Defence Technology(防务技术)最新文献_第7页

Experimental and numerical approach of afterburning effects in fuel-rich explosives within confined spaces 富燃料炸药在密闭空间内加力效应的实验与数值研究

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.009

Hu Zhou , Ange Lu , Cheng Zheng , Yiwen Wang , Xiangshao Kong , Weiguo Wu

The detonation of fuel-rich explosives yields combustible products that persistently burn upon mixing with ambient oxygen, releasing additional energy through a phenomenon known as the afterburning effect. This process greatly influences the evolution of confined blast loading and the subsequent structural response, which is crucial in confined blast scenarios. Given the complex nature of the reaction process, accurate analysis of the afterburning effect remains challenging. Previous studies have either overlooked the mechanisms of detonation product combustion or failed to provide experimental validation. This study introduces a three-dimensional model to effectively characterize the combustion of detonation products. The model integrates chemical reaction source terms into the governing equations to consider the combustion processes. Numerical simulations and experimental tests were conducted to analyze the combustion and energy release from the detonation products of fuel-rich explosives in confined spaces. Approximately 50% of the energy was released during the combustion of detonation products in a confined TNT explosion. Although the combustion of these products was much slower than the detonation process, it aligned with the dynamic response of the structure, which enhanced the explosive yield. Excluding afterburning from the analysis reduced the center-point deformation of the structure by 30%. Following the inclusion of afterburning, the simulated quasi-static pressure increased by approximately 45%. Subsequent comparisons highlighted the merits of the proposed approach over conventional methods. This approach eliminates the reliance on empirical parameters, such as the amount and rate of energy release during afterburning, thereby laying the foundation for understanding load evolution in more complex environments, such as ships, buildings, and underground tunnels.

富燃料炸药的爆炸产生可燃产物，这些可燃产物与周围的氧气混合后持续燃烧，通过一种称为加力燃烧效应的现象释放出额外的能量。这一过程极大地影响了约束爆炸荷载的演变和随后的结构响应，这在约束爆炸场景中是至关重要的。鉴于反应过程的复杂性，对加力效应的准确分析仍然具有挑战性。以往的研究要么忽视了爆轰产物燃烧的机理，要么未能提供实验验证。本研究引入三维模型来有效表征爆轰产物的燃烧。该模型将化学反应源项集成到控制方程中以考虑燃烧过程。通过数值模拟和试验分析了富燃料炸药在密闭空间内的燃烧和爆轰产物的能量释放。在密闭TNT爆炸中，大约50%的能量是在爆轰产物燃烧过程中释放的。虽然这些产物的燃烧比爆轰过程慢得多，但与结构的动态响应一致，从而提高了爆炸当量。在分析中排除加力燃烧后，结构的中心点变形减少了30%。加入加力燃烧后，模拟准静压提高了约45%。随后的比较突出了所提出的方法优于传统方法的优点。这种方法消除了对经验参数的依赖，如加力燃烧过程中能量释放的数量和速率，从而为理解更复杂环境（如船舶、建筑物和地下隧道）中的载荷演变奠定了基础。

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引用次数: 0

Linear WDE for performance enhancement of MIMO-OFDM system in the presence of Co-CFO 在Co-CFO存在下用于MIMO-OFDM系统性能增强的线性WDE

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.011

Khaled Ramadan , Emad S. Hassan

The Discrete Walsh Hadamard Transform (DWHT) has emerged as an efficient alternative to the Discrete Fourier Transform (DFT) for Orthogonal Frequency Division Multiplexing (OFDM) implementations, particularly in handling channel impairments. In this article, we proposed an efficient Joint Low Complexity Regularized Zero Forcing-Wavelet Domain Equalizer (JLCRLZF-WDE) to replace the traditional Frequency Domain Equalizer (FDE) in DWHT-OFDM systems. Unlike FDE, which requires additional DFT and Inverse DFT (IDFT) computations, the proposed JLCRLZF-WDE directly operates in the Walsh domain, effectively mitigating the computational overhead. The derivation of the proposed JLCRLZF-WDE equations take the effect of the channel, Co-Carrier Frequency Offset (Co-CFO), as well as the noise into account. During the derivation of the system model equations, we assume a Multiple-Input-Multiple-Output (MIMO)-OFDM communication system through a Rayleigh fading channel. The Bit Error Rate (BER) performance and computational complexity of the proposed and the conventional algorithms are compared, indicating the significance of the proposed algorithm. Simulation results confirm the superiority of the proposed equalizer, demonstrating a 23.68%–28.4% reduction in computational complexity compared to Minimum Mean Square Error (LMMSE)-FDE based on DFT, while maintaining comparable BER performance at various MIMO configuration. Furthermore, at a BER of 10⁻⁴, the JLCRLZF-WDE achieves performance parity with conventional Walsh domain LMMSE equalizers, whereas other equalizers require an additional Signal-to-Noise Ratio (SNR) of 3.06 dB to achieve the same performance.

离散Walsh Hadamard变换（DWHT）已成为正交频分复用（OFDM）实现中离散傅立叶变换（DFT）的有效替代方案，特别是在处理信道损伤方面。本文提出了一种高效的联合低复杂度正则化零强制-小波域均衡器（JLCRLZF-WDE）来取代DWHT-OFDM系统中传统的频域均衡器（FDE）。与FDE需要额外的DFT和逆DFT （IDFT）计算不同，JLCRLZF-WDE直接在Walsh域中操作，有效地减少了计算开销。所提出的JLCRLZF-WDE方程的推导考虑了信道、共载波频率偏移（Co-CFO）以及噪声的影响。在推导系统模型方程的过程中，我们假设一个通过瑞利衰落信道的多输入多输出(MIMO)-OFDM通信系统。比较了该算法与传统算法的误码率性能和计算复杂度，说明了该算法的重要意义。仿真结果证实了所提出的均衡器的优越性，与基于DFT的最小均方误差(LMMSE)-FDE相比，计算复杂度降低了23.68%-28.4%，同时在各种MIMO配置下保持了相当的误码性能。此外，在10−4的误码率下，JLCRLZF-WDE实现了与传统Walsh域LMMSE均衡器相同的性能，而其他均衡器需要额外的信噪比（SNR）为3.06 dB才能实现相同的性能。

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引用次数: 0

Multi-scale impact resistance of flexible microporous metal rubber: Dynamic energy dissipation mechanism based on dynamic friction locking effect 柔性微孔金属橡胶的多尺度抗冲击性能：基于动态摩擦锁紧效应的动态能量耗散机理

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.013

Qiang Song , Liangliang Shen , Linwei Shi , Ling Pan , Ang Wang , Zhiying Ren

Flexible microporous metal rubber (FMP-MR) is widely used in national defense applications, yet its mechanical behavior under high-speed impact conditions remains insufficiently explored. In this study, dynamic and static experiments were conducted to systematically investigate the mechanical response of metal-wrapped microporous materials under impact loading that spanned 10⁶ orders of magnitude. By combining a high-precision numerical model with a spatial contact point search algorithm, the spatio–temporal contact characteristics of the complex network structure in FMP-MR were systematically analyzed. Furthermore, the mapping mechanism from turn topology and mesoscopic friction behavior to macroscopic mechanical properties was comprehensively explored. The results showed that compared with quasi-static loading, FMP-MR under high-speed impact exhibited higher energy absorption efficiency due to high-strain-rate inertia effect. Therefore, the peak stress increased by 141%, and the maximum energy dissipation increased by 300%. Consequently, the theory of dynamic friction locking effect was innovatively proposed. The theory explains that the close synergistic effect of sliding friction and plastic dissipation promoted by the stable interturn-locked embedded structure is the essential reason for the excellent dynamic mechanical properties of FMP-MR under dynamic loading conditions. Briefly, based on the in-depth investigation of the mechanical response and energy dissipation mechanism of FMP-MR under impact loads, this study provides a solid theoretical basis for further expanding the application range of FMP-MR and optimizing its performance.

柔性微孔金属橡胶（FMP-MR）广泛应用于国防领域，但其在高速冲击条件下的力学性能研究尚不充分。本研究通过动态和静态实验，系统研究了金属包覆微孔材料在106个数量级的冲击载荷下的力学响应。采用高精度数值模型和空间接触点搜索算法相结合的方法，系统分析了FMP-MR复杂网络结构的时空接触特征。在此基础上，全面探讨了从匝拓扑和细观摩擦行为到宏观力学性能的映射机理。结果表明：与准静态载荷相比，FMP-MR在高速冲击下由于高应变率惯性效应，具有更高的能量吸收效率；因此，峰值应力增加了141%，最大能量耗散增加了300%。创新性地提出了动态摩擦锁紧效应理论。理论解释了稳定的互锁嵌固结构促进滑动摩擦和塑性耗散的密切协同效应是FMP-MR在动载条件下具有优异动态力学性能的根本原因。简而言之，本研究在深入研究FMP-MR在冲击载荷作用下的力学响应和耗能机理的基础上，为进一步扩大FMP-MR的应用范围和优化其性能提供了坚实的理论基础。

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引用次数: 0

Corrosion-assisted fatigue crack growth behaviour of AA 7075-T651 friction stir welded joints: Influence of extended seawater exposure on microstructure and fracture characteristics AA 7075-T651搅拌摩擦焊接接头腐蚀辅助疲劳裂纹扩展行为：长时间海水暴露对显微组织和断裂特征的影响

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.04.021

Karthick Ganesan , S.R. Koteswara Rao , T. Srinivasa Rao , V. Rohit

This study investigates the corrosion-assisted fatigue crack growth rate (FCGR) of 16 mm thick AA 7075-T651 friction stir welded (FSW) joints. Compact tension (CT) specimens were extracted from both the base material and FSW joints to evaluate FCGR under varying corrosion exposure durations (0, 7, 30, 60, and 90 days) at a constant stress ratio of 0.5. Microstructural analysis of the welds was conducted using optical and transmission electron microscopy (TEM). Results indicate that the critical stress intensity factor range (ΔK_cr) of FSW joints is lower than that of the base material, primarily due to precipitate dissolution in the weld zone during the FSW process, as confirmed by TEM analysis. The fatigue life of FSW joints was significantly lower than that of the base material, but with prolonged exposure to seawater corrosion, the gap in fatigue life narrowed. Specimens exposed to seawater for more than 60 days exhibited minimal differences in fatigue life between the base material and the FSW joints. This was attributed to the higher corrosion rate of the base material compared to the weld nugget, resulting in the formation of deeper pits that facilitated crack initiation and accelerated fatigue failure. The findings conclude that extended corrosion exposure leads to similar fatigue life and crack growth behaviour in both the base material and FSW joints. SEM and EDX analysis of AA7075-T651 revealed corrosion pits and rust products in initiation zones, ductile striations in growth regions, and secondary cracks with micro voids in fracture zones. FSW joints exhibited ultra-fine grains, smooth ductile fracture in initiation and growth regions, and brittle fracture in the fracture zones under both corroded and uncorroded conditions.

研究了16mm厚AA 7075-T651搅拌摩擦焊（FSW）接头的腐蚀辅助疲劳裂纹扩展速率（FCGR）。在恒定应力比为0.5的条件下，从基材和FSW接头中提取致密拉伸（CT）试样，以评估不同腐蚀暴露时间（0、7、30、60和90天）下的FCGR。利用光学显微镜和透射电镜对焊缝进行了显微组织分析。结果表明：瞬变TEM分析证实，FSW接头的临界应力强度因子范围（ΔKcr）低于母材，这主要是由于FSW焊接过程中焊缝区析出物溶解所致。FSW接头的疲劳寿命明显低于母材，但随着海水腐蚀时间的延长，疲劳寿命的差距逐渐缩小。暴露在海水中超过60天的试样显示，基材和FSW接头之间的疲劳寿命差异很小。这是由于与焊核相比，基材的腐蚀速度更快，导致形成更深的凹坑，从而促进裂纹的形成，加速疲劳失效。研究结果表明，延长腐蚀暴露时间会导致基材和FSW接头的疲劳寿命和裂纹扩展行为相似。SEM和EDX分析表明，AA7075-T651在起裂区存在腐蚀坑和锈蚀产物，在生长区存在延性条纹，在断口区存在带微孔洞的次生裂纹。在腐蚀和未腐蚀条件下，FSW接头在萌生区和生长区均表现为超细晶粒、光滑韧性断裂，在断口区表现为脆性断裂。

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引用次数: 0

Effect of post weld heat treatment on grain boundary character distribution and corrosion resistance of friction stir welded armour-grade nickel and molybdenum-free high-nitrogen austenitic stainless steel 焊后热处理对搅拌摩擦焊接装甲级无镍钼高氮奥氏体不锈钢晶界特征、分布及耐蚀性的影响

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.016

Arun Kumar Gurrala , Raffi Mohammed , G Madhusudhan Reddy

This study examines the effects of friction stir welding (FSW) and post-weld heat treatment (PWHT) on the grain boundary character distribution and corrosion resistance of cross sectional (top and bottom) regions of nickel-and molybdenum-free high-nitrogen austenitic stainless steel (HNASS).FSW at 400 rpm and 30 mm/min resulted in finer grains (4.18 μm) and higher coincident site lattice (CSL) boundaries (32.3%) at the top of the stir zone (SZ) due to dynamic recrystallization (DRX). PWHT at 900 °C for 1 h led to grain coarsening (12.91μm the bottom SZ) but enhanced CSL boundaries from 24.6% to 30.2%, improving grain boundary stability. PWHT reduced the kernel average misorientation (KAM) by 14.9% in the SZ-top layer and 20.4% in the SZ-bottom layer, accompanied by a 25% decrease in hardness in the SZ-top layer and 26.7% in the SZ-bottom layer, indicating strain recovery and reduced dislocation density. Potentiodynamic polarization tests (PDP) showed a 18% increase in pitting potential and a 76% reduction in corrosion rate after PWHT. The improvement in corrosion resistance is attributed to the increase in Σ3 twin boundaries, which enhance grain boundary stability and reduce susceptibility to localized corrosion. These findings highlight the role of PWHT in refining the microstructure and strengthening corrosion resistance, making HNASS a promising material for demanding applications.

本文研究了搅拌摩擦焊（FSW）和焊后热处理（PWHT）对无镍、无钼高氮奥氏体不锈钢（HNASS）横截面（顶部和底部）晶界特征、分布和耐蚀性的影响。在400 rpm和30 mm/min转速下，由于动态再结晶（DRX），搅拌区（SZ）顶部的晶粒更细（4.18 μm），重合点位晶格（CSL）边界更高（32.3%）。900℃PWHT 1 h使晶粒粗化（下SZ为12.91μm），但使CSL晶界从24.6%提高到30.2%，提高了晶界稳定性。PWHT使SZ-top层和SZ-bottom层的核平均位错（KAM）分别降低了14.9%和20.4%，SZ-top层和SZ-bottom层的硬度分别降低了25%和26.7%，表明应变恢复和位错密度降低。动电位极化测试（PDP）表明，PWHT后，点蚀电位增加18%，腐蚀速率降低76%。耐蚀性能的提高主要是由于Σ3孪晶界的增加，增强了晶界的稳定性，降低了局部腐蚀的敏感性。这些发现突出了PWHT在细化微观结构和增强耐腐蚀性方面的作用，使HNASS成为一种有前景的材料。

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引用次数: 0

Sustainable large-format additive manufacturing of composite molds with 45-degree deposition strategies 45度沉积策略复合材料模具的可持续大尺寸增材制造

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.014

Pablo Castelló-Pedrero , Javier Bas-Bolufer , César García-Gascón , Juan Antonio García-Manrique , Francisco Chinesta

Military missions in hostile environments are often costly and unpredictable, with squadrons sometimes facing isolation and resource scarcity. In such scenarios, critical components in vehicles, drones, and energy generators may require structural reinforcement or repair due to damage. This paper proposes a portable, on-site production method for molds under challenging conditions, where material supply is limited. The method utilizes large format additive manufacturing (LFAM) with recycled composite materials, sourced from end-of-life components and waste, as feedstock. The study investigates the microstructural effects of recycling through shredding techniques, using microscopic imaging. Three potential defense-sector applications are explored, specifically in the aerospace, automotive, and energy industries. Additionally, the influence of key printing parameters, particularly non-parallel plane deposition at a 45-degree angle, on the mechanical behavior of ABS reinforced with 20% glass fiber (GF) is examined. The results demonstrate the feasibility of this manufacturing approach, highlighting reductions in waste material and production times compared to traditional methods. Shorter layer times were found to reduce thermal gradients between layers, thereby improving layer adhesion. While 45-degree deposition enhanced Young's modulus, it slightly reduced interlayer adhesion quality. Furthermore, recycling-induced fiber length reduction led to material degradation, aligning with findings from previous studies. Challenges encountered during implementation included weak part adherence to the print bed and local excess material deposition. Overall, the proposed methodology offers a cost-effective alternative to traditional CNC machining for mold production, demonstrating its potential for on-demand manufacturing in resource-constrained environments.

在敌对环境中执行军事任务往往成本高昂且难以预测，中队有时会面临孤立和资源短缺。在这种情况下，车辆、无人机和能源发电机中的关键部件可能需要结构加固或修理。本文提出了一种便携式，现场生产方法的模具在具有挑战性的条件下，其中材料供应有限。该方法利用大幅面增材制造（LFAM）和回收的复合材料，从报废部件和废物中采购，作为原料。该研究调查了微观结构的影响，通过粉碎技术，利用显微成像回收。探索了三种潜在的国防部门应用，特别是在航空航天，汽车和能源工业。此外，还研究了关键打印参数，特别是45度角非平行平面沉积对20%玻璃纤维增强ABS力学性能的影响。结果证明了这种制造方法的可行性，与传统方法相比，突出了废料和生产时间的减少。发现较短的层时间可以减少层之间的热梯度，从而改善层的附着力。45度沉积提高了杨氏模量，但略微降低了层间粘附质量。此外，回收引起的纤维长度减少导致材料降解，这与先前的研究结果一致。在实施过程中遇到的挑战包括打印床的零件粘附性差和局部过量材料沉积。总体而言，所提出的方法为模具生产提供了一种具有成本效益的传统CNC加工替代方案，展示了其在资源受限环境下按需制造的潜力。

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引用次数: 0

Development and experimental validation of the dynamic constitutive model and equation of state for Mo-10Cu alloy Mo-10Cu合金动态本构模型和状态方程的建立与实验验证

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.018

Bihui Hong, Wenbin Li, Yiming Li, Weihang Li, Peng Chen, Yalong Wang

This study systematically investigates the mechanical response characteristics of Mo-10Cu pseudo-alloy under various conditions, including temperatures ranging from 298 K to 550 K, strain rates from 1 × 10⁻² s⁻¹ to 5.2 × 10³ s⁻¹, and dynamic impact loads from 134 m/s to 837 m/s. The investigation is conducted using a combination of multi-method crossover experiment and numerical simulations, with accuracy validated through X-ray testing and static penetration test. Using a universal testing machine, Split-Hopkinson Pressure Bar (SHPB) system, and a light-gas gun, the dynamic constitutive behavior and shock adiabatic curves of the alloy under complex loading conditions are revealed. Experimental results demonstrate that the flow stress evolution of Mo-10Cu alloy exhibits significant strain hardening, and strain-rate strengthening. Based on these observations, a Johnson-Cook (J-C) constitutive model has been developed to describe the material's dynamic behavior. Through free-surface particle velocity measurements, the shock adiabatic relationship was obtained, and a Gruneisen equation of state was established. X-ray experimental results confirm that the Mo-10Cu liner can generate well-formed, cohesive jets. The penetration test results show that the maximum penetration depth can reach 243.10 mm. The maximum error between the numerical simulation and the X-ray test is less than 7.70%, and the error with the penetration test is 4.73%, which confirms the accuracy of the constitutive parameters and the state equation. In conclusion, the proposed J-C model and Gruneisen equation effectively predict the dynamic response and jet formation characteristics of Mo-10Cu alloy under extreme loads. This work provides both theoretical support and experimental data for material design and performance optimization in shaped charge applications.

本文系统研究了Mo-10Cu伪合金在298 ~ 550 K温度、1 × 10−2 s−1 ~ 5.2 × 103 s−1应变速率和134 ~ 837 m/s动态冲击载荷下的力学响应特性。研究采用多方法交叉实验和数值模拟相结合的方法进行，并通过x射线测试和静态穿透测试验证了准确性。利用万能试验机、Split-Hopkinson压杆（SHPB）系统和光气枪，研究了复合加载条件下合金的动态本构行为和冲击绝热曲线。实验结果表明，Mo-10Cu合金流变应力演化表现出明显的应变硬化和应变速率强化。基于这些观察，Johnson-Cook （J-C）本构模型已经被开发用来描述材料的动态行为。通过对自由表面粒子速度的测量，得到了激波绝热关系，建立了Gruneisen状态方程。x射线实验结果证实，Mo-10Cu衬里可以产生形状良好的内聚射流。侵彻试验结果表明，最大侵彻深度可达243.10 mm。数值模拟与x射线试验的最大误差小于7.70%，与侵彻试验的最大误差为4.73%，验证了本构参数和状态方程的准确性。综上所述，J-C模型和Gruneisen方程能够有效预测Mo-10Cu合金在极端载荷下的动态响应和射流形成特性。这项工作为聚能装药的材料设计和性能优化提供了理论支持和实验数据。

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引用次数: 0

Failure modes and transformation laws of reinforced concrete slabs under drop hammer impact 落锤作用下钢筋混凝土板的破坏模式及变形规律

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.010

Chunming Song , Jiahe Zhong , Haotian Zhang , Yuetang Zhao , Zhongwei Zhang , Feng Liu

With the change of the main influencing factors such as structural configuration and impact conditions, reinforced concrete slabs exhibit different mechanical behaviors with different failure patterns, and the failure modes are transformed. In order to reveal the failure mode and transformation rule of reinforced concrete slabs under impact loads, a dynamic impact response test was carried out using a drop hammer test device. The dynamic data pertaining to the impact force, support reaction force, structural displacement, and reinforcement strain were obtained through the use of digital image correlation technology (DIC), impact force measurement, and strain measurement. The analysis of the ultimate damage state of the reinforced concrete slab identified four distinct types of impact failure modes: local failure by stamping, overall failure by stamping, local-overall coupling failure, and local failure by punching. Additionally, the influence laws of hammerhead shape, hammer height, and reinforcement ratio on the dynamic response and failure mode transformation of the slab were revealed. The results indicate that: (1) The local damage to the slab by the plane hammer is readily apparent, while the overall damage by the spherical hammer is more pronounced. (2) In comparison to the high reinforcement ratio slabs, the overall bending resistance of the low reinforcement ratio slabs is significantly inferior, and the slab back exhibits further cracks. (3) As the hammer height increases, the slab failure mode undergoes a transformation, shifting from local failure by stamping and overall failure by stamping to local-overall coupling failure and local failure by punching. (4) Three failure mode thresholds have been established, and by comparing the peak impact force with the failure thresholds, the failure mode of the slab can be effectively determined.

随着结构形态和冲击条件等主要影响因素的改变，钢筋混凝土板在不同的破坏模式下表现出不同的力学行为，并发生破坏模式的转换。为了揭示钢筋混凝土板在冲击荷载作用下的破坏模式和转变规律，采用落锤试验装置进行了钢筋混凝土板的动态冲击响应试验。通过数字图像相关技术（DIC）、冲击力测量和应变测量，获得了结构的冲击力、支撑反力、结构位移和钢筋应变等动态数据。通过对钢筋混凝土板的极限破坏状态分析，确定了四种不同类型的冲击破坏模式：局部冲压破坏、整体冲压破坏、局部-整体耦合破坏和局部冲压破坏。揭示了锤头形状、锤头高度和配筋率对板坯动力响应和破坏模式转变的影响规律。结果表明：(1)平面锤对板坯的局部损伤较为明显，而球锤对板坯的整体损伤更为明显。(2)与高配筋板相比，低配筋板的整体抗弯能力明显差于高配筋板，板背进一步出现裂缝。(3)随着锤头高度的增加，板坯破坏模式发生转变，由局部冲压破坏和整体冲压破坏转变为局部-整体耦合破坏和局部冲孔破坏。(4)建立了3个破坏模式阈值，通过将峰值冲击力与破坏阈值进行比较，可以有效确定板坯的破坏模式。

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引用次数: 0

Purification of amorphous boron powder through the removal of impurity magnesium and its physicochemical properties 通过去除杂质镁提纯无定形硼粉及其理化性质

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.004

Shuxuan Lv , Zhen Cao , Jijun Wu

At present, the most common preparation method of amorphous boron powder is magnesium thermal reduction method, but the amorphous boron powder obtained by this method mostly contains impurities such as magnesium and oxygen which are difficult to remove, and these impurities will seriously affect the application of amorphous boron powder and need to be strictly removed. In this research, the acid-insoluble impurities were modified through sintering and quenching, while the magnesium impurities were optimized via ultrasonic acid leaching. We observed that the quenching temperature played a crucial role in determining the efficiency of magnesium impurity removal. The results show that the magnesium content in amorphous boron powder can be reduced from 5.67% to 2.40% by quenching the amorphous boron powder at 800 °C and using ultrasonic assisted acid leaching. Furthermore, the oxidation reaction of boron is influenced by the powder's particle size and specific surface area, with the effective activation energy being intimately tied to both these factors. Post-quenching and acid leaching, we observed an increase in the specific surface area of the boron powder samples, leading to enhanced activity. In conclusion, our study presents an effective strategy to mitigate magnesium impurities and elevate the performance of amorphous boron powder, offering promising avenues for advancing its utilization across diverse industries.

目前最常用的非晶态硼粉制备方法是镁热还原法，但这种方法得到的非晶态硼粉大多含有镁、氧等难以去除的杂质，这些杂质会严重影响非晶态硼粉的应用，需要严格去除。在本研究中，通过烧结和淬火对酸不溶性杂质进行改性，通过超声波酸浸对镁杂质进行优化。我们观察到淬火温度对镁杂质的去除效率起着至关重要的作用。结果表明：将非晶硼粉在800℃下淬火并采用超声辅助酸浸，可使非晶硼粉中的镁含量从5.67%降至2.40%；此外，硼的氧化反应受粉末粒度和比表面积的影响，有效活化能与这两个因素密切相关。淬火和酸浸后，我们观察到硼粉样品的比表面积增加，导致活性增强。总之，我们的研究提出了一种有效的策略来减少镁杂质和提高非晶硼粉的性能，为促进其在不同行业的应用提供了有希望的途径。

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引用次数: 0

Enhancing bonding reliability of solid propellant grain based on FFTA and PSO-GRNN 基于FFTA和PSO-GRNN的固体推进剂颗粒键合可靠性提高

IF 5.9 Q1 ENGINEERING, MULTIDISCIPLINARY

Defence Technology(防务技术)

Pub Date : 2025-09-01 DOI: 10.1016/j.dt.2025.05.007

Han Lu , Bin Zhang , Wei Xu , Zhigang Xu , Xinlin Bai , Zheng Hu

Bonding quality at the interface of solid propellant grains is crucial for the reliability and safety of solid rocket motors. Although bonding reliability is influenced by numerous factors, the lack of quantitative characterization of interface debonding mechanisms and the challenge of identifying key factors have made precise control of process variables difficult, resulting in unpredictable failure risks. This paper presents an improved fuzzy failure probability evaluation method that combines fuzzy fault tree analysis with expert knowledge, transforming process data into fuzzy failure probability to accurately assess debonding probabilities. The predictive model is constructed through a general regression neural network and optimized using the particle swarm optimization algorithm. Sensitivity analysis is conducted to identify key decision variables, including normal force, grain rotation speed, and adhesive weight, which are verified experimentally. Compared with classical models, the maximum error margin of the constructed reliability prediction model is only 0.02%, and it has high stability. The experimental results indicate that the main factors affecting debonding are processing roughness and coating uniformity. Controlling the key decision variable as the median resulted in a maximum increase of 200.7% in bonding strength. The feasibility of the improved method has been verified, confirming that identifying key decision variables has the ability to improve bonding reliability. The proposed method simplifies the evaluation of propellant interface bonding reliability under complex conditions by quantifying the relationship between process parameters and failure risk, enabling targeted management of key decision variables.

固体推进剂颗粒界面的粘结质量对固体火箭发动机的可靠性和安全性至关重要。虽然粘接可靠性受到许多因素的影响，但由于缺乏对界面脱粘机理的定量表征，以及确定关键因素的挑战，使得对工艺变量的精确控制变得困难，从而导致不可预测的失效风险。本文提出了一种改进的模糊故障概率评估方法，将模糊故障树分析与专家知识相结合，将过程数据转化为模糊故障概率，以准确评估脱粘概率。通过广义回归神经网络构建预测模型，并采用粒子群优化算法进行优化。通过灵敏度分析，确定了法向力、颗粒转速、黏着量等关键决策变量，并进行了实验验证。与经典模型相比，所构建的可靠性预测模型的最大误差仅为0.02%，具有较高的稳定性。实验结果表明，影响剥离的主要因素是加工粗糙度和涂层均匀性。控制关键决策变量为中位数，最大可提高200.7%的结合强度。验证了改进方法的可行性，证实了识别关键决策变量具有提高粘接可靠性的能力。该方法通过量化工艺参数与失效风险之间的关系，简化了复杂条件下推进剂界面结合可靠性的评估，实现了关键决策变量的针对性管理。

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引用次数: 0