that the current SPH method cannot quantitatively control the jet cohesion factor, this study develops a secondary correction algorithm for jet morphology based on the SPH algorithm. By introducing an improved Sigmoid function to regulate jet particles, the algorithm achieves a concentrated jet core and controllable edge divergence, thereby accurately reproducing the partially cohesive jet morphology observed in EHEAs.

The present study focused on two Ti–Zr–V–Nb–Al EHEAs with different mechanical properties (Alloy A and Alloy B). The experimental findings demonstrated that Alloy A, characterized by its reduced plasticity(4.8%), exhibited a lower jet cohesion degree (67.5%) and a larger post-effect scattering angle (31.2°). The post-effect target displayed a damage pattern consisting of a main hole accompanied by numerous small holes. In contrast, Alloy B, which demonstrated higher plasticity (8.4%), exhibited a higher jet cohesion degree (78.6%) and a smaller scattering angle (29.6°). The post-effect damage consisted mainly of a main hole accompanied by several larger holes. By adjusting the algorithm parameters, the simulated jet cohesion factors for Alloys A and B were determined to be 67.9% and 77.8%, respectively. Additionally, the deviations of the simulation scattering angles from the experimental values were found to be less than 10%, the simulation results were highly consistent with the experimental data.

The present study successfully developed an integrated testing methodology and a numerical simulation method for the partially cohesive jets formed by EHEA liners. By incorporating the jet cohesion factor, a quantitative approach is provided for elucidating the jet's cohesive state. Furthermore, the jet's morphology control algorithm effectively addresses the lack of adequate simulation models. The high consistency (over 90% agreement) between experimental and simulation outcomes for critical parameters (cohesion factor, scattering angle) substantiates the efficacy of the proposed methodologies. These findings not only provide critical technical support for the rapid performance evaluation and compositional microstructure optimization of EHEA liners but also offer a novel scientific approach for assessing the multifunctional damage efficiency of shaped charge warheads.

Energetic structural materials (ESMs) have provided a novel pathway for substantially enhancing the power of weapons. Their damage effects are significantly dependent on their dynamic mechanical properties and impact-induced energy release characteristics. However, current research has not yet established an integrated testing methodology that correlates these two aspects, leading to a lack of effective guidance for designing ESMs and optimizing warhead charge structures.

An impact-induced energy release characteristics testing system was established by integrating a split Hopkinson pressure bar (SHPB) apparatus. The system primarily comprised an SHPB impact loading system and an energy release characteristic testing system. The SHPB impact loading system was utilized to test the dynamic mechanical properties and to provide the impact load necessary to induce the energy release of ESMs. The energy release characteristic testing system, installed in conjunction with the SHPB impact loading system, mainly consisted of an energy release testing vessel, a pressure acquisition module, and a temperature acquisition module. A sample was clamped between the incident and transmitted bars of the SHPB, which were then placed inside the energy release testing vessel. Considering that the energy release reaction of ESMs in their actual service environment is primarily oxidation, the energy release calculation model was modified to account for oxygen consumption. The SHPB impact loading system and the energy release characteristic testing system were triggered by a stress pulse signal, thereby enabling the concurrent measurement of dynamic mechanical properties and energy release characteristics. The materials tested in this study were Ti–Zr–Hf–Ta-based energetic high-entropy alloys with solution treatment (ST) and aging treatment (AT), which represented typical ESMs.

The dynamic compressive yield strengths of the ST and AT alloys were 1657 and 1 816 MPa, respectively, with corresponding failure strains of 0.47 and 0.35. Upon instantaneous impact loading by the SHPB, the samples underwent deformation and fragmentation and released energy, leading to a rapid increase in the overpressure within the testing vessel. The measured peak overpressures for the ST and AT alloys were 9.19 and 268.63 kPa, respectively. According to the modified energy release calculation model, the energy releases per unit mass were 16.28 and 475.77 J/g, respectively. After recovering the samples from the testing vessel, the AT alloy exhibited more extensive fragmentation, consistent with its lower failure strain. Energy release images also showed that the sparks from the AT alloy rapidly filled the testing vessel, whereas the sparks from the ST alloy were concentrated near the sensors, further demonstrating that the energy release of the AT alloy was more intense than that of the ST alloy. This observation was consistent with the mechanical properties, degree of fragmentation, and energy release of the materials, thereby validating the effectiveness and reliability of the impact-induced energy release testing system and achieving the design goals.

The proposed system can acquire key energy release parameters, such as the energy release and the threshold for impact-induced energy release, as well as mechanical property parameters, including dynamic compressive strength and failure strain. This achievement allows for a quantitative correlation between the mechanical properties and energy release characteristics of ESMs, thereby providing experimental technical support for the development of novel ESMs. The system is characterized by its flexible assembly, ease of operation, precision, and efficiency, allowing for rapid assessment of the impact-induced energy release characteristics of ESMs under laboratory conditions.