Defence Technology(防务技术)最新文献

{"title":"Advancements in energetic metal-organic frameworks, alkali and alkaline earth metal salts, and transition metal complexes: Predictive models for detonation velocity, heat, and pressure","authors":"Mohammad Hossein Keshavarz,&nbsp;Nasser Hassanzadeh,&nbsp;Mohammad Jafari","doi":"10.1016/j.dt.2025.02.019","DOIUrl":"10.1016/j.dt.2025.02.019","url":null,"abstract":"<div><div>Recent advancements have led to the synthesis of various new metal-containing explosives, particularly energetic metal-organic frameworks (EMOFs), which feature high-energy ligands within well-ordered crystalline structures. These explosives exhibit significant advantages over traditional compounds, including higher density, greater heats of detonation, improved mechanical hardness, and excellent thermal stability. To effectively evaluate their detonation performance, it is crucial to have a reliable method for predicting detonation heat, velocity, and pressure. This study leverages experimental data and outputs from the leading commercial computer code to identify suitable decomposition pathways for different metal oxides, facilitating straightforward calculations for the detonation performance of alkali metal salts, and metal coordination compounds, along with EMOFs. The new model enhances predictive reliability for detonation velocities, aligning more closely with experimental results, as evidenced by a root mean square error (RMSE) of 0.68 km/s compared to 1.12 km/s for existing methods. Furthermore, it accommodates a broader range of compounds, including those containing Sr, Cd, and Ag, and provides predictions for EMOFs that are more consistent with computer code outputs than previous predictive models.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 96-112"},"PeriodicalIF":5.0,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501667","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":"Numerical simulation and experimental study on the characteristics of armature wear and contact process of small caliber railgun","authors":"Huayi Zhang ,&nbsp;Benfeng Gu ,&nbsp;Baoming Li,&nbsp;Chunxia Yang","doi":"10.1016/j.dt.2025.03.015","DOIUrl":"10.1016/j.dt.2025.03.015","url":null,"abstract":"<div><div>During the electromagnetic railgun launch process, high temperature and high current conditions can lead to armature wear, affecting armature/rail contact and degrading launch performance. This paper starts with the analysis of the metal liquid film formation at the armature/rail contact interface. 1D and 3D models are developed based on the characteristic relational equation obtained from the melt liquid film model. These models incorporate thermodynamic equilibrium phase diagram, transient heat and mass transfer model, copper-aluminum alloy reaction model, nonlinear electrical conductivity relational equation and nonlinear thermal conductivity relational equation to analyze the temperature distribution and copper-aluminum intermetallic compounds (Cu-Al IMCs) formation in the melt liquid film. The wear mechanism and influence law of armature are explained in detail from different perspectives to understand and predict the transition and gouging phenomena at the contact interface. The model's validity is confirmed by the results of electromagnetic launch experiments, providing insights for future structure design and material selection of the armature and rail.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 180-191"},"PeriodicalIF":5.0,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502718","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":"Asynchronously fault detection for flight vehicles with unstable modes via MDLF and MDADT method","authors":"Sheng Luo,&nbsp;Xin Liu,&nbsp;Yanfei Cheng,&nbsp;Shiyu Shuai,&nbsp;Haoyu Cheng","doi":"10.1016/j.dt.2025.03.016","DOIUrl":"10.1016/j.dt.2025.03.016","url":null,"abstract":"<div><div>This research focuses on detecting faults in flight vehicles with unstable subsystems operating asynchronously. By accounting for asynchronous switching, a switched model is established, and filters for fault detection (FD) in unstable subsystems are developed. The FD challenge is then transformed into an <em>H∞</em> filtering issue. Utilizing the multiple discontinuous Lyapunov function (MDLF) approach and the mode-dependent average dwell time (MDADT) method, sufficient conditions are derived to ensure stability during both fast and slow switching. Furthermore, the existence and solutions for FD filters are provided through linear matrix inequalities (LMIs). The simulation outcomes demonstrated the excellent performance of the developed method in studied cases.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 417-436"},"PeriodicalIF":5.0,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501636","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":"Performance of multi-layer steel fiber-reinforced mortar panels with air gaps against high-velocity bullets and successive firing","authors":"Apisit Techaphatthanakon ,&nbsp;Buchit Maho ,&nbsp;Sittisak Jamnam ,&nbsp;Pochara Kruavit ,&nbsp;Manote Sappakittipakorn ,&nbsp;Phattharachai Pongsopha ,&nbsp;Gritsada Sua-iam ,&nbsp;Piti Sukontasukkul","doi":"10.1016/j.dt.2025.03.012","DOIUrl":"10.1016/j.dt.2025.03.012","url":null,"abstract":"<div><div>This research addresses the growing demand for high-performance protective materials against high-velocity projectile impacts. The performance of multi-layered steel fiber-reinforced mortar (SFRM) panels with varying thicknesses and air gaps, was experimentally investigated under single and repeated impacts of 7.62×51 mm bullets fired from a distance of 50 m. The impact events were recorded using a high-speed camera at 40000 fps. Panel performance was assessed in terms of failure modes, kinetic energy absorption, spalling diameter, and percentage of back-face damage area, and weight loss. Results showed that panel configuration significantly influenced performance. Panel P10, with 70 mm SFRM thickness and 20 mm air gaps, provided the highest resistance, dissipating 5223 J of kinetic energy and preventing back-face damage. In contrast, P7, which absorbed 4476 J, presented a back damage area percentage of 8.93% after three impacts. Weight loss analysis further confirmed durability improvements, with P10 showing only 1.53% cumulative loss compared to 3.26% in P7. The inclusion of wider air gaps enhanced energy dissipation and reduced damage. Comparison between single and repeated impacts demonstrated the sustained resistance of high-performance panels, with P10 maintaining minimal degradation across three consecutive impacts. These findings highlight the potential of multi-layer SFRM panels to enhance ballistic resistance, making them suitable for military, security, and civilian protective applications requiring long-term durability.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 290-306"},"PeriodicalIF":5.0,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502707","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 navigation method of high speed differential rotation guided ammunition with ballistic assistance prediction under GNSS denial","authors":"Ning Liu ,&nbsp;Kejun Hu ,&nbsp;Bin Hu ,&nbsp;Haorui Li ,&nbsp;Kai Shen ,&nbsp;Wenhao Qi ,&nbsp;Junfang Fan ,&nbsp;Zhong Su","doi":"10.1016/j.dt.2025.03.013","DOIUrl":"10.1016/j.dt.2025.03.013","url":null,"abstract":"<div><div>In complex environments such as high dynamics and weak signals, a satellite signal compensation method based on prefabricated trajectory assistance and an improved adaptive Kalman filter is proposed for a 155 mm differential rotating rear-body control-guided projectile to address the situation of satellite signal flickering and loss in projectile navigation systems due to environmental limitations. First, establish the system state and measurement equation when receiving satellite signals normally. Second, a seven-degree-of-freedom external ballistic model is constructed, and the ideal trajectory output from the ballistic model is used to provide the virtual motion state of the projectile, which is input into a filter as a substitute observation when satellite signals are lost. Finally, an adaptive Kalman filter (AKF) is designed, the proposed adaptive Kalman filter can accurately adjust the estimation error covariance matrix and Kalman gain in real-time based on information covariance mismatch. The simulation results show that compared to the classical Kalman filter, it can reduce the average positioning error by more than 38.21% in the case of short-term and full-range loss of satellite signals, providing a new idea for the integrated navigation of projectiles with incomplete information under the condition of satellite signal loss.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 275-289"},"PeriodicalIF":5.0,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502716","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":"Mitigation strategies for blasting-induced cracks and vibrations in twin-arch tunnel structures","authors":"Xianshun Zhou ,&nbsp;Jin Chen ,&nbsp;Xuemin Zhang ,&nbsp;Kai Zhu ,&nbsp;Yanyong Zhang ,&nbsp;Jianbo Fei ,&nbsp;Muhammad Irslan Khalid","doi":"10.1016/j.dt.2025.03.009","DOIUrl":"10.1016/j.dt.2025.03.009","url":null,"abstract":"<div><div>Due to space constraints in mountainous areas, twin tunnels are sometimes constructed very close to each other or even overlap. This proximity challenges the structural stability of tunnels built with the drill-and-blast method, as the short propagation distance amplifies blasting vibrations. A case of blasting damage is reported in this paper, where concrete cracks crossed construction joints in the twin-arch lining. To identify the causes of these cracks and develop effective vibration mitigation measures, field monitoring and numerical analysis were conducted. Specifically, a restart method was used to simulate the second peak particle velocity (PPV) of MS3 delays occurring 50 ms after the MS1 delays. The study found that the dynamic tensile stress in the tunnel induced by the blast wave has a linear relationship with the of the product of the concrete wave impedance and the PPV. A blast vibration velocity exceeding 23.3 cm/s resulted in tensile stress in the lining surpassing the ultimate tensile strength of C30 concrete, leading to tensile cracking on the blast-facing arch of the constructed tunnel. To control excessive vibration velocity, a mitigation trench was implemented to reduce blast wave impact. The trench, approximately 15 m in length, 50 cm in width, and 450 cm in height, effectively lowered vibration velocities, achieving an average reduction rate of 52% according to numerical analysis. A key innovation of this study is the on-site implementation and validation of the trench's effectiveness in mitigating vibrations. A feasible trench construction configuration was proposed to overcome the limitations of a single trench in fully controlling vibrations. To further enhance protection, zoned blasting and an auxiliary rock pillar, 80 cm in width, were incorporated to reinforce the mid-wall. This study introduces novel strategies for vibration protection in tunnel blasting, offering innovative solutions to address blasting-induced vibrations and effectively minimize their impact, thereby enhancing safety and structural stability.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 242-259"},"PeriodicalIF":5.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502705","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":"Application of gurney and flight of fragment calculations for water jet velocities in explosive applications","authors":"Rachel L. Bauer,&nbsp;Tate B. Friedrich,&nbsp;Catherine E. Johnson","doi":"10.1016/j.dt.2025.03.010","DOIUrl":"10.1016/j.dt.2025.03.010","url":null,"abstract":"<div><div>This study investigates the application of Gurney and flight of fragment equations, typically used to predict metal fragment velocities, in modeling the water jet behavior. Three shotgun cartridge sizes were used as the energy source: 2.59 g, 5.83 g, and 7.13 g. Two configurations were tested: standard (full-barrel water load) and \"negative 8\" (partial water load). High-speed footage captured water column velocities, and Gurney models, including infinitely tamped and open-faced configurations, combined with the flight of fragment model were used to assess prediction accuracy. Results showed charge strength significantly affects water column velocity, with higher strengths yielding greater stability and velocity retention over distance. The infinitely tamped Gurney model closely predicted experimental velocities, deviating by as little as 1.4% for standard charges and 2.8% for negative 8 charges. Additionally, interesting dynamics such as a 1–2° rise in jet height and the rear overtaking the front was observed. These findings have significant implications for optimizing PAN disruptors and enhancing performance in high-velocity fluid applications and explosive breaching systems.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 68-78"},"PeriodicalIF":5.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502712","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":"Investigation on dynamic response of liquid-filled cylindrical shell structures under the action of combined blast and fragments loading","authors":"Zhujie Zhao ,&nbsp;Hailiang Hou ,&nbsp;Dian Li ,&nbsp;Xiaowei Wu ,&nbsp;Yongqing Li ,&nbsp;Zhenghan Chen ,&nbsp;Linzhi Wu","doi":"10.1016/j.dt.2025.03.007","DOIUrl":"10.1016/j.dt.2025.03.007","url":null,"abstract":"<div><div>This study designs four types of liquid-filled cylindrical shell structures to investigate their protection characteristics against explosive shock waves and high-speed fragments. Bare charge and charge-driven prefabricated fragments are employed to examine the damage under blast shock waves and combined blast and fragments loading on various liquid-filled cylindrical shell structures. The test results are compared to numerical calculations and theoretical analysis for the structure's deformation, the liquid medium's movement, and the pressure waves' propagation characteristics under different liquid-filling methods. The results showed that the filling method influences the blast protection and the structure's energy absorption performance. The external filling method reduces the structural deformation, and the internal filling method increases the damage effect. The gapped internal filling method improves the structure's energy absorption efficiency. The pressure wave loading on the liquid-filled cylindrical shell structure differs depending on filling methods. Explosive shock waves and high-speed fragments show a damage enhancement effect on the liquid-filled cylindrical shell structure, depending on the thickness of the internal liquid container layer. The specific impulse on the inner surface of the cylindrical shell positively correlates to the radial deformation of the cylindrical shell structure, and the external liquid layer limits the radial structural deformation.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 334-354"},"PeriodicalIF":5.0,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501632","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":"Realizing high-speed target tracking by using multi-rate feedforward predictive control for the acquisition, tracking, and pointing system","authors":"Hang Li ,&nbsp;Gaoliang Peng ,&nbsp;Xiaobiao Shan ,&nbsp;Mingyuan Zhao ,&nbsp;Wei Zhang ,&nbsp;Jinghan Wang ,&nbsp;Feng Cheng","doi":"10.1016/j.dt.2025.03.008","DOIUrl":"10.1016/j.dt.2025.03.008","url":null,"abstract":"<div><div>The acquisition, tracking, and pointing (ATP) system is widely used in target tracking, counter-UAV operations, and other related fields. As UAV technology develops, there is a growing demand to enhance the tracking capabilities of ATP systems. However, in practical applications, ATP systems face various design constraints and functional limitations, making it infeasible to indefinitely improve hardware performance to meet tracking requirements. As a result, tracking algorithms are required to execute increasingly complex tasks. This study introduces a multi-rate feedforward predictive controller to address issues such as low image feedback frequency and significant delays in ATP systems, which lead to tracking jitter, poor tracking performance, low precision, and target loss. At the same time, the proposed approach aims to improve the tracking capabilities of ATP systems for high-speed and highly maneuverable targets under conditions of low sampling feedback rates and high feedback delays. The method suggested is also characterized by its low order, fast response, and robustness to model parameter variations. In this study, an actual ATP system is built for target tracking test, and the proposed algorithm is fully validated in terms of simulation and actual system application verification. Results from both simulations and experiments demonstrate that the method effectively compensates for delays and low sampling rates. For targets with relative angular velocities ranging from 0 to 90°/s and angular accelerations between 0 and 470°/s², the system improved tracking accuracy by 70.0%–89.9% at a sampling frequency of 50 Hz and a delay of 30 m s. Moreover, the compensation algorithm demonstrated consistent performance across actuators with varying characteristics, further confirming its robustness to model insensitivity. In summary, the proposed algorithm considerably enhances the tracking accuracy and capability of ATP systems for high-speed and highly maneuverable targets, reducing the probability of target loss from high speed. This approach offers a practical solution for future multi-target tracking across diverse operational scenarios.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 137-151"},"PeriodicalIF":5.0,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502714","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":"Investigation of blasting effects and mechanisms on concrete frustums under side-contact explosions","authors":"Gengxin Kang ,&nbsp;Yadong Zhang ,&nbsp;Xingbo Xie ,&nbsp;Wenbin Gu","doi":"10.1016/j.dt.2025.03.005","DOIUrl":"10.1016/j.dt.2025.03.005","url":null,"abstract":"<div><div>Investigating the blast effects and mechanisms on typical finite-sized obstacles is essential for optimizing defense strategies and designing more robust barriers to deter terrorists and protect critical locations. This study investigates the blasting effects and underlying mechanisms of concrete frustums subjected to contact explosions, employing both numerical simulations and field tests. It focuses on the effects of top and side blasting, with particular emphasis on fracture modes, damage patterns, and fragment sizes, as well as the causes of different failure modes and the propagation of stress waves. The study also explores the blasting effects of detonating explosives at varying positions along the side and with different charge amounts. The results show that side-blasting leads to complete fragmentation, with tensile waves playing a significant role in creating extensive damage zones that propagate parallel to the frustum's outer surface, concentrating damage near the surface. During top-blasting, the upper half of the frustum undergoes fragmentation, while the lower half experiences cracking. Tensile waves propagate from the top to the bottom surface, forming larger blocks in regions with lower wave intensity. Three distinct damage zones within the frustum were identified, and a series of mathematical formulas were derived to describe the relationship between the maximum fragment size and charge mass. As the charge mass increased from 1.0 kg to 4.0 kg, the maximum fragment size decreased. Detonation at the center of the frustum's side resulted in the most severe fragmentation, with a 51.8% reduction in fragment size compared to other detonation positions. Finally, four broken modes were classified, each influenced by charge mass and explosive location. This study provides valuable insights for optimizing civil blasting operations and designing protective engineering structures.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 113-127"},"PeriodicalIF":5.0,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144502708","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}