Defence Technology(防务技术)最新文献

{"title":"Oscillation mechanism and predictive model of explosion load for natural gas in confined tube","authors":"Chengjun Yue,&nbsp;Li Chen,&nbsp;Linfeng Xu","doi":"10.1016/j.dt.2024.09.003","DOIUrl":"10.1016/j.dt.2024.09.003","url":null,"abstract":"<div><div>Gas explosion in confined space often leads to significant pressure oscillation. It is widely recognized that structural damage can be severe when the oscillation frequency of the load resonates with the natural vibration frequency of the structure. To reveal the oscillation mechanism of gas explosion load, the experiment of gas explosion was conducted in a large-scale confined tube with the length of 30 m, and the explosion process was numerically analyzed using FLACS. The results show that the essential cause of oscillation effect is the reflection of the pressure wave. In addition, due to the difference in the propagation path of the pressure wave, the load oscillation frequency at the middle position of the tunnel is twice that at the end position. The average sound velocity can be used to calculate the oscillation frequency of overpressure accurately, and the error is less than 15%. The instability of the flame surface and the increase of flame turbulence caused by the interaction between the pressure wave and the flame surface are the main contributors to the increase in overpressure and amplitude. The overpressure peaks calculated by the existing flame instability model and turbulence disturbance model are 31.7% and 34.7% lower than the numerical results, respectively. The turbulence factor model established in this work can describe the turbulence enhancement effect caused by flame instability and oscillatory load, and the difference between the theoretical and numerical results is only 4.6%. In the theoretical derivation of the overpressure model, an improved model of dynamic turbulence factor is established, which can describe the enhancement effect of turbulence factor caused by flame instability and self-turbulence. Based on the one-dimensional propagation theory of pressure wave, the oscillatory effect of the load is derived to calculate the frequency and amplitude of pressure oscillation. The average error of amplitude and frequency is less than 20%.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"45 ","pages":"Pages 13-27"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and implementation of a high-performance miniaturized multi-layer magnetic shielding spherical shell with minimal pores based on target magnetic field","authors":"Wanqing Li ,&nbsp;Wei Li ,&nbsp;Shaotao Qu ,&nbsp;Shuyi Zhang ,&nbsp;Jingyang Xu","doi":"10.1016/j.dt.2024.09.005","DOIUrl":"10.1016/j.dt.2024.09.005","url":null,"abstract":"<div><div>Achieving the spin-exchange relaxation-free (SERF) state in atomic comagnetometers (ACMs) necessitates a stable and weak magnetic environment. This paper presents the design of a miniaturized permalloy magnetic shielding spherical shell (MSSS) with minimal apertures, tailored to meet these requirements. By employing a combination of analytical solutions and finite element analysis (FEA), we achieved superior magnetic shielding while maintaining a compact form factor. The analytical solution for the shielding factor indicated that a four-layer permalloy sphere shell with optimized air gaps was necessary. A numerical analysis model of the MSSS was developed and validated using COMSOL software, confirming the suitability of the air gaps. The size, shape, and orientation of the openings in the perforated sphere shell were meticulously designed and optimized to minimize residual magnetism. The optimal structure was fabricated, resulting in triaxial shielding factors of 47619, 52631, and 21739, meeting the anticipated requirements. A comparison of simulation results with experimental tests demonstrated the efficacy of the design methodology. This study has significant implications for ultra-sensitive magnetic field detection devices requiring weak magnetic field environments, such as atomic gyroscopes, magnetometers, atomic interferometers, and atomic clocks.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"45 ","pages":"Pages 99-108"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reactivity of polyaniline composites with attractive cyclic nitramines","authors":"Veerabhadragouda B. Patil ,&nbsp;Roman Svoboda ,&nbsp;Svatopluk Zeman","doi":"10.1016/j.dt.2024.10.009","DOIUrl":"10.1016/j.dt.2024.10.009","url":null,"abstract":"<div><div>Composite microcrystals of the nitramines (NAs) viz., RDX, HMX, BCHMX, and CL-20 with electrically conductive polyaniline (PANi) are a charge transfer complexes in coagglomerated composite crystals (CACs). The activation energies of thermolysis, <em>E</em>_a, of the pure NAs and their PANi-CACs were determined using the Kissinger method, and decomposition processes are discussed. Except for the RDX/PANi CACs, all the other CACs show higher <em>E</em>_a values for decomposition compared to their pure NA counterparts. For all CACs, relationships are specified between the <em>E</em>_a values, on the one hand, and the squares of the detonation velocities, enthalpies of formation, spark energy and impact sensitivities, on the other. The relationships between their low-temperature heats of decomposition, Δ<em>H</em>, from DSC, and their enthalpy of formation, logarithm of impact sensitivity, electric spark energy, as well as detonation energy, are described. The PANi favorably influences the density of the corresponding CACs; surprisingly close linear correlations were found, and explained, between these densities and the <em>E</em>_a values. This presence of PANi strongly increased the electrical spark sensitivity of the CACs in comparison to the base NAs. Based on the results obtained, it can be noted in particular the exceptional desensitization of HMX to impact and the increased sensitivity to electrical spark by coating its crystals with polyaniline.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"45 ","pages":"Pages 1-12"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research status of high efficiency deep penetration welding of medium-thick plate titanium alloy: A review","authors":"Zhihai Dong ,&nbsp;Ye Tian ,&nbsp;Long Zhang ,&nbsp;Tong Jiang ,&nbsp;Dafeng Wang ,&nbsp;Yunlong Chang ,&nbsp;Donggao Chen","doi":"10.1016/j.dt.2024.08.004","DOIUrl":"10.1016/j.dt.2024.08.004","url":null,"abstract":"<div><div>Titanium alloy has the advantages of high strength, strong corrosion resistance, excellent high and low temperature mechanical properties, etc., and is widely used in aerospace, shipbuilding, weapons and equipment, and other fields. In recent years, with the continuous increase in demand for medium-thick plate titanium alloys, corresponding welding technologies have also continued to develop. Therefore, this article reviews the research progress of deep penetration welding technology for medium-thick plate titanium alloys, mainly covering traditional arc welding, high-energy beam welding, and other welding technologies. Among many methods, narrow gap welding, hybrid welding, and external energy field assistance welding all contribute to improving the welding efficiency and quality of medium-thick plate titanium alloys. Finally, the development trend of deep penetration welding technology for medium-thick plate titanium alloys is prospected.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"45 ","pages":"Pages 178-202"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142189178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preparation of spherical HMX@PDA-based PBX by co-axial droplet microfluidic technology: Enhancing the interfacial effect and safety performance of composite microspheres","authors":"Yunyan Guo ,&nbsp;Yi Liu ,&nbsp;Jiani Xie ,&nbsp;Jiawei Li ,&nbsp;Fan Wang ,&nbsp;Jinshan Lei ,&nbsp;Chongwei An ,&nbsp;Zhongliang Ma ,&nbsp;Bidong Wu","doi":"10.1016/j.dt.2024.10.010","DOIUrl":"10.1016/j.dt.2024.10.010","url":null,"abstract":"<div><div>Surface engineering plays a crucial role in improving the performance of high energy materials, and polydopamine (PDA) is widely used in the field of energetic materials for surface modification and functionalization. In order to obtain high-quality HMX@PDA-based PBX explosives with high sphericity and a narrow particle size distribution, composite microspheres were prepared using co-axial droplet microfluidic technology. The formation mechanism, thermal behavior, mechanical sensitivity, electrostatic spark sensitivity, compressive strength, and combustion performance of the microspheres were investigated. The results show that PDA can effectively enhance the interfacial interaction between the explosive particles and the binder under the synergistic effect of chemical bonds and the physical \"mechanical interlocking\" structure. Interface reinforcement causes the thermal decomposition temperature of the sample microspheres to move to a higher temperature, with the sensitivity to impact, friction, and electrostatic sparks (for S-1) increasing by 12.5%, 31.3%, and 81.5% respectively, and the compressive strength also increased by 30.7%, effectively enhancing the safety performance of the microspheres. Therefore, this study provides an effective and universal strategy for preparing high-quality functional explosives, and also provides some reference for the safe use of energetic materials in practical applications.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"45 ","pages":"Pages 73-83"},"PeriodicalIF":5.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effective implementation of controlled blasting methodology during excavation of hard rock in the close proximity of earthen dam and tunnel","authors":"Prakash K. Palei,&nbsp;Vijay K. Ghodake,&nbsp;S. Santhosh Kumar,&nbsp;R.S. Gurjar,&nbsp;Chaman Singh,&nbsp;M. Meena,&nbsp;Rizwan Ali,&nbsp;R.S. Kankara","doi":"10.1016/j.dt.2025.02.026","DOIUrl":"10.1016/j.dt.2025.02.026","url":null,"abstract":"<div><div>The present technical paper outlines the details of the controlled blasting techniques used to optimize blasting pattern for excavation of hard rock near the Bhira Earthen Dam in Maharashtra, India. In this connection, a series of experimental blasts were conducted by adjusting various blast design parameters at project site. The safe charge weight per delay was kept between 0.125 and 0.375 kg. The outcomes of these experimental blasts were analyzed to recommend optimized blasting patterns and methods for the overall excavation process during actual blasting operations. Blast design parameters, including the maximum quantity of explosive per delay, hole depth, burden and spacing between holes were optimized by using a site-specific attenuation equation, taking into account the proximity of the dam and tunnel from the blasting area. Peak particle velocity (PPV) level of 10 mm/s and 50 mm/s respectively were adopted as the safe vibration level for ensuring safety of the Bhira Earthen Dam and the nearby tunnel from the adverse effects of blast vibrations by analyzing the dominant frequency of ground vibrations observed and also by reviewing various international standards. Frequency of the ground vibrations observed on the dam and tunnel from majority of the blasts was found to be more than 10 Hz and 50 Hz respectively. During the entire period of blasting, the blast vibrations were recorded to be far lower than the safe vibration level set for these structures. Maximum Vibration level of about 0.8 mm/s and 35 mm/s were observed on dam and tunnel respectively which are far lower than the safe vibration level adopted for these structures. Hence, the entire excavation work was completed successfully and safely, without endangering the safety of dam or tunnel.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 306-316"},"PeriodicalIF":5.0,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139657","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":"Advanced composite wing design for next-generation military UAVs: A progressive numerical optimization framework","authors":"M. Atif Yilmaz ,&nbsp;Kemal Hasirci ,&nbsp;Berk Gündüz ,&nbsp;Alaeddin Burak Irez","doi":"10.1016/j.dt.2025.02.020","DOIUrl":"10.1016/j.dt.2025.02.020","url":null,"abstract":"<div><div>The design of unmanned aerial vehicles (UAVs) revolves around the careful selection of materials that are both lightweight and robust. Carbon fiber-reinforced polymer (CFRP) emerged as an ideal option for wing construction, with its mechanical qualities thoroughly investigated. In this study, we developed and optimized a conceptual UAV wing to withstand structural loads by establishing progressive composite stacking sequences, and we conducted a series of experimental characterizations on the resulting material. In the optimization phase, the objective was defined as weight reduction, while the Hashin damage criterion was established as the constraint for the optimization process. The optimization algorithm adaptively monitors regional damage criterion values, implementing necessary adjustments to facilitate the mitigation process in a cost-effective manner. Optimization of the analytical model using Simulia Abaqus™ and a Python-based user-defined sub-routine resulted in a 34.7% reduction in the wing's structural weight after 45 iterative rounds. Then, the custom-developed optimization algorithm was compared with a genetic algorithm optimization. This comparison has demonstrated that, although the genetic algorithm explores numerous possibilities through hybridization, the custom-developed algorithm is more result-oriented and achieves optimization in a reduced number of steps. To validate the structural analysis, test specimens were fabricated from the wing's most critically loaded segment, utilizing the identical stacking sequence employed in the optimization studies. Rigorous mechanical testing revealed unexpectedly high compressive strength, while tensile and bending strengths fell within expected ranges. All observed failure loads remained within the established safety margins, thereby confirming the reliability of the analytical predictions.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 141-155"},"PeriodicalIF":5.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139573","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":"One-pot synthesis of PDDA-mediated CuO-functionalized activated carbon fabric for sarin detoxification with enhanced strength and permeability for NBC protective clothing","authors":"Himanshi Dhyani ,&nbsp;Ravindra V. Adivarekar ,&nbsp;Vikas B. Thakare ,&nbsp;Suraj Bharati ,&nbsp;Ajay Dixit ,&nbsp;G. Raviraju ,&nbsp;Prabhat Garg","doi":"10.1016/j.dt.2025.02.014","DOIUrl":"10.1016/j.dt.2025.02.014","url":null,"abstract":"<div><div>Chemical warfare agents (CWAs) are extremely lethal substances used in warfare and terrorism, capable of causing permanent damage even in small doses, despite medical intervention. Therefore, detection, protection, and detoxification of CWAs are vital for the safety of first responders, military personnel, and civilians, driving significant research in this area. Herein, we designed and synthesized a poly(diallyldimethylammonium chloride) (PDDA) mediated cupric oxide (CuO) functionalized activated carbon fabric (ACF), termed ACF@PDDA-CuO, as an adsorbent filter material for self-detoxifying chemical protective clothing. PDDA, a positively charged polyelectrolyte, effectively binds in-situ synthesized CuO to the negatively charged ACF surface, serving as a suitable binder. This study demonstrates the synergistic effects of PDDA-CuO functionalization on ACF, where PDDA treatment enhanced mechanical and comfort properties, and CuO crystal growth significantly improved detoxification efficacy against the CWA Nerve Agent Sarin. Comprehensive analyses, including FTIR, BET surface area analysis, SEM, EDS, TEM, STEM, TGA, XPS, and XRD, confirmed the uniform deposition of CuO and PDDA on the ACF surface. The Cu content on ACF@PDDA-CuO samples was measured via iodometric titration. The materials were evaluated for tensile strength, air permeability, water vapor permeability, nerve agent (Sarin) detoxification, and blister agent (Sulfur Mustard) breakthrough time to assess their applicability for protective clothing. The optimized PDDA-CuO on ACF detoxified 82.04% of Sarin within 18 h, compared to 25.22% by ACF alone, and enhanced tensile strength by 23.67%, air permeability by 24.63%, and water vapor permeability by 3.94%, while maintaining protection against Sulfur Mustard for 24 h. These findings indicate that ACF@PDDA-CuO is a promising candidate for CWA protective clothing, offering robust protection with enhanced comfort.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 67-82"},"PeriodicalIF":5.0,"publicationDate":"2025-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139665","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":"The damage of sequential explosions in reinforced concrete: Experimental and numerical investigation","authors":"Libin Wang ,&nbsp;Zhun Bai ,&nbsp;Bingwen Qian ,&nbsp;Yutao Hu ,&nbsp;Liangquan Wang ,&nbsp;Gang Zhou","doi":"10.1016/j.dt.2025.02.012","DOIUrl":"10.1016/j.dt.2025.02.012","url":null,"abstract":"<div><div>The development of guidance technology has made it possible for the earth penetration weapons (EPWs) to impact the target repeatedly at a close range. To investigative the damage of single and sequential strike induced by the EPWs, experimental and numerical investigations are carried out in this paper. Firstly, a series of sequential explosion tests are conducted to provide the basic data of the crater size. Then, a numerical model is established to simulate the damage effects of sequential explosions using the meshfree method of Smoothed particle Galerkin. The effectiveness of numerical model is verified by comparison with the experimental results. Finally, based on dimensional analysis, several empirical formulas for describing the crater size are presented, including the conical crater diameter and the conical crater depth of the single explosion, the conical crater area and the joint depth of the secondary explosion. The formula for the single explosion expresses the relationship between the aspect ratio of the charge ranging from 3 to 7, the dimensionless buried depth ranging from 2 to 14 and the crater size. The formula for the secondary explosion expresses the relationship between the relative position of the two explosions and the crater size. All of data can provide reference for the design of protective structures.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 284-297"},"PeriodicalIF":5.0,"publicationDate":"2025-02-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139655","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":"Trajectory prediction algorithm of ballistic missile driven by data and knowledge","authors":"Hongyan Zang,&nbsp;Changsheng Gao,&nbsp;Yudong Hu,&nbsp;Wuxing Jing","doi":"10.1016/j.dt.2025.02.001","DOIUrl":"10.1016/j.dt.2025.02.001","url":null,"abstract":"<div><div>Recently, high-precision trajectory prediction of ballistic missiles in the boost phase has become a research hotspot. This paper proposes a trajectory prediction algorithm driven by data and knowledge (DKTP) to solve this problem. Firstly, the complex dynamics characteristics of ballistic missile in the boost phase are analyzed in detail. Secondly, combining the missile dynamics model with the target gravity turning model, a knowledge-driven target three-dimensional turning (T3) model is derived. Then, the BP neural network is used to train the boost phase trajectory database in typical scenarios to obtain a data-driven state parameter mapping (SPM) model. On this basis, an online trajectory prediction framework driven by data and knowledge is established. Based on the SPM model, the three-dimensional turning coefficients of the target are predicted by using the current state of the target, and the state of the target at the next moment is obtained by combining the T3 model. Finally, simulation verification is carried out under various conditions. The simulation results show that the DKTP algorithm combines the advantages of data-driven and knowledge-driven, improves the interpretability of the algorithm, reduces the uncertainty, which can achieve high-precision trajectory prediction of ballistic missile in the boost phase.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 187-203"},"PeriodicalIF":5.0,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139076","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}