Defence Technology(防务技术)最新文献

{"title":"Modification and experimental validation of the Forrestal-Warren perforation model for high hardness armor steel plates of intermediate thickness","authors":"Radovan Djurovic,&nbsp;Predrag Elek,&nbsp;Milos Markovic,&nbsp;Dejan Jevtic","doi":"10.1016/j.dt.2024.11.006","DOIUrl":"10.1016/j.dt.2024.11.006","url":null,"abstract":"<div><div>This paper proposes a modification of the Forrestal-Warren perforation model aimed at extending its applicability range to intermediately-thick high-hardness armor steel plates. When impacted by armor-piercing projectiles, these plates tend to fail through adiabatic shear plugging which significantly reduces their ballistic resistance. To address this effect, an approach for determining effective thickness was defined and incorporated into the predictive model. Ballistic impact tests were performed to assess the modification's validity, in which ARMOX 500T steel plates were subjected to perpendicular impacts from 7.62 × 39 mm steel-cored rounds under various velocities. Frequent target failure by soft plugging was observed, as well as the brittle shatter of the hard steel core. Key properties of the recovered plugs including their mass, length and diameter were measured and reported along with the projectiles' residual velocities. Additionally, independent data from the open literature were included in the analysis for further validation. The original Forrestal-Warren model and the novel effective thickness modification were then used to establish the relationship between impact and residual velocities, as well as to determine the ballistic limit velocity. The comparison revealed that the proposed approach significantly improves the model's accuracy, showing a strong correlation with experimental data and reducing deviations to within a few percent. This enhancement highlights the potential of the effective thickness term, which could also be applied to other predictive models to extend their applicability range. Further exploration into other armor steels and impact conditions is recommended to assess the method's versatility.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 267-284"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the effects of combustion characteristics of pyrotechnic charges on pyrotechnic shocks","authors":"Jingcheng Wang ,&nbsp;Shihui Xiong ,&nbsp;Huina Mu ,&nbsp;Xiaogang Li ,&nbsp;Yuquan Wen","doi":"10.1016/j.dt.2024.12.015","DOIUrl":"10.1016/j.dt.2024.12.015","url":null,"abstract":"<div><div>This study calculates the combustion characteristics of various gas-generating and micro gas pyrotechnic charges, including aluminium/potassium perchlorate, boron/potassium nitrate, carbon black/potassium nitrate, and silicon-based delay compositions, using thermodynamic software. A multiphase flow-thermal-solid coupling model was established, and the combustion process of the pyrotechnic charges within a closed bomb was simulated. The pyrotechnic shock generated by combustion was predicted. The combustion pressures and pyrotechnic shocks were measured. The simulation results demonstrated good agreement with experimental results. Additionally, the mechanism of shock generation by the combustion of pyrotechnic charges in the closed bomb was analyzed. The effects of the combustion characteristics of the pyrotechnic charges on the resulting pyrotechnic shocks were systematically investigated. Notably, the shock response spectrum of the gas-generating pyrotechnic charges is greater than that of the micro gas compositions at most frequencies, particularly in the mid-field pyrotechnic shocks (3–10 kHz). Furthermore, the pyrotechnic shocks increase approximately linearly with the impulse of the gas-generating pyrotechnic charges.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 79-98"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of cryogenic treatment on mechanical and ballistic properties of AA5754 alloy friction stir welded joints","authors":"V. Manoj Mohan Prasath ,&nbsp;S. Dharani Kumar ,&nbsp;Saurabh S. Kumar","doi":"10.1016/j.dt.2025.01.019","DOIUrl":"10.1016/j.dt.2025.01.019","url":null,"abstract":"<div><div>In the present study, the mechanical and ballistic properties of friction stir welded (FSW) aluminum alloy (AA5754) samples were investigated, both untreated and cryogenically treated, when impacted by a 7.62 mm armour-piercing (AP) bullet at an impact velocity of 682±20 m/s. The FSW technique was used to prepare the welded samples for AA5754, with an axial force of 7 kN, a feed rate of 20 mm/min, and a speed of 1200 rpm. The cryogenic treatments performed after welding, including deep cryogenic treatment (DCT) at −196 °C and shallow cryogenic treatment (SCT) at −80 °C, for 6 and 72 h, respectively. The microstructure and mechanical characteristics of cryogenically treated and untreated joints were examined. The cryogenic treatment refined the grain size (1.05 μm) and enhanced the microhardness (93 Hv). Moreover, DCT-FSW significantly improved the tensile strength (13.93%) and impact strength (8.45%) compared to untreated FSW sample. Additionally, in untreated FSW samples, the fracture behaviour varied: the impact fracture mode primarily exhibited ductile failure, while the tensile fracture exhibited a mixed fracture mode. In contrast, the tensile and impact fracture modes of the DCT-FSW were dominated by a ductile failure mode. The DCT-FSW target demonstrated a lower depth of penetration (DOP) of 31 mm compared to the SCT-FSW and untreated FSW targets. Post-ballistic SEM analysis in the crater region of all three zones revealed the formation of frictional grooves, small cracks, and adiabatic shear bands (ASBs).</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 184-198"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829975","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hypersonic glide vehicle trajectory prediction based on frequency enhanced channel attention and light sampling-oriented MLP network","authors":"Yuepeng Cai,&nbsp;Xuebin Zhuang","doi":"10.1016/j.dt.2024.11.001","DOIUrl":"10.1016/j.dt.2024.11.001","url":null,"abstract":"<div><div>Hypersonic Glide Vehicles (HGVs) are advanced aircraft that can achieve extremely high speeds (generally over 5 Mach) and maneuverability within the Earth's atmosphere. HGV trajectory prediction is crucial for effective defense planning and interception strategies. In recent years, HGV trajectory prediction methods based on deep learning have the great potential to significantly enhance prediction accuracy and efficiency. However, it's still challenging to strike a balance between improving prediction performance and reducing computation costs of the deep learning trajectory prediction models. To solve this problem, we propose a new deep learning framework (FECA-LSMN) for efficient HGV trajectory prediction. The model first uses a Frequency Enhanced Channel Attention (FECA) module to facilitate the fusion of different HGV trajectory features, and then subsequently employs a Light Sampling-oriented Multi-Layer Perceptron Network (LSMN) based on simple MLP-based structures to extract long/short-term HGV trajectory features for accurate trajectory prediction. Also, we employ a new data normalization method called reversible instance normalization (RevIN) to enhance the prediction accuracy and training stability of the network. Compared to other popular trajectory prediction models based on LSTM, GRU and Transformer, our FECA-LSMN model achieves leading or comparable performance in terms of RMSE, MAE and MAPE metrics while demonstrating notably faster computation time. The ablation experiments show that the incorporation of the FECA module significantly improves the prediction performance of the network. The RevIN data normalization technique outperforms traditional min-max normalization as well.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 199-212"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triple point path prediction for height of burst explosion in high-altitude environment","authors":"Rui Li ,&nbsp;Minghang Hu ,&nbsp;Rui Sun ,&nbsp;Yajing Chen ,&nbsp;Yan Li ,&nbsp;Quan Wang ,&nbsp;Xiaorong Cui","doi":"10.1016/j.dt.2024.12.003","DOIUrl":"10.1016/j.dt.2024.12.003","url":null,"abstract":"<div><div>Accurately forecasting the triple point (TP) path is essential for analyzing blast loads and assessing the destructive effectiveness of the height of burst explosion. Empirical models that describe the TP path under normal temperature and pressure environments are commonly employed; however, in certain configurations, such as at high-altitudes (HAs), the environment may involve low temperature and pressure conditions. The present study develops a theoretical prediction model for the TP path under reduced pressure and temperature conditions, utilizing the image bursts method, reflected polar analysis, and dimensional analysis. The model's accuracy is evaluated through numerical simulations and experimental data. Results indicate that the prediction model effectively evaluates the TP path under diminished temperature and pressure conditions, with most predictions falling within a ±15% deviation. It was found that the TP height increases with altitude. As the altitude rises from 0 m to 10,000 m, the average TP height increases by 61.7%, 87.9%, 109.0%, and 134.3% for the scaled height of burst of 1.5 m, 2.0 m, 2.5 m, and 3.0 m, respectively. Moreover, the variation in TP height under HA environments closely mirrors that observed under corresponding reduced pressure conditions. In HA environments, only the effect of low-pressure conditions on the TP path needs to be considered, as the environmental low-temperature has a minimal effect.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 109-119"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A novel trajectories optimizing method for dynamic soaring based on deep reinforcement learning","authors":"Wanyong Zou ,&nbsp;Ni Li ,&nbsp;Fengcheng An ,&nbsp;Kaibo Wang ,&nbsp;Changyin Dong","doi":"10.1016/j.dt.2024.12.007","DOIUrl":"10.1016/j.dt.2024.12.007","url":null,"abstract":"<div><div>Dynamic soaring, inspired by the wind-riding flight of birds such as albatrosses, is a biomimetic technique which leverages wind fields to enhance the endurance of unmanned aerial vehicles (UAVs). Achieving a precise soaring trajectory is crucial for maximizing energy efficiency during flight. Existing nonlinear programming methods are heavily dependent on the choice of initial values which is hard to determine. Therefore, this paper introduces a deep reinforcement learning method based on a differentially flat model for dynamic soaring trajectory planning and optimization. Initially, the gliding trajectory is parameterized using Fourier basis functions, achieving a flexible trajectory representation with a minimal number of hyperparameters. Subsequently, the trajectory optimization problem is formulated as a dynamic interactive process of Markov decision-making. The hyperparameters of the trajectory are optimized using the Proximal Policy Optimization (PPO2) algorithm from deep reinforcement learning (DRL), reducing the strong reliance on initial value settings in the optimization process. Finally, a comparison between the proposed method and the nonlinear programming method reveals that the trajectory generated by the proposed approach is smoother while meeting the same performance requirements. Specifically, the proposed method achieves a 34% reduction in maximum thrust, a 39.4% decrease in maximum thrust difference, and a 33% reduction in maximum airspeed difference.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 99-108"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Detonation product analysis and the paradoxical performance mechanism of TKX-50: High detonation velocity with low metal acceleration","authors":"Kaiyuan Tan ,&nbsp;Yaqi Zhao ,&nbsp;Qin Liu ,&nbsp;Lixiao Hao ,&nbsp;Yushi Wen ,&nbsp;Chunliang Ji ,&nbsp;Sha Yang ,&nbsp;Haoxu Wang ,&nbsp;Luchuan Jia ,&nbsp;Jiahui Liu ,&nbsp;Zhuoping Duan ,&nbsp;Yong Han ,&nbsp;Fenglei Huang","doi":"10.1016/j.dt.2024.11.010","DOIUrl":"10.1016/j.dt.2024.11.010","url":null,"abstract":"<div><div>This study investigates the paradoxical detonation behavior of TKX-50, a nitrogen-rich energetic material, exhibiting higher detonation velocities but lower metal acceleration ability compared to HMX. Through experimental measurements and theoretical calculations, we propose a novel three-factor competition mechanism to explain this phenomenon. TKX-50-based PBX formulations achieved detonation velocities up to 9100 m/s, surpassing HMX-based counterparts. However, cylinder expansion tests revealed a 15% reduction in metal acceleration ability. Thermochemical measurements showed lower detonation heat for TKX-50 (4900 J/g) versus HMX (5645 J/g). Our mechanism involves: (1) compositional effects prevailing at high pressures; (2) Energy release becoming essential as pressure drops; (3) Pressure-dependent product composition evolution functioning at low pressure. VLW code calculations unveiled a \"crossover\" in Hugoniot curves, lending support to this mechanism. This study furnishes a new framework for comprehending the performance of nitrogen-rich energetic materials, with significant implications for the design and optimization of future high-energy density materials.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 255-266"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on multi-view collaborative detection system for UAV swarms based on Pix2Pix framework and BAM attention mechanism","authors":"Yan Ding,&nbsp;Qingxin Cao,&nbsp;Bozhi Zhang,&nbsp;Peilin Li,&nbsp;Zhongjiao Shi","doi":"10.1016/j.dt.2024.11.002","DOIUrl":"10.1016/j.dt.2024.11.002","url":null,"abstract":"<div><div>Drone swarm systems, equipped with photoelectric imaging and intelligent target perception, are essential for reconnaissance and strike missions in complex and high-risk environments. They excel in information sharing, anti-jamming capabilities, and combat performance, making them critical for future warfare. However, varied perspectives in collaborative combat scenarios pose challenges to object detection, hindering traditional detection algorithms and reducing accuracy. Limited angle-prior data and sparse samples further complicate detection. This paper presents the Multi-View Collaborative Detection System, which tackles the challenges of multi-view object detection in collaborative combat scenarios. The system is designed to enhance multi-view image generation and detection algorithms, thereby improving the accuracy and efficiency of object detection across varying perspectives. First, an observation model for three-dimensional targets through line-of-sight angle transformation is constructed, and a multi-view image generation algorithm based on the Pix2Pix network is designed. For object detection, YOLOX is utilized, and a deep feature extraction network, BA-RepCSPDarknet, is developed to address challenges related to small target scale and feature extraction challenges. Additionally, a feature fusion network NS-PAFPN is developed to mitigate the issue of deep feature map information loss in UAV images. A visual attention module (BAM) is employed to manage appearance differences under varying angles, while a feature mapping module (DFM) prevents fine-grained feature loss. These advancements lead to the development of BA-YOLOX, a multi-view object detection network model suitable for drone platforms, enhancing accuracy and effectively targeting small objects.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 213-226"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on the protection mechanism of methane explosion in underground space by flexible construction","authors":"Xianqi Duan ,&nbsp;Yulong Duan ,&nbsp;Zishuang Zhang ,&nbsp;Jun Long ,&nbsp;Yaqiao Yang ,&nbsp;Rui Lang","doi":"10.1016/j.dt.2024.12.011","DOIUrl":"10.1016/j.dt.2024.12.011","url":null,"abstract":"<div><div>Urban growth has promoted the use of underground spaces, where explosion accidents can be catastrophic. In this study, we investigated the effect of placing flexible construction in front of rigid obstacles on methane explosion protection by using an experimental platform and adjusting the blockage rate and spacing of the obstacles. It aims to reduce the risk of gas explosions in urban underground spaces. The results of the study show that the flame propagation peak speed and peak overpressure are reduced with the decrease in the blocking rate of the flexible obstacle when the blocking rate of the flexible obstacle is less than or equal to the blocking rate of the rigid obstacle, with the decrease in the spacing, the better the protection effect of the methane explosion. When the blockage rate of the flexible obstacle is greater than the blockage rate of the rigid obstacle and spacing is less than the height of the flexible obstacle, rigid and flexible obstacles are connected as a whole, increasing the strength of the explosion. This study can provide a theoretical basis and scientific guidance for optimizing rigid and flexible object hybrid layouts and methane explosion protection technology in urban underground spaces.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 169-183"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829880","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and numerical study on external explosions of cylindrical versus spherical charges at tunnel entrance","authors":"Dan Luo ,&nbsp;Jinsheng Hu ,&nbsp;Anbao Wang ,&nbsp;Xiao Yu ,&nbsp;Mengmeng Zhang ,&nbsp;Meili Yao ,&nbsp;Chun Li","doi":"10.1016/j.dt.2024.11.003","DOIUrl":"10.1016/j.dt.2024.11.003","url":null,"abstract":"<div><div>Most of the existing studies on tunnel blast wave are based on spherical or grouped charges, however, conventional weapons are mostly cylindrical rather than spherical. In order to analyze the impact of cylindrical charges on the tunnel blast wave loads and to develop a quantitative calculation method, this study carried out experimental and numerical research. Initially, external explosion experiments were conducted using both 35 kg spherical charges and cylindrical charges with aspect ratio of 4.8 at two different distances from the tunnel entrance. Comparative analysis of the blast wave parameters in the tunnel revealed that the explosive equivalent of the cylindrical charges was significantly higher than that of the spherical charges. To address this, an equivalent coefficient <em>κ</em> based on the spherical charges was proposed for the cylindrical charges. Subsequently, numerical simulations were conducted for the experimental conditions, and the numerical simulation results match the experiments well. Through numerical calculations, the reliability of the equivalent coefficient <em>κ</em> under the experimental conditions was verified, and comparison analysis indicated that the explosion energy of cylindrical charges spreads more radially, resulting in more explosion energy entering the tunnel, which is the fundamental reason for the increase in tunnel blast wave loads. Additionally, analyzing the explosion energy ratio entering the tunnel is an effective method for calculating the equivalent coefficient <em>κ</em>. Finally, through more than one hundred sets of numerical calculation results, the impact of the proportional distance <em>λ</em> and the ratio of charge mass to the tunnel cross-section dimension <em>φ</em> on the equivalence coefficients <em>κ</em> was investigated. An empirical formula for the equivalence coefficient <em>κ</em> was derived through fitting, and the accuracy of the formula was validated through literature experimental results. The research findings of this paper will provide valuable guidance for the calculation of blast wave loads in tunnel.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"46 ","pages":"Pages 227-243"},"PeriodicalIF":5.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}