Defence Technology(防务技术)最新文献

{"title":"Size-dependent heat conduction of thermal cellular structures: A surface-enriched multiscale method","authors":"Xiaofeng Xu ,&nbsp;Junfeng Li ,&nbsp;Xuanhao Wu ,&nbsp;Ling Ling ,&nbsp;Li Li","doi":"10.1016/j.dt.2025.02.002","DOIUrl":"10.1016/j.dt.2025.02.002","url":null,"abstract":"<div><div>This paper examined how microstructure influences the homogenized thermal conductivity of cellular structures and revealed a surface-induced size-dependent effect. This effect is linked to the porous microstructural features of cellular structures, which stems from the degree of porosity and the distribution of the pores. Unlike the phonon-driven surface effect at the nanoscale, the macro-scale surface mechanism in thermal cellular structures is found to be the microstructure-induced changes in the heat conduction path based on fully resolved 3D numerical simulations. The surface region is determined by the microstructure, characterized by the intrinsic length. With the coupling between extrinsic and intrinsic length scales under the surface mechanism, a surface-enriched multiscale method was developed to accurately capture the complex size-dependent thermal conductivity. The principle of scale separation required by classical multiscale methods is not necessary to be satisfied by the proposed multiscale method. The significant potential of the surface-enriched multiscale method was demonstrated through simulations of the effective thermal conductivity of a thin-walled metamaterial structure. The surface-enriched multiscale method offers higher accuracy compared with the classical multiscale method and superior efficiency over high-fidelity finite element methods.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"49 ","pages":"Pages 50-67"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144501668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the reaction kinetics mechanism and properties of RDX/ADN/FKM2602 composite microspheres","authors":"Cenlin Pan ,&nbsp;Zhenhua Liu ,&nbsp;Yubing Zhao ,&nbsp;Ning Liu ,&nbsp;Taixing Liang ,&nbsp;Xiaodong Li ,&nbsp;Jingyu Wang ,&nbsp;Xiaofeng Shi","doi":"10.1016/j.dt.2025.02.008","DOIUrl":"10.1016/j.dt.2025.02.008","url":null,"abstract":"<div><div>This study prepared a class of RDX-based composite microspheres (RAF) containing ADN and FKM2602. The reaction kinetics of RAF composite microspheres were effectively improved by maintaining the system's high energy and safety performance. In the close packing state, when the heating rate is rapid, the thermal stability of RAF composite microspheres is better than that of RDX; the close packing state will reduce the degree of freedom of RDX and ADN reaction but will increase the degree of freedom of RAF composite microsphere reaction. The thermal conductivity of RAF composite microspheres is close to that of RDX. In the ignition experiment, the flame of RAF composite microspheres can be maintained without the external heat source. Regarding safety, the <em>H</em>₅₀ of RAF composite microspheres was 274.04% higher than that of RDX. The detonation velocity of RAF composite microspheres is slightly higher than that of raw material RDX. Overall, these findings highlight the effectiveness of ADN in enhancing the reaction kinetics of RDX-based composites.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 131-140"},"PeriodicalIF":5.0,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139669","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":"Reliability analysis of modular charge swinging-loading positioning accuracy under new failure criterion based on spatial geometric relationship","authors":"Zihan Wang ,&nbsp;Linfang Qian ,&nbsp;Liu Yang ,&nbsp;Taisu Liu ,&nbsp;Weiwei Chen ,&nbsp;Haolin Zhang","doi":"10.1016/j.dt.2025.02.006","DOIUrl":"10.1016/j.dt.2025.02.006","url":null,"abstract":"<div><div>The swinging-loading process is essential for automatic artillery loading systems. This study focuses on the problems of reliability analysis that affect swinging-loading positioning accuracy. A dynamic model for a multi degree-of-freedom swinging-loading-integrated rigid–flexible coupling system is established. This model is based on the identification of key parameters and platform experiments. Based on the spatial geometric relationship between the breech and loader during modular charge transfer and the possible maximum interference depth of the modular charge, a new failure criterion for estimating the reliability of swinging-loading positioning accuracy is proposed. Considering the uncertainties in the operation of the pendulum loader, the direct probability integration method is introduced to analyze the reliability of the swinging-loading positioning accuracy under three different charge numbers. The results indicate that under two and four charges, the swinging-loading process shows outstanding reliability. However, an unstable stage appears when the swinging motion occurred under six charges, with a maximum positioning failure probability of 0.0712. A comparison between the results obtained under the conventional and proposed criteria further reveals the effectiveness and necessity of the proposed criterion.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 115-130"},"PeriodicalIF":5.0,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139668","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":"Situation maintenance-based cooperative guidance strategy for intercepting a superior target","authors":"Xinghui Yan ,&nbsp;Yuzhong Tang ,&nbsp;Heng Shi ,&nbsp;Yulei Xu ,&nbsp;Yiding Liu","doi":"10.1016/j.dt.2025.01.020","DOIUrl":"10.1016/j.dt.2025.01.020","url":null,"abstract":"<div><div>A situation maintenance-based cooperative guidance strategy is proposed to intercept a high-speed and high-maneuverability target via inferior missiles. Reachability and relative motion analyses are conducted to develop and pursue virtual targets, respectively. A two-stage guidance strategy under nonlinear kinematics is developed on the basis of virtual targets. The first stage optimizes the coverage and collision situation by pursuing virtual targets under specific angular constraints. The second stage subsequently intercepts the superior target based on the handover condition optimized by the first stage. Numerical simulation results are provided to compare the effectiveness and superiority of the proposed strategy with those of the reachability-based cooperative strategy (RCS), coverage-based cooperative guidance (CBCG) and augmented proportional navigation (APN) under various maneuvering modes.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 250-267"},"PeriodicalIF":5.0,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139080","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":"Surface-covering water significantly amplifies the explosion impulse of shallow buried explosives","authors":"Zhenyu Zhao ,&nbsp;Wenbo Gao ,&nbsp;Jianwei Ren ,&nbsp;Zihan Lan ,&nbsp;Zhiyang Zhang ,&nbsp;Huiyao Gao ,&nbsp;Chao He ,&nbsp;Changye Ni ,&nbsp;Tianjian Lu","doi":"10.1016/j.dt.2025.01.007","DOIUrl":"10.1016/j.dt.2025.01.007","url":null,"abstract":"<div><div>While the moisture content of soil affects significantly the blast impulse of shallow buried explosives, the role of surface-covering water (SCW) on soil in such blast impulse remains elusive. A combined experimental and numerical study has been carried out to characterize the effect of SCW on transferred impulse and loading magnitude of shallow buried explosives. Firstly, blast tests of shallow buried explosives were conducted, with and without the SCW, to quantitatively assess the blast loading impulse. Subsequently, finite element (FE) simulations were performed and validated against experimental measurement, with good agreement achieved. The validated FE model was then employed to predict the dynamic response of a fully-clamped metallic circular target, subjected to the explosive impact of shallow buried explosives with SCW, and explore the corresponding physical mechanisms. It was demonstrated that shallow buried explosives in saturated soil generate a greater impulse transferred towards the target relative to those in dry soil. The deformation displacement of the target plate is doubled. Increasing the height of SCW results in enhanced center peak deflection of the loaded target, accompanied by subsequent fall, due to the variation of deformation pattern of the loaded target from concentrated load to uniform load. Meanwhile, the presence of SCW increases the blast impulse transferred towards the target by three times. In addition, there exists a threshold value of the burial depth that maximizes the impact impulse. This threshold exhibits a strong sensitivity to SCW height, decreasing with increasing SCW height. An empirical formula for predicting threshold has been provided. Similar conclusions can be drawn for different explosive masses. The results provide technical guidance on blast loading intensity and its spatial distribution considering shallow buried explosives in coast-land battlefields, which can ultimately contribute to better protective designs.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 156-172"},"PeriodicalIF":5.0,"publicationDate":"2025-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144138418","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 detonation wave propagation and the calculation methods for shock wave overpressure distribution of composite charges","authors":"Jiaxin Yu,&nbsp;Weibing Li,&nbsp;Junbao Li,&nbsp;Xiaoming Wang,&nbsp;Wenbin Li","doi":"10.1016/j.dt.2025.01.017","DOIUrl":"10.1016/j.dt.2025.01.017","url":null,"abstract":"<div><div>To explore the design criteria for composite charges and reveal the intrinsic relationship between the detonation wave propagation in composite charges and the overall energy distribution of shock waves, this study analyzes the propagation and interaction processes of detonation waves in composite charges with different structural dimensions and explosive combinations. It also investigates the spatial distribution characteristics of the resulting shock wave loads. Based on dimensional analysis theory, a theoretical analysis of the shock wave overpressure distribution in free air fields is conducted. Utilizing the derived dimensionless function relationships, the hydrocode AUTODYN is employed to investigate the effects of charge structure parameters and explosive combinations on the internal overdriven detonation phenomena and the distribution of shock wave loads. It is found that the overdriven detonation phenomenon in the inner layer of composite charges increases the strength of the axial detonation wave, thereby enhancing the intensity of the primary end wave formed upon refraction into the air, which affects the distribution characteristics of the shock wave overpressure. Research has shown that increasing the thickness ratio and detonation velocity ratio of composite charges is beneficial for exacerbating the phenomenon of overdriven detonation, improving the primary end wave intensity and axial overpressure. This gain effect gradually weakens with the propagation of shock waves. When overdriven detonation occurs inside the composite charge, the detonation pressure first increases and then decreases. The Mach reflection pressure of the composite charge with a larger aspect ratio is attenuated to a greater extent. In addition, as the aspect ratio of the composite charge increases, the shock wave energy gradually flows from the axial direction to the radial direction. Therefore, as the aspect ratio of the composite charge increases, the primary end wave intensity and axial overpressure gradually decrease.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 204-220"},"PeriodicalIF":5.0,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139078","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":"Efficiently enhancing thermal conductivity of polymer bonded explosives via the construction of primary-secondary thermal conductivity networks","authors":"Xunyi Wang ,&nbsp;Peng Wang ,&nbsp;Jie Chen ,&nbsp;Zhipeng Liu ,&nbsp;Yuxin Luo ,&nbsp;Wenbin Yang ,&nbsp;Guansong He","doi":"10.1016/j.dt.2025.01.018","DOIUrl":"10.1016/j.dt.2025.01.018","url":null,"abstract":"<div><div>Realizing effective enhancement in the thermally conductive performance of polymer bonded explosives (PBXs) is vital for improving the resultant environmental adaptabilities of the PBXs composites. Herein, a kind of primary-secondary thermally conductive network was designed by water-suspension granulation, surface coating, and hot-pressing procedures in the graphene-based PBXs composites to greatly increase the thermal conductive performance of the composites. The primary network with a three-dimensional structure provided the heat-conducting skeleton, while the secondary network in the polymer matrix bridged the primary network to increase the network density. The enhancement efficiency in the thermally conductive performance of the composites reached the highest value of 59.70% at a primary-secondary network ratio of 3:1. Finite element analysis confirmed the synergistic enhancement effect of the primary and secondary thermally conductive networks. This study introduces an innovative approach to designing network structures for PBX composites, significantly enhancing their thermal conductivity.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"48 ","pages":"Pages 95-103"},"PeriodicalIF":5.0,"publicationDate":"2025-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144139667","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":"Ballistic response mechanism and resistance-driven evaluation method of UHMWPE composite","authors":"Yemao He ,&nbsp;Johnny Qing Zhou ,&nbsp;Yanan Jiao ,&nbsp;Hongshuai Lei ,&nbsp;Zeang Zhao ,&nbsp;Daining Fang","doi":"10.1016/j.dt.2024.06.007","DOIUrl":"10.1016/j.dt.2024.06.007","url":null,"abstract":"<div><div>The use of ultra-high molecular weight polyethylene (UHMWPE) composite in the design of lightweight protective equipment, has gained a lot of interest. However, there is an urgent need to understand the ballistic response mechanism and theoretical prediction model of performance. This paper explores the ballistic response mechanism of UHMWPE composite through experimental and simulation analyses. Then, a resistance-driven modeling method was proposed to establish a theoretical model for predicting the bulletproof performance. The ballistic response mechanism of UHMWPE composite encompassed three fundamental modes: local response, structural response, and coupled response. The occurrence ratio of these fundamental response modes during impact was dependent on the projectile velocity and laminate thickness. The bulletproof performance of laminate under different response modes was assessed based on the penetration depth of the projectile, the bulging height on the rear face of the laminate, the thickness of remaining sub-laminate, and residual velocity of the projectile. The absolute deviations of bulletproof performance indicator between theoretical value and experimental value were well within 11.13%, demonstrating that the established evaluation model possessed high degree of prediction accuracy.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"44 ","pages":"Pages 1-16"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141408691","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":"An efficient and accurate numerical method for simulating close-range blast loads of cylindrical charges based on neural network","authors":"Ting Liu ,&nbsp;Changhai Chen ,&nbsp;Han Li ,&nbsp;Yaowen Yu ,&nbsp;Yuansheng Cheng","doi":"10.1016/j.dt.2024.10.001","DOIUrl":"10.1016/j.dt.2024.10.001","url":null,"abstract":"<div><div>To address the problems of low accuracy by the CONWEP model and poor efficiency by the Coupled Eulerian-Lagrangian (CEL) method in predicting close-range air blast loads of cylindrical charges, a neural network-based simulation (NNS) method with higher accuracy and better efficiency was proposed. The NNS method consisted of three main steps. First, the parameters of blast loads, including the peak pressures and impulses of cylindrical charges with different aspect ratios (<em>L</em>/<em>D</em>) at different stand-off distances and incident angles were obtained by two-dimensional numerical simulations. Subsequently, incident shape factors of cylindrical charges with arbitrary aspect ratios were predicted by a neural network. Finally, reflected shape factors were derived and implemented into the subroutine of the ABAQUS code to modify the CONWEP model, including modifications of impulse and overpressure. The reliability of the proposed NNS method was verified by related experimental results. Remarkable accuracy improvement was acquired by the proposed NNS method compared with the unmodified CONWEP model. Moreover, huge efficiency superiority was obtained by the proposed NNS method compared with the CEL method. The proposed NNS method showed good accuracy when the scaled distance was greater than 0.2 m/kg^1/3. It should be noted that there is no need to generate a new dataset again since the blast loads satisfy the similarity law, and the proposed NNS method can be directly used to simulate the blast loads generated by different cylindrical charges. The proposed NNS method with high efficiency and accuracy can be used as an effective method to analyze the dynamic response of structures under blast loads, and it has significant application prospects in designing protective structures.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"44 ","pages":"Pages 257-271"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436886","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":"HTEC foot: A novel foot structure for humanoid robots combining static stability and dynamic adaptability","authors":"Jintao Zhang ,&nbsp;Xuechao Chen ,&nbsp;Zhangguo Yu ,&nbsp;Lianqiang Han ,&nbsp;Zhifa Gao ,&nbsp;Qingrui Zhao ,&nbsp;Gao Huang ,&nbsp;Ke Li ,&nbsp;Qiang Huang","doi":"10.1016/j.dt.2024.08.010","DOIUrl":"10.1016/j.dt.2024.08.010","url":null,"abstract":"<div><div>Passive bionic feet, known for their human-like compliance, have garnered attention for their potential to achieve notable environmental adaptability. In this paper, a method was proposed to unifying passive bionic feet static supporting stability and dynamic terrain adaptability through the utilization of the Rigid-Elastic Hybrid (REH) dynamics model. First, a bionic foot model, named the Hinge Tension Elastic Complex (HTEC) model, was developed by extracting key features from human feet. Furthermore, the kinematics and REH dynamics of the HTEC model were established. Based on the foot dynamics, a nonlinear optimization method for stiffness matching (NOSM) was designed. Finally, the HTEC-based foot was constructed and applied onto BHR-B2 humanoid robot. The foot static stability is achieved. The enhanced adaptability is observed as the robot traverses square steel, lawn, and cobblestone terrains. Through proposed design method and structure, the mobility of the humanoid robot is improved.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"44 ","pages":"Pages 30-51"},"PeriodicalIF":5.0,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143436946","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}