Defence Technology(防务技术)最新文献_第2页

Characterization of combined blast- and fragments-induced synergetic damage in polyurea coated liquid-filled container 聚脲涂层充液容器中爆炸和碎片共同诱发的协同损伤的特征

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.009

Chen Tao , Chong Ji , Xin Wang , Juan Gu , Yuting Wang , Changxiao Zhao

Liquid-filled containers (LFC) are widely used to store and transport petroleum, chemical reagents, and other resources. As an important target of military strikes and terrorist bombings, LFC are vulnerable to blast waves and fragments. To explore the protective effect of polyurea elastomer on LFC, the damage characteristics of polyurea coated liquid-filled container (PLFC) under the combined loading of blast shock wave and fragments were studied experimentally. The microstructure of the polyurea layer was observed by scanning electron microscopy, and the fracture and self-healing phenomena were analyzed. The simulation approach was used to explain the combined blast- and fragments-induced on the PLFC in detail. Finally, the effects of shock wave and fragment alone and in combination on the damage of PLFC were comprehensively compared. Results showed that the polyurea reduces the perforation rate of the fragment to the LFC, and the self-healing phenomenon could also reduce the liquid loss rate inside the container. The polyurea reduces the degree of depression in the center of the LFC, resulting in a decrease in the distance between adjacent fragments penetrating the LFC, and an increase in the probability of transfixion and fracture between holes. Under the close-in blast, the detonation shock wave reached the LFC before the fragment. Polyurea does not all have an enhanced effect on the protection of LFC. The presence of internal water enhances the anti-blast performance of the container, and the hydrodynamic ram (HRAM) formed by the fragment impacting the water aggravated the plastic deformation of the container. The combined action has an enhancement effect on the deformation of the LFC. The depth of the container depression was 27% higher than that of the blast shock wave alone; thus, it cannot be simply summarized as linear superposition.

充液容器 (LFC) 广泛用于储存和运输石油、化学试剂和其他资源。作为军事打击和恐怖爆炸的重要目标，充液容器很容易受到爆炸波和碎片的伤害。为了探索聚脲弹性体对充液容器的保护作用，实验研究了聚脲涂层充液容器（PLFC）在爆炸冲击波和碎片共同作用下的损伤特征。通过扫描电子显微镜观察了聚脲层的微观结构，分析了聚脲层的断裂和自修复现象。采用模拟方法详细解释了冲击波和碎片对聚脲层的综合影响。最后，综合比较了冲击波和碎片单独及组合对 PLFC 损伤的影响。结果表明，聚脲降低了碎片对 LFC 的穿孔率，自愈现象也降低了容器内的液体流失率。聚脲降低了 LFC 中心的凹陷程度，导致相邻碎片穿透 LFC 的距离减小，孔与孔之间的吸附和断裂概率增加。在近距离爆炸下，爆炸冲击波先于碎片到达 LFC。聚脲并非对 LFC 的保护都有增强作用。内部水的存在增强了容器的抗爆性能，碎片撞击水形成的水动力冲撞（HRAM）加剧了容器的塑性变形。这两种作用对 LFC 的变形有增强作用。集装箱的凹陷深度比单独的爆炸冲击波高出 27%，因此不能简单地将其概括为线性叠加。

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引用次数: 0

Current development and future prospects of multi-target assignment problem: A bibliometric analysis review

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.09.006

Shuangxi Liu , Zehuai Lin , Wei Huang , Binbin Yan

The multi-target assignment (MTA) problem, a crucial challenge in command control, mission planning, and a fundamental research focus in military operations, has garnered significant attention over the years. Extensively studied across various domains such as land, sea, air, space, and electronics, the MTA problem has led to the emergence of numerous models and algorithms. To delve deeper into this field, this paper starts by conducting a bibliometric analysis on 463 Scopus database papers using CiteSpace software. The analysis includes examining keyword clustering, co-occurrence, and burst, with visual representations of the results. Following this, the paper provides an overview of current classification and modeling techniques for addressing the MTA problem, distinguishing between static multi-target assignment (SMTA) and dynamic multi-target assignment (DMTA). Subsequently, existing solution algorithms for the MTA problem are reviewed, generally falling into three categories: exact algorithms, heuristic algorithms, and machine learning algorithms. Finally, a development framework is proposed based on the "HIGH" model (high-speed, integrated, great, harmonious) to guide future research and intelligent weapon system development concerning the MTA problem. This framework emphasizes application scenarios, modeling mechanisms, solution algorithms, and system efficiency to offer a roadmap for future exploration in this area.

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引用次数: 0

The impact of the coupling relationship between projectile size and yarn dimension on the ballistic performance of plain weave fabric

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.06.016

Kaiying Wang , Xuan Zhou , Wenke Ren , Yiding Wu , Yilei Yu , Yi Zhou , Lizhi Xu , Guangfa Gao

Aramid fibers, due to their relatively high inter-yarn friction, high strength, high modulus, and other characteristics, have become a typical representative of flexible anti-ballistic materials in modern warfare. Current research on the anti-penetration of aramid fabrics mostly focuses unilaterally on the structure and performance of aramid fabrics or the shape and size of projectiles, with fewer studies on the coupled effect of both on ballistic performance. This study analyzes how the coupling relationship (or size effect) between the projectile and fiber bundle dimensions affects the fabric ballistic performance from a mesoscopic scale perspective. Taking plain weave aramid fabric as the research object, considering different diameter projectiles, through a large number of ballistic impact tests and numerical simulations, parameters such as ballistic limit velocity, average energy absorption of fabric, and specific energy absorption ratio (average energy absorption of fabric divided by projectile cross-sectional area) are obtained for ballistic performance analysis. The influence law of projectile size on the ballistic performance of high-performance fabrics is as follows: The relative range of fitted ballistic limit velocity at different target positions gradually decreases and then stabilizes as the projectile diameter increases, indicating that the fabric structure effect gradually disappears at a projectile diameter of 12 mm; The average ballistic limit velocity at three impact positions, P1, P2, and P3, provides the corresponding ballistic limit velocity for 1000D aramid fabric, which increases with projectile diameter but the rate of increase slows down at an inflection point, which in this study occurs where the fabric structure effect nearly disappears at a projectile diameter of 12 mm; The energy absorption ratio increases and then decreases as the projectile diameter increases from 4 mm to 20 mm, reaching a peak at the diameter of 12 mm due to the gradual disappearance of the fabric structural effect. The projectile diameter of 12 mm corresponds to the coupling size of 11.159, which provides a size design reference for the macroscopic-based continuum models of aramid plain weave fabrics.

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引用次数: 0

Data driven prediction of fragment velocity distribution under explosive loading conditions 爆炸加载条件下碎片速度分布的数据驱动预测

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.07.007

Donghwan Noh , Piemaan Fazily , Songwon Seo , Jaekun Lee , Seungjae Seo , Hoon Huh , Jeong Whan Yoon

This study presents a machine learning-based method for predicting fragment velocity distribution in warhead fragmentation under explosive loading condition. The fragment resultant velocities are correlated with key design parameters including casing dimensions and detonation positions. The paper details the finite element analysis for fragmentation, the characterizations of the dynamic hardening and fracture models, the generation of comprehensive datasets, and the training of the ANN model. The results show the influence of casing dimensions on fragment velocity distributions, with the tendencies indicating increased resultant velocity with reduced thickness, increased length and diameter. The model's predictive capability is demonstrated through the accurate predictions for both training and testing datasets, showing its potential for the real-time prediction of fragmentation performance.

引用次数: 0

FedCLCC: A personalized federated learning algorithm for edge cloud collaboration based on contrastive learning and conditional computing FedCLCC：基于对比学习和条件计算的边缘云协作个性化联合学习算法

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.08.015

Kangning Yin , Xinhui Ji , Yan Wang , Zhiguo Wang

Federated learning (FL) is a distributed machine learning paradigm for edge cloud computing. FL can facilitate data-driven decision-making in tactical scenarios, effectively addressing both data volume and infrastructure challenges in edge environments. However, the diversity of clients in edge cloud computing presents significant challenges for FL. Personalized federated learning (pFL) received considerable attention in recent years. One example of pFL involves exploiting the global and local information in the local model. Current pFL algorithms experience limitations such as slow convergence speed, catastrophic forgetting, and poor performance in complex tasks, which still have significant shortcomings compared to the centralized learning. To achieve high pFL performance, we propose FedCLCC: Federated Contrastive Learning and Conditional Computing. The core of FedCLCC is the use of contrastive learning and conditional computing. Contrastive learning determines the feature representation similarity to adjust the local model. Conditional computing separates the global and local information and feeds it to their corresponding heads for global and local handling. Our comprehensive experiments demonstrate that FedCLCC outperforms other state-of-the-art FL algorithms.

联合学习（FL）是一种适用于边缘云计算的分布式机器学习范例。FL 可以促进战术场景中的数据驱动决策，有效解决边缘环境中的数据量和基础设施挑战。然而，边缘云计算中客户端的多样性给联合学习带来了巨大挑战。近年来，个性化联合学习（pFL）受到了广泛关注。个性化联合学习的一个例子是利用本地模型中的全局和局部信息。目前的 pFL 算法存在收敛速度慢、灾难性遗忘、在复杂任务中表现不佳等局限性，与集中式学习相比仍有明显不足。为了实现较高的 pFL 性能，我们提出了 FedCLCC：Federated Contrastive Learning and Conditional Computing（联邦对比学习和条件计算）。FedCLCC 的核心是使用对比学习和条件计算。对比学习确定特征表示的相似性，从而调整局部模型。条件计算将全局和局部信息分离开来，并将其反馈到相应的头部进行全局和局部处理。我们的综合实验证明，FedCLCC 优于其他最先进的 FL 算法。

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引用次数: 0

Taming of trinitromethyl-oxadiazole to access high density and high oxygen balance via a dual modulation strategy 通过双重调制策略驯服三硝基甲基恶二唑，实现高密度和高氧平衡

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.07.003

Jinya Zhang , Teng Fei , Jingwei Meng , Jinxiong Cai , Lei Zhang , Siping Pang , Chunlin He

Energetic compounds bearing the trinitromethyl group are garnering broad attraction as potential candidates for a new generation of high energy dense oxidizers. In this work, an effective dual modulation strategy involving both molecular isomerization and crystal morphology control was employed to design and optimize trinitromethyl-oxadiazole with improved comprehensive performance. Utilizing this dual strategy, 3,5-bis(trinitromethyl)-1,2,4-oxadiazole (3) was synthesized, resulting in the formation of two distinct crystal morphologies (needle and sheet) corresponding to two crystal forms (3-a and 3-b). Encouragingly, while maintaining ultra-high oxygen balance (21.73%), 3 achieves impressive densities (1.97–1.98 g/cm³). To our knowledge, the density of 1.98 g/cm³ for 3-a sets a new record among that of nitrogen-rich monocyclic compounds. Notably, practical crystal morphology prediction was creatively introduced to guide the experimental crystallization conditions of 3, increasing the impact sensitivity and friction sensitivity from 1 J to 80 N (3-a) to 10 J and 240 N (3-b), respectively. Additionally, the crystal structural analyses and theoretical calculations were conducted to elucidate the reasons of differences between 3-a and 3-b in density and stability. This work provides an efficient strategy to enhance performance of trinitromethyl derivatives, broadening the path and expanding the toolbox for energetic materials.

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引用次数: 0

Honeycomb-spiderweb-inspired self-similar hybrid cellular structures for impact applications 用于冲击应用的蜂巢-蜘蛛网启发自相似混合蜂窝结构

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.06.015

K. Tewari, M.K. Pandit, M.M. Mahapatra, P.R. Budarapu

Inspired by nature's self-similar designs, novel honeycomb-spiderweb based self-similar hybrid cellular structures are proposed here for efficient energy absorption in impact applications. The energy absorption is enhanced by optimizing the geometry and topology for a given mass. The proposed hybrid cellular structure is arrived after a thorough analysis of topologically enhanced self-similar structures. The optimized cell designs are rigorously tested considering dynamic loads involving crush and high-velocity bullet impact. Furthermore, the influence of thickness, radial connectivity, and order of patterning at the unit cell level are also investigated. The maximum crushing efficiency attained is found to be more than 95%, which is significantly higher than most existing traditional designs. Later on, the first and second-order hierarchical self-similar unit cell designs developed during crush analysis are used to prepare the cores for sandwich structures. Impact tests are performed on the developed sandwich structures using the standard 9-mm parabellum. The influence of multistaging on impact resistance is also investigated by maintaining a constant total thickness and mass of the sandwich structure. Moreover, in order to avoid layer-wise weak zones and hence, attain a uniform out-of-plane impact strength, off-setting the designs in each stage is proposed. The sandwich structures with first and second-order self-similar hybrid cores are observed to withstand impact velocities as high as 170 m/s and 270 m/s, respectively.

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引用次数: 0

Dynamic properties of low-density expandable polystyrene concrete materials 低密度可膨胀聚苯乙烯混凝土材料的动态特性

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.07.006

Jue Han , Hualin Fan

Expanded polystyrene (EPS) concrete, known for its environmental friendliness, energy absorption capacity, and low impedance, has significant potential application in the fields of wave absorption and vibration reduction. This study designed and prepared EPS concrete materials with four levels of density. Quasi-static uniaxial compression and Split Hopkinson Pressure Bar (SHPB) impact tests were conducted to obtain stress-strain curves, elastic moduli, failure modes, energy absorptions, and strain rate effects of the EPS concrete under quasi-static and dynamic loading conditions. The influences of density on various performance indicators were analyzed. By combining the Zhu-Wang-Tang (ZWT) constitutive model with a modified elastic-brittle model, a modified dynamic constitutive model was proposed. The accuracy of the model was validated by the experimental data. The results indicate that the addition of EPS particles enhances the ductility of the EPS concrete. The EPS concrete has significant strain rate effect, which gets stronger as density increases. The modifiedconstitutive model accurately characterizes the dynamic stress-strain curves of the EPS concrete.

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引用次数: 0

Autonomous sortie scheduling for carrier aircraft fleet under towing mode 拖曳模式下航母舰队的自主出动调度

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.07.011

Zhilong Deng , Xuanbo Liu , Yuqi Dou , Xichao Su , Haixu Li , Lei Wang , Xinwei Wang

Safe and efficient sortie scheduling on the confined flight deck is crucial for maintaining high combat effectiveness of the aircraft carrier. The primary difficulty exactly lies in the spatiotemporal coordination, i.e., allocation of limited supporting resources and collision-avoidance between heterogeneous dispatch entities. In this paper, the problem is investigated in the perspective of hybrid flow-shop scheduling problem by synthesizing the precedence, space and resource constraints. Specifically, eight processing procedures are abstracted, where tractors, preparing spots, catapults, and launching are virtualized as machines. By analyzing the constraints in sortie scheduling, a mixed-integer planning model is constructed. In particular, the constraint on preparing spot occupancy is improved to further enhance the sortie efficiency. The basic trajectory library for each dispatch entity is generated and a delayed strategy is integrated to address the collision-avoidance issue. To efficiently solve the formulated HFSP, which is essentially a combinatorial problem with tightly coupled constraints, a chaos-initialized genetic algorithm is developed. The solution framework is validated by the simulation environment referring to the Fort-class carrier, exhibiting higher sortie efficiency when compared to existing strategies. And animation of the simulation results is available at www.bilibili.com/video/BV14t421A7Tt/. The study presents a promising supporting technique for autonomous flight deck operation in the foreseeable future, and can be easily extended to other supporting scenarios, e.g., ammunition delivery and aircraft maintenance.

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引用次数: 0

Research on the hazards of gas leakage and explosion in a full-scale residential building 关于大型住宅楼燃气泄漏和爆炸危害的研究

IF 5 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-01-01 DOI: 10.1016/j.dt.2024.06.014

Chengjun Yue, Li Chen, Zhan Li, Bin Feng, Ruizhi Xu

The gas explosion in residential building has always been a highly concerned problem. Explosions in homogeneous mixtures have been extensively studied. However, mixtures are often inhomogeneous in the practical scenarios due to the differences in the densities of methane and air. In order to investigate the effects of gas explosions in inhomogeneous mixtures, experimental studies involving gas leakage and explosion are conducted in a full-scale residential building to reproduce the process of gas explosion. By fitting the dimensionless buoyancy as a function of dimensionless height and dimensionless time, a distribution model of gas in large-scale spaces is established, and the mechanism of inhomogeneous distribution of methane is also be revealed. Furthermore, the stratified reconstruction method (SRM) is introduced for efficiently setting up inhomogeneous concentration fields in FLACS. The simulation results highlight that for the internal overpressure, the distribution of methane has no effect on the first overpressure peak (ΔP1), while it significantly influences the subsequent overpressure peak (ΔP2), and the maximum difference between the overpressure of homogeneous and inhomogeneous distribution is 174.3%. Moreover, the initial concentration distribution also has a certain impact on the external overpressure.

住宅楼内的气体爆炸一直是一个备受关注的问题。人们对均质混合物中的爆炸进行了广泛的研究。然而，在实际应用中，由于甲烷和空气的密度不同，混合物往往是不均匀的。为了研究非均质混合物中气体爆炸的影响，我们在一座全尺寸住宅楼中进行了涉及气体泄漏和爆炸的实验研究，以重现气体爆炸的过程。通过拟合无量纲浮力作为无量纲高度和无量纲时间的函数，建立了气体在大尺度空间中的分布模型，并揭示了甲烷非均质分布的机理。此外，还引入了分层重构法（SRM），以便在 FLACS 中有效地建立非均质浓度场。模拟结果表明，对于内部超压，甲烷分布对第一个超压峰值（ΔP1）没有影响，而对随后的超压峰值（ΔP2）有显著影响，均质分布和非均质分布的超压最大差值为 174.3%。此外，初始浓度分布也对外部超压有一定影响。

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引用次数: 0