Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.06.015
Mengli Yin, Haoyang Guo, Erhai An, Kangjie Xie, Zijia Wang, Tengyue Song, Xiong Cao
RDX/Al mixtures are widely utilized in energetic materials, yet their hybrid dust generated during production and application poses potential explosion hazards. Moreover, the synergistic explosion mechanisms remain poorly understood, particularly at varying dust concentrations. This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations (300 g/m3, 600 g/m3, 900 g/m3) on RDX dust explosion severity, flame propagation behavior, and gaseous products. The results indicate that the maximum explosion pressure peaks at 35% RDX, 65% RDX, and 80% RDX at 300 g/m3, 600 g/m3, and 900 g/m3, respectively. Concurrently, the time for the flame to propagate to the wall (t1) reaches minimum values of 34.8 ms, 25.66 ms, and 23.93 ms. The maximum rate of pressure rise is observed for pure RDX at 900 g/m3. Aluminum powder enhances flame propagation velocity and combustion duration, as validated by the flame propagation system. Overall, the concentrations of carbon oxides (CO+CO2) decrease significantly with increasing aluminum mass percentage. At 20% RDX, the concentrations decreased by 51.64%, 72.31%, and 79.55% compared to pure RDX at 300 g/m3, 600 g/m3, and 900 g/m3, respectively. Notably, N2O concentration only at 300 g/m3 showed such a trend. It rises first and then falls at 35% RDX at 600 g/m3 and 900 g/m3. These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.
{"title":"Proportional effects of RDX/Al mixtures on dust explosion characteristics, flame behavior, and explosion mechanism","authors":"Mengli Yin, Haoyang Guo, Erhai An, Kangjie Xie, Zijia Wang, Tengyue Song, Xiong Cao","doi":"10.1016/j.dt.2025.06.015","DOIUrl":"10.1016/j.dt.2025.06.015","url":null,"abstract":"<div><div>RDX/Al mixtures are widely utilized in energetic materials, yet their hybrid dust generated during production and application poses potential explosion hazards. Moreover, the synergistic explosion mechanisms remain poorly understood, particularly at varying dust concentrations. This study systematically investigates the effects of different aluminum powder mass percentages and dust concentrations (300 g/m<sup>3</sup>, 600 g/m<sup>3</sup>, 900 g/m<sup>3</sup>) on RDX dust explosion severity, flame propagation behavior, and gaseous products. The results indicate that the maximum explosion pressure peaks at 35% RDX, 65% RDX, and 80% RDX at 300 g/m<sup>3</sup>, 600 g/m<sup>3</sup>, and 900 g/m<sup>3</sup>, respectively. Concurrently, the time for the flame to propagate to the wall (<em>t</em><sub>1</sub>) reaches minimum values of 34.8 ms, 25.66 ms, and 23.93 ms. The maximum rate of pressure rise is observed for pure RDX at 900 g/m<sup>3</sup>. Aluminum powder enhances flame propagation velocity and combustion duration, as validated by the flame propagation system. Overall, the concentrations of carbon oxides (CO+CO<sub>2</sub>) decrease significantly with increasing aluminum mass percentage. At 20% RDX, the concentrations decreased by 51.64%, 72.31%, and 79.55% compared to pure RDX at 300 g/m<sup>3</sup>, 600 g/m<sup>3</sup>, and 900 g/m<sup>3</sup>, respectively. Notably, N<sub>2</sub>O concentration only at 300 g/m<sup>3</sup> showed such a trend. It rises first and then falls at 35% RDX at 600 g/m<sup>3</sup> and 900 g/m<sup>3</sup>. These findings elucidate the synergistic explosion mechanisms and provide critical guidelines for safe production and handling.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 71-83"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277879","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.06.016
Jie Fu , Qiang Liu , Xiao Liu , Yanqin Zhang
The electric vertical takeoff and landing (eVTOL) aircraft shows great potential for rapid military personnel deployment on the battlefield. However, its susceptibility to control loss, complex crashes, and extremely limited bottom energy-absorbing space demands higher comprehensive crashworthiness of its subfloor thin-walled structures. This study investigated the energy absorption capacity of novel concave polygonal carbon fiber reinforced plastics (CFRP) tubes under multi-angle collisions. Quasi-static compression experiments and finite element simulations were conducted to assess the failure mode and energy absorption. The influences of cross-section shapes, loading conditions, and geometry parameters on crashworthiness metrics were further analyzed. The results revealed that, under the similar weight, concave polygonal tubes exhibited superior energy absorption under axial loads compared to regular polygonal and circular tubes, attributed to the increased number of axial splits. However, both regular and concave polygonal tubes, particularly the latter, demonstrated reduced oblique energy absorption compared to traditional square tubes with the increasing ratio of SEA value decreased from 20%−16%. Notably, this reduction in energy absorption can be compensated for by the implementation of inward and outward crusher plugs, and with them, the concave polygonal tubes demonstrated outstanding overall crashworthiness performance under multiple loading conditions. This concave cross-sectional design methods could serve as a guidance for the development of the eVTOL subfloor.
{"title":"Crashworthiness design of concave polygonal CFRP tubes for eVTOL applications under multi-angle compression loading","authors":"Jie Fu , Qiang Liu , Xiao Liu , Yanqin Zhang","doi":"10.1016/j.dt.2025.06.016","DOIUrl":"10.1016/j.dt.2025.06.016","url":null,"abstract":"<div><div>The electric vertical takeoff and landing (eVTOL) aircraft shows great potential for rapid military personnel deployment on the battlefield. However, its susceptibility to control loss, complex crashes, and extremely limited bottom energy-absorbing space demands higher comprehensive crashworthiness of its subfloor thin-walled structures. This study investigated the energy absorption capacity of novel concave polygonal carbon fiber reinforced plastics (CFRP) tubes under multi-angle collisions. Quasi-static compression experiments and finite element simulations were conducted to assess the failure mode and energy absorption. The influences of cross-section shapes, loading conditions, and geometry parameters on crashworthiness metrics were further analyzed. The results revealed that, under the similar weight, concave polygonal tubes exhibited superior energy absorption under axial loads compared to regular polygonal and circular tubes, attributed to the increased number of axial splits. However, both regular and concave polygonal tubes, particularly the latter, demonstrated reduced oblique energy absorption compared to traditional square tubes with the increasing ratio of SEA value decreased from 20%−16%. Notably, this reduction in energy absorption can be compensated for by the implementation of inward and outward crusher plugs, and with them, the concave polygonal tubes demonstrated outstanding overall crashworthiness performance under multiple loading conditions. This concave cross-sectional design methods could serve as a guidance for the development of the eVTOL subfloor.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 100-115"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145278355","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}
Accurate characterization of three-dimensional burning crack propagation remains pivotal yet challenging for energetic material safety, as conventional diagnostics and models inadequately resolve coupled crack-pressure dynamics in confined explosives. This study combines a novel spherical confinement system (with/without sapphire windows) with synchronized high-speed imaging and 3D reconstruction to overcome optical limitations in opaque explosives. Experimental analysis of centrally ignited HMX-based PBX-1 reveals: (1) burning cracks propagate radially with equatorial acceleration and polar deceleration, (2) systematic formation of 3–4 dominant crack branches across geometries, and (3) pressure evolution exhibiting gradual accumulation (subsurface cracking) followed by exponential growth (surface burn-through), with decay governed by cavity expansion. Building on Hill's framework, we develop a model incorporating cavity volume and fracture toughness criteria, validated against PBX explosive (95% HMX-based) experiments. The model demonstrates improved prediction of pressure trends compared to prior approaches, particularly in resolving laminar-phase accumulation and crack-induced surge transitions. Results establish structural cavity volume as a critical modulator of measured pressure and reveal direction-dependent crack kinematics as fundamental features of constrained combustion. This work provides experimentally validated insights into mechanisms of reaction pressure development and burning cracks pathways during constrained PBX explosive combustion.
{"title":"Three-dimensional burning crack dynamics in constrained spherical explosive: visualization analysis and cavity-coupled pressure modeling","authors":"Chuanyu Pan, Tao Li, Hua Fu, Hailin Shang, Pingchao Hu, Ping Li, Xilong Huang","doi":"10.1016/j.dt.2025.06.011","DOIUrl":"10.1016/j.dt.2025.06.011","url":null,"abstract":"<div><div>Accurate characterization of three-dimensional burning crack propagation remains pivotal yet challenging for energetic material safety, as conventional diagnostics and models inadequately resolve coupled crack-pressure dynamics in confined explosives. This study combines a novel spherical confinement system (with/without sapphire windows) with synchronized high-speed imaging and 3D reconstruction to overcome optical limitations in opaque explosives. Experimental analysis of centrally ignited HMX-based PBX-1 reveals: (1) burning cracks propagate radially with equatorial acceleration and polar deceleration, (2) systematic formation of 3–4 dominant crack branches across geometries, and (3) pressure evolution exhibiting gradual accumulation (subsurface cracking) followed by exponential growth (surface burn-through), with decay governed by cavity expansion. Building on Hill's framework, we develop a model incorporating cavity volume and fracture toughness criteria, validated against PBX explosive (95% HMX-based) experiments. The model demonstrates improved prediction of pressure trends compared to prior approaches, particularly in resolving laminar-phase accumulation and crack-induced surge transitions. Results establish structural cavity volume as a critical modulator of measured pressure and reveal direction-dependent crack kinematics as fundamental features of constrained combustion. This work provides experimentally validated insights into mechanisms of reaction pressure development and burning cracks pathways during constrained PBX explosive combustion.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 306-318"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277814","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.03.022
Abbas Abbaspour, Behnoud Ganjavi, Mahdi Nematzadeh
Many researchers have focused on the behavior of fiber-reinforced concrete (FRC) in the construction of various defensive structures to resist against impact forces resulting from explosions and projectiles. However, the lack of sufficient research regarding the resistance of functionally graded fiber-reinforced concrete against projectile impacts has resulted in a limited understanding of the performance of this concrete type, which is necessary for the design and construction of structures requiring great resistance against external threats. Here, the performance of functionally graded fiber-reinforced concrete against projectile impacts was investigated experimentally using a (two-stage light) gas gun and a drop weight testing machine. For this objective, 12 mix designs, with which 35 cylindrical specimens and 30 slab specimens were made, were prepared, and the main variables were the magnetite aggregate vol% (55%) replacing natural coarse aggregate, steel fiber vol%, and steel fiber type (3D and 5D). The fibers were added at six vol% of 0%, 0.5%, 0.75%, 1%, 1.25%, and 1.5% in 10 specimen series (three identical specimens per each series) with dimensions of 40 × 40 × 7.5 cm and functional grading (three layers), and the manufactured specimens were subjected to the drop weight impact and projectile penetration tests by the drop weight testing machine and gas gun, respectively, to assess their performance. Parameters under study included the compressive strength, destruction level, and penetration depth. The experimental results demonstrate that using the magnetite aggregate instead of the natural coarse aggregate elevated the compressive strength of the concrete by 61%. In the tests by the drop weight machine, it was observed that by increasing the total vol% of the fibers, especially by increasing the fiber content in the outer layers (impact surface), the cracking resistance and energy absorption increased by around 100%. Note that the fiber geometry had little effect on the energy absorption in the drop weight test. Investigating the optimum specimens showed that using 3D steel fibers at a total fiber content of 1 vol%, consisting of a layered grading of 1.5 vol%, 0 vol%, and 1.5 vol%, improved the penetration depth by 76% and lowered the destruction level by 85%. In addition, incorporating the 5D steel fibers at a total fiber content of 1 vol%, consisting of the layered fiber contents of 1.5%, 0%, and 1.5%, improved the projectile penetration depth by 50% and lowered the damage level by 61% compared with the case of using the 3D fibers.
{"title":"Projectile impact and drop weight resistance of functionally graded fiber-reinforced magnetite aggregate concrete","authors":"Abbas Abbaspour, Behnoud Ganjavi, Mahdi Nematzadeh","doi":"10.1016/j.dt.2025.03.022","DOIUrl":"10.1016/j.dt.2025.03.022","url":null,"abstract":"<div><div>Many researchers have focused on the behavior of fiber-reinforced concrete (FRC) in the construction of various defensive structures to resist against impact forces resulting from explosions and projectiles. However, the lack of sufficient research regarding the resistance of functionally graded fiber-reinforced concrete against projectile impacts has resulted in a limited understanding of the performance of this concrete type, which is necessary for the design and construction of structures requiring great resistance against external threats. Here, the performance of functionally graded fiber-reinforced concrete against projectile impacts was investigated experimentally using a (two-stage light) gas gun and a drop weight testing machine. For this objective, 12 mix designs, with which 35 cylindrical specimens and 30 slab specimens were made, were prepared, and the main variables were the magnetite aggregate vol% (55%) replacing natural coarse aggregate, steel fiber vol%, and steel fiber type (3D and 5D). The fibers were added at six vol% of 0%, 0.5%, 0.75%, 1%, 1.25%, and 1.5% in 10 specimen series (three identical specimens per each series) with dimensions of 40 × 40 × 7.5 cm and functional grading (three layers), and the manufactured specimens were subjected to the drop weight impact and projectile penetration tests by the drop weight testing machine and gas gun, respectively, to assess their performance. Parameters under study included the compressive strength, destruction level, and penetration depth. The experimental results demonstrate that using the magnetite aggregate instead of the natural coarse aggregate elevated the compressive strength of the concrete by 61%. In the tests by the drop weight machine, it was observed that by increasing the total vol% of the fibers, especially by increasing the fiber content in the outer layers (impact surface), the cracking resistance and energy absorption increased by around 100%. Note that the fiber geometry had little effect on the energy absorption in the drop weight test. Investigating the optimum specimens showed that using 3D steel fibers at a total fiber content of 1 vol%, consisting of a layered grading of 1.5 vol%, 0 vol%, and 1.5 vol%, improved the penetration depth by 76% and lowered the destruction level by 85%. In addition, incorporating the 5D steel fibers at a total fiber content of 1 vol%, consisting of the layered fiber contents of 1.5%, 0%, and 1.5%, improved the projectile penetration depth by 50% and lowered the damage level by 61% compared with the case of using the 3D fibers.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 1-23"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277874","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.06.017
Yi Ren , Yu Nie , Bowen Xue , Yucheng Zhao , Lulu Liu , Chao Lou , Yongxun Li , Wei Chen
The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance. In this study, three novel lattice structures were developed by modifying the conventional FBCCZ unit cell through reversing, combining, and turning strategies. The designed lattices were fabricated via laser powder bed fusion (LPBF) using Ti-6Al-4V powder, and the mechanical properties, energy absorption capacity, and deformation behaviors were systematically investigated through quasi-static compression tests and finite element simulations. The results demonstrate that the three modified lattices exhibit superior performance over the conventional FBCCZ structure in terms of fracture strain, specific yield strength, specific ultimate strength, specific energy absorption, and energy absorption efficiency, thereby validating the efficacy of unit cell modifications in enhancing lattice performance. Notably, the CFBCCZ and TFBCCZ lattices significantly outperform both the FBCCZ and RFBCCZ lattice structures in load-bearing and energy absorption. While TFBCCZ shows marginally higher specific elastic modulus and energy absorption efficiency than CFBCCZ, the latter achieves superior energy absorption due to its highest ultimate strength and densification strain. Finite element simulations further reveal that the modified lattices, through optimized redistribution and adjustment of internal nodes and struts, effectively alleviate stress concentration during loading. This structural modification enhances the structural integrity and deformation stability under external loads, enabling a synergistic enhancement of load-bearing capacity and energy absorption performance.
{"title":"Synergistic enhancement of load-bearing and energy-absorbing performance in additively manufactured lattice structures through modifications to conventional unit cells","authors":"Yi Ren , Yu Nie , Bowen Xue , Yucheng Zhao , Lulu Liu , Chao Lou , Yongxun Li , Wei Chen","doi":"10.1016/j.dt.2025.06.017","DOIUrl":"10.1016/j.dt.2025.06.017","url":null,"abstract":"<div><div>The unit cell configuration of lattice structures critically influences their load-bearing and energy absorption performance. In this study, three novel lattice structures were developed by modifying the conventional FBCCZ unit cell through reversing, combining, and turning strategies. The designed lattices were fabricated via laser powder bed fusion (LPBF) using Ti-6Al-4V powder, and the mechanical properties, energy absorption capacity, and deformation behaviors were systematically investigated through quasi-static compression tests and finite element simulations. The results demonstrate that the three modified lattices exhibit superior performance over the conventional FBCCZ structure in terms of fracture strain, specific yield strength, specific ultimate strength, specific energy absorption, and energy absorption efficiency, thereby validating the efficacy of unit cell modifications in enhancing lattice performance. Notably, the CFBCCZ and TFBCCZ lattices significantly outperform both the FBCCZ and RFBCCZ lattice structures in load-bearing and energy absorption. While TFBCCZ shows marginally higher specific elastic modulus and energy absorption efficiency than CFBCCZ, the latter achieves superior energy absorption due to its highest ultimate strength and densification strain. Finite element simulations further reveal that the modified lattices, through optimized redistribution and adjustment of internal nodes and struts, effectively alleviate stress concentration during loading. This structural modification enhances the structural integrity and deformation stability under external loads, enabling a synergistic enhancement of load-bearing capacity and energy absorption performance.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 116-130"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145278359","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.05.024
Bojun Tan , Xiong Yang , Jinkang Dou , Jian Su , Jing Zhang , Siwei Song , Changwei Tang , Minghui Xu , Shu Zeng , Wenjie Li , Jieyu Luan , Gen Zhang , Qinghua Zhang , Xianming Lu , Bozhou Wang , Ning Liu
The simultaneous integration of high energy density, low sensitivity, and thermal stability in energetic materials has constituted a century-long scientific challenge. Herein, we address this through a dual-zwitterionic electronic delocalization strategy, yielding TYX-3, the first bis-inner salt triazolo-tetrazine framework combining these mutually exclusive properties. Uniform π-electron distribution and elevated bond dissociation energy confer exceptional thermal stability (Td = 365 °C) with TATB-level insensitivity (impact sensitivity IS > 40 J, friction sensitivity FS > 360 N). Engineered π-stacked networks enable record density (1.99 g·cm−3) with detonation performance surpassing HMX benchmarks (detonation velocity 9315 m·s−1, detonation pressure 36.6 GPa). Practical implementation in Poly (3-nitratomethyl-3-methyloxetane) (PNMMFO) solid propellants demonstrates 5.4-fold safety enhancement over conventional HMX-based formulations while maintaining equivalent specific impulse. This work establishes a new design paradigm for energetic materials, overcoming the historical trade-offs between molecular stability and energy output through rational zwitterionic engineering.
{"title":"Unprecedented energetic zwitterion integrating thermal stability, high energy density and low sensitivity: Overcoming performance trade-offs in conventional energetic materials","authors":"Bojun Tan , Xiong Yang , Jinkang Dou , Jian Su , Jing Zhang , Siwei Song , Changwei Tang , Minghui Xu , Shu Zeng , Wenjie Li , Jieyu Luan , Gen Zhang , Qinghua Zhang , Xianming Lu , Bozhou Wang , Ning Liu","doi":"10.1016/j.dt.2025.05.024","DOIUrl":"10.1016/j.dt.2025.05.024","url":null,"abstract":"<div><div>The simultaneous integration of high energy density, low sensitivity, and thermal stability in energetic materials has constituted a century-long scientific challenge. Herein, we address this through a dual-zwitterionic electronic delocalization strategy, yielding TYX-3, the first bis-inner salt triazolo-tetrazine framework combining these mutually exclusive properties. Uniform π-electron distribution and elevated bond dissociation energy confer exceptional thermal stability (<em>T</em><sub>d</sub> = 365 °C) with TATB-level insensitivity (impact sensitivity IS > 40 J, friction sensitivity FS > 360 N). Engineered π-stacked networks enable record density (1.99 g·cm<sup>−3</sup>) with detonation performance surpassing HMX benchmarks (detonation velocity 9315 m·s<sup>−1</sup>, detonation pressure 36.6 GPa). Practical implementation in Poly (3-nitratomethyl-3-methyloxetane) (PNMMFO) solid propellants demonstrates 5.4-fold safety enhancement over conventional HMX-based formulations while maintaining equivalent specific impulse. This work establishes a new design paradigm for energetic materials, overcoming the historical trade-offs between molecular stability and energy output through rational zwitterionic engineering.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 220-229"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145278361","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.06.002
Hua Fang , Xiaodong Liu , Hao Li , Junying Li , Jiajie Song , Fanzhi Yang , Ruibin Liu , Min Xia , Zhaobo Zhang , Yunjun Luo
The desensitization of nitramine explosives while maintaining energetic performance is challenging. A highly efficient desensitizer is the key to solving the antinomy. This study focuses on using porous organic cages (POCs), specifically CC3 and RCC3, to desensitize RDX. By coating 0.1 wt%–5 wt% of POCs on RDX particles, a series of composite energetic materials were prepared. Characterization results show that POCs change the surface morphology of RDX, and there are interfacial interactions between them. The RDX@POCs composites exhibit enhanced stabilities in terms of heat, impact, friction, and electrostatic spark. For the RDX@RCC3-5% composite, the impact sensitivity (EIS), friction sensitivity (EFS), and electrostatic sensitivity (EES) were significantly reduced by 66.7%, 68.8%, and 56.5%, respectively, while the detonation velocity decreased by merely 3.1%. These findings indicate that POCs, especially RCC3, are promising desensitizers for nitramine explosives, and their desensitization mechanisms likely involve barrier and buffering effects. The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.
{"title":"The application of porous organic cage as highly efficient desensitizer of RDX","authors":"Hua Fang , Xiaodong Liu , Hao Li , Junying Li , Jiajie Song , Fanzhi Yang , Ruibin Liu , Min Xia , Zhaobo Zhang , Yunjun Luo","doi":"10.1016/j.dt.2025.06.002","DOIUrl":"10.1016/j.dt.2025.06.002","url":null,"abstract":"<div><div>The desensitization of nitramine explosives while maintaining energetic performance is challenging. A highly efficient desensitizer is the key to solving the antinomy. This study focuses on using porous organic cages (POCs), specifically CC3 and RCC3, to desensitize RDX. By coating 0.1 wt%–5 wt% of POCs on RDX particles, a series of composite energetic materials were prepared. Characterization results show that POCs change the surface morphology of RDX, and there are interfacial interactions between them. The RDX@POCs composites exhibit enhanced stabilities in terms of heat, impact, friction, and electrostatic spark. For the RDX@RCC3-5% composite, the impact sensitivity (<em>E</em><sub>IS</sub>), friction sensitivity (<em>E</em><sub>FS</sub>), and electrostatic sensitivity (<em>E</em><sub>ES</sub>) were significantly reduced by 66.7%, 68.8%, and 56.5%, respectively, while the detonation velocity decreased by merely 3.1%. These findings indicate that POCs, especially RCC3, are promising desensitizers for nitramine explosives, and their desensitization mechanisms likely involve barrier and buffering effects. The distinct desensitization behavior of RDX@RCC3 highlights the effectiveness of POCs in reducing the sensitivity of RDX without significantly compromising its energetic properties.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 249-258"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145278363","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.06.004
Qinghua Hu , Chunxiang Xu , Wanpeng Li
The purpose of the covert communication scheme is to conceal the communication behavior entirely. In such schemes, the sender and receiver rely on secret keys to establish a covert channel. However, conventional key exchange protocols would expose the key exchange process between them. An adversary who observes the key exchange would be aware of the existence of communication behavior. The keys used in covert communication are not suitable to be generated through conventional key exchange schemes. To address this, we propose a blockchain-based covert elliptic-curve Diffie-Hellman key exchange scheme (BCDH) to conceal the process of the key exchange in blockchain transactions. Following a straightforward setup, BCDH allows the sender and receiver to covertly exchange a secret key on a blockchain without direct communication. Furthermore, we expand the BCDH approach to operate across multiple blockchains, further enhancing its covertness and stability. We analyze BCDH from several perspectives, including covertness, security, randomness, etc. Additionally, we implement a prototype of BCDH on the Ethereum platform to assess its feasibility and performance. Our evaluation demonstrates that BCDH is efficient and well-suited for real-world applications.
{"title":"BCDH: Blockchain-based covert Diffie-Hellman key exchange scheme","authors":"Qinghua Hu , Chunxiang Xu , Wanpeng Li","doi":"10.1016/j.dt.2025.06.004","DOIUrl":"10.1016/j.dt.2025.06.004","url":null,"abstract":"<div><div>The purpose of the covert communication scheme is to conceal the communication behavior entirely. In such schemes, the sender and receiver rely on secret keys to establish a covert channel. However, conventional key exchange protocols would expose the key exchange process between them. An adversary who observes the key exchange would be aware of the existence of communication behavior. The keys used in covert communication are not suitable to be generated through conventional key exchange schemes. To address this, we propose a blockchain-based covert elliptic-curve Diffie-Hellman key exchange scheme (BCDH) to conceal the process of the key exchange in blockchain transactions. Following a straightforward setup, BCDH allows the sender and receiver to covertly exchange a secret key on a blockchain without direct communication. Furthermore, we expand the BCDH approach to operate across multiple blockchains, further enhancing its covertness and stability. We analyze BCDH from several perspectives, including covertness, security, randomness, etc. Additionally, we implement a prototype of BCDH on the Ethereum platform to assess its feasibility and performance. Our evaluation demonstrates that BCDH is efficient and well-suited for real-world applications.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 24-31"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277875","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.05.023
Wenqing Li , Mianji Qiu , Wangjian Cheng , Qian Yang , Xiaohong Yan , Yousheng Qiu , Chongwei An , Baoyun Ye
The self-healing function is considered one of the effective ways to address structural damage and improve interfacial bonding in Energetic composite materials (ECMs). However, the currently prepared ECMs with self-healing function have problems such as irregular particle shape and uneven distribution of components, which affect the efficient play of self-healing function. In this paper, HMX-based energetic microspheres with self-healing function were successfully prepared by microchannel technology, which showed excellent self-healing effect in both Polymer-bonded explosives (PBXs) and Composite solid propellants (CSPs). The experimental results show that the HMX-based energetic microspheres with different binder contents prepared by microchannel technology show regular shape, HMX crystal particles are uniformly wrapped by self-healing binder (GAPU). When the content of GAPU in HMX-based energetic microspheres is 10%, PBXs show excellent self-healing effect and mechanical safety is improved by 400% (raw HMX vs S4, 5 J vs 25 J). As a high-energy component, the burning rate of CSPs is increased by 359.4%, the time (burning temperature > 1700 °C) is prolonged by 333.3%, and the maximum impulse force is increased by 107.3% (CSP-H vs CSP-S4, 0.84 mm/s vs 3.87 mm/s, 0.06 s vs 0.26 s, 0.82 mN vs 1.70 mN). It also has excellent storage performance. The preparation of HMX-based energetic microspheres with self-healing function by microchannel technology provides a new strategy to improve the storage performance of ECMs and the combustion performance of CSPs.
自愈功能被认为是解决高能复合材料（ecm）结构损伤和改善界面结合的有效途径之一。然而，目前制备的具有自愈功能的ecm存在颗粒形状不规则、组分分布不均匀等问题，影响了自愈功能的有效发挥。本文采用微通道技术成功制备了具有自修复功能的hmx基高能微球，该微球在聚合物粘结炸药（PBXs）和复合固体推进剂（csp）中均表现出优异的自修复效果。实验结果表明，采用微通道技术制备的不同粘结剂含量的HMX基含能微球呈规则形状，HMX晶体颗粒被自愈粘结剂（GAPU）均匀包裹。当GAPU在HMX基含能微球中的含量为10%时，pbx表现出良好的自愈效果，机械安全性提高400%（原料HMX vs S4, 5 J vs 25 J）。作为高能组分，csp的燃烧速度提高了359.4%，燃烧时间（燃烧温度>； 1700℃）延长了333.3%，最大冲力提高了107.3% （CSP-H vs CSP-S4, 0.84 mm/s vs 3.87 mm/s, 0.06 s vs 0.26 s, 0.82 mN vs 1.70 mN）。它还具有出色的存储性能。利用微通道技术制备具有自愈功能的hmx基能量微球，为提高ecm的储存性能和csp的燃烧性能提供了一种新的策略。
{"title":"Preparation of HMX-based energetic microspheres with efficient self-healing function by microchannel technology to enhance storage performance and interface bonding effect","authors":"Wenqing Li , Mianji Qiu , Wangjian Cheng , Qian Yang , Xiaohong Yan , Yousheng Qiu , Chongwei An , Baoyun Ye","doi":"10.1016/j.dt.2025.05.023","DOIUrl":"10.1016/j.dt.2025.05.023","url":null,"abstract":"<div><div>The self-healing function is considered one of the effective ways to address structural damage and improve interfacial bonding in Energetic composite materials (ECMs). However, the currently prepared ECMs with self-healing function have problems such as irregular particle shape and uneven distribution of components, which affect the efficient play of self-healing function. In this paper, HMX-based energetic microspheres with self-healing function were successfully prepared by microchannel technology, which showed excellent self-healing effect in both Polymer-bonded explosives (PBXs) and Composite solid propellants (CSPs). The experimental results show that the HMX-based energetic microspheres with different binder contents prepared by microchannel technology show regular shape, HMX crystal particles are uniformly wrapped by self-healing binder (GAPU). When the content of GAPU in HMX-based energetic microspheres is 10%, PBXs show excellent self-healing effect and mechanical safety is improved by 400% (raw HMX vs S4, 5 J vs 25 J). As a high-energy component, the burning rate of CSPs is increased by 359.4%, the time (burning temperature > 1700 °C) is prolonged by 333.3%, and the maximum impulse force is increased by 107.3% (CSP-H vs CSP-S4, 0.84 mm/s vs 3.87 mm/s, 0.06 s vs 0.26 s, 0.82 mN vs 1.70 mN). It also has excellent storage performance. The preparation of HMX-based energetic microspheres with self-healing function by microchannel technology provides a new strategy to improve the storage performance of ECMs and the combustion performance of CSPs.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 47-59"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277877","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}
Pub Date : 2025-10-01DOI: 10.1016/j.dt.2025.05.027
Siyi Zhang , Yue Jiang , Dunhui Xu , Jingxuan Li , Changlu Zhao , Lijun Yang
Boron-based fuels, recognized for their high energy density and potential in energetic applications, encounter challenges such as long ignition delays and incomplete combustion, which result in reduced combustion efficiency and limited performance in aerospace propulsion. In this study, boron carbide (B4C) is investigated as an alternative fuel to pristine boron due to its favorable gas-phase combustion. Both metal oxide (nickel oxide (NiO)) and metal fluoride (nickel fluoride (NiF2)) are selected as oxidizing modifiers to enhance the reactivity of B4C. A method combining laser ignition with optical diagnostics is employed to investigate the enhancing effects of different oxidizers on the ignition and combustion characteristics of B4C. Both NiO and NiF2 can significantly increase the combustion radiation intensity and reduce the time to maximum intensity of B4C. Differential scanning calorimetry, in-situ X-ray diffraction, and Fourier transform infrared spectroscopy were used for simultaneous thermal analysis of the B4C composite powders. Combined thermal analysis showed that the effects of NiO and NiF2 on promoting B4C combustion is mainly achieved via the formation of NimBn and the release of a large number of gas products. It is reasonable to speculate that the phase separation at the B2O3/NimBn interface forms new pathways for oxygen diffusion and reaction with the B core. The difference in the combustion mechanism of B4C with NiO and NiF2 lies in the gas phase products, i.e., CO2 and BF3, respectively, thus leading to significant differences in their reaction processes.
{"title":"Investigating the effect of NiO and NiF2 on boron carbide combustion","authors":"Siyi Zhang , Yue Jiang , Dunhui Xu , Jingxuan Li , Changlu Zhao , Lijun Yang","doi":"10.1016/j.dt.2025.05.027","DOIUrl":"10.1016/j.dt.2025.05.027","url":null,"abstract":"<div><div>Boron-based fuels, recognized for their high energy density and potential in energetic applications, encounter challenges such as long ignition delays and incomplete combustion, which result in reduced combustion efficiency and limited performance in aerospace propulsion. In this study, boron carbide (B<sub>4</sub>C) is investigated as an alternative fuel to pristine boron due to its favorable gas-phase combustion. Both metal oxide (nickel oxide (NiO)) and metal fluoride (nickel fluoride (NiF<sub>2</sub>)) are selected as oxidizing modifiers to enhance the reactivity of B<sub>4</sub>C. A method combining laser ignition with optical diagnostics is employed to investigate the enhancing effects of different oxidizers on the ignition and combustion characteristics of B<sub>4</sub>C. Both NiO and NiF<sub>2</sub> can significantly increase the combustion radiation intensity and reduce the time to maximum intensity of B<sub>4</sub>C. Differential scanning calorimetry, in-situ X-ray diffraction, and Fourier transform infrared spectroscopy were used for simultaneous thermal analysis of the B<sub>4</sub>C composite powders. Combined thermal analysis showed that the effects of NiO and NiF<sub>2</sub> on promoting B<sub>4</sub>C combustion is mainly achieved via the formation of Ni<sub><em>m</em></sub>B<sub><em>n</em></sub> and the release of a large number of gas products. It is reasonable to speculate that the phase separation at the B<sub>2</sub>O<sub>3</sub>/Ni<sub><em>m</em></sub>B<sub><em>n</em></sub> interface forms new pathways for oxygen diffusion and reaction with the B core. The difference in the combustion mechanism of B<sub>4</sub>C with NiO and NiF<sub>2</sub> lies in the gas phase products, i.e., CO<sub>2</sub> and BF<sub>3</sub>, respectively, thus leading to significant differences in their reaction processes.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"52 ","pages":"Pages 60-70"},"PeriodicalIF":5.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145277878","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}
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