Pub Date : 2026-01-01DOI: 10.1016/j.dt.2025.05.012
Peng Li , Ruibo Li , Zijiao Fan , Jiujiu Han , Guangda Ding , Qunbiao Wang , Wanye Xu , Paolo Rocca
In this study, the design, analysis, manufacturing, and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented. 3D printing technology is used to fabricate a curved ceramic substrate, and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate. The problems of gain loss, bandwidth reduction, and frequency shift caused by high temperatures are addressed by using a proper antenna design, with parasitic patches, slots, and metal resonant cavities. The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers, the patch, and the ground plane; its performance is examined up to a temperature of 600 °C in a muffle furnace and compared with the results from the numerical analysis. The results show that the antenna can effectively function at 600 °C and even higher temperatures.
{"title":"3D printed high-temperature ceramic conformal array antenna: Design, analysis, manufacturing, and testing","authors":"Peng Li , Ruibo Li , Zijiao Fan , Jiujiu Han , Guangda Ding , Qunbiao Wang , Wanye Xu , Paolo Rocca","doi":"10.1016/j.dt.2025.05.012","DOIUrl":"10.1016/j.dt.2025.05.012","url":null,"abstract":"<div><div>In this study, the design, analysis, manufacturing, and testing of a 3D-printed conformal microstrip array antenna for high-temperature environments is presented. 3D printing technology is used to fabricate a curved ceramic substrate, and laser sintering and microdroplet spraying processes are used to add the conductive metal on the curved substrate. The problems of gain loss, bandwidth reduction, and frequency shift caused by high temperatures are addressed by using a proper antenna design, with parasitic patches, slots, and metal resonant cavities. The antenna prototype is characterized by the curved substrates and the conductive metals for the power dividers, the patch, and the ground plane; its performance is examined up to a temperature of 600 °C in a muffle furnace and compared with the results from the numerical analysis. The results show that the antenna can effectively function at 600 °C and even higher temperatures.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 340-353"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981919","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}
In underwater target search path planning, the accuracy of sonar models directly dictates the accurate assessment of search coverage. In contrast to physics-informed sonar models, traditional geometric sonar models fail to accurately characterize the complex influence of marine environments. To overcome these challenges, we propose an acoustic physics-informed intelligent path planning framework for underwater target search, integrating three core modules: The acoustic-physical modeling module adopts 3D ray-tracing theory and the active sonar equation to construct a physics-driven sonar detection model, explicitly accounting for environmental factors that influence sonar performance across heterogeneous spaces. The hybrid parallel computing module adopts a message passing interface (MPI)/open multi-processing (OpenMP) hybrid strategy for large-scale acoustic simulations, combining computational domain decomposition and physics-intensive task acceleration. The search path optimization module adopts the covariance matrix adaptation evolution algorithm to solve continuous optimization problems of heading angles, which ensures maximum search coverage for targets. Large-scale experiments conducted in the Pacific and Atlantic Oceans demonstrate the framework's effectiveness: (1) Precise capture of sonar detection range variations from 5.45 km to 50 km in heterogeneous marine environments. (2) Significant speedup of 453.43 × for acoustic physics modeling through hybrid parallelization. (3) Notable improvements of 7.23% in detection coverage and 15.86% reduction in optimization time compared to the optimal baseline method. The framework provides a robust solution for underwater search missions in complex marine environments.
{"title":"Acoustic physics-informed intelligent path planning framework for active sonar search","authors":"Siyuan Liao, Wenbin Xiao, Yongxian Wang, Zhao Sun, Houwang Tu, Wenfeng Liu","doi":"10.1016/j.dt.2025.08.008","DOIUrl":"10.1016/j.dt.2025.08.008","url":null,"abstract":"<div><div>In underwater target search path planning, the accuracy of sonar models directly dictates the accurate assessment of search coverage. In contrast to physics-informed sonar models, traditional geometric sonar models fail to accurately characterize the complex influence of marine environments. To overcome these challenges, we propose an acoustic physics-informed intelligent path planning framework for underwater target search, integrating three core modules: The acoustic-physical modeling module adopts 3D ray-tracing theory and the active sonar equation to construct a physics-driven sonar detection model, explicitly accounting for environmental factors that influence sonar performance across heterogeneous spaces. The hybrid parallel computing module adopts a message passing interface (MPI)/open multi-processing (OpenMP) hybrid strategy for large-scale acoustic simulations, combining computational domain decomposition and physics-intensive task acceleration. The search path optimization module adopts the covariance matrix adaptation evolution algorithm to solve continuous optimization problems of heading angles, which ensures maximum search coverage for targets. Large-scale experiments conducted in the Pacific and Atlantic Oceans demonstrate the framework's effectiveness: (1) Precise capture of sonar detection range variations from 5.45 km to 50 km in heterogeneous marine environments. (2) Significant speedup of 453.43 × for acoustic physics modeling through hybrid parallelization. (3) Notable improvements of 7.23% in detection coverage and 15.86% reduction in optimization time compared to the optimal baseline method. The framework provides a robust solution for underwater search missions in complex marine environments.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 354-376"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981914","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 : 2026-01-01DOI: 10.1016/j.dt.2025.08.004
Zhangjun Wu , Xianzhao Song , Shuxin Deng , Bingbing Yu , Yongxu Wang , Rhoda Afriyie Mensah , Suning Mei
To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations, high-energy metal powders (aluminum (Al), boron (B), and magnesium hydride (MgH2)) are incorporated into a liquid fuel primarily composed of diethyl ether (DEE) and isopropyl nitrate (IPN). The explosion characteristics of different solid-liquid fuel-air-explosive (FAE) under unconfined conditions are investigated using a high-speed camera, infrared thermal imaging, and a pressure measurement system. Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation, with aluminum exhibiting the most pronounced effect. Fuel 5# (45.4 wt% DEE, 9.2 wt% IPN, 29.5 wt% Al, 9.1 wt% B, 6.8 wt% MgH2) exhibits superior explosion performance, achieving higher values of overpressure, impulse, and thermal radiation damage during the detonation stage compared to other fuels. However, Fuel 5# also displays faster decay rates, attributed to accelerated heat release rates induced by B and MgH2 powders. This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance, providing critical insights for optimizing composite fuel design.
{"title":"Detonation characteristics of the solid-liquid mixed fuel cloud of Al/B/MgH2/DEE/IPN","authors":"Zhangjun Wu , Xianzhao Song , Shuxin Deng , Bingbing Yu , Yongxu Wang , Rhoda Afriyie Mensah , Suning Mei","doi":"10.1016/j.dt.2025.08.004","DOIUrl":"10.1016/j.dt.2025.08.004","url":null,"abstract":"<div><div>To elucidate the dispersion and explosion characteristics of multi-metal powder and liquid composite fuel formulations, high-energy metal powders (aluminum (Al), boron (B), and magnesium hydride (MgH<sub>2</sub>)) are incorporated into a liquid fuel primarily composed of diethyl ether (DEE) and isopropyl nitrate (IPN). The explosion characteristics of different solid-liquid fuel-air-explosive (FAE) under unconfined conditions are investigated using a high-speed camera, infrared thermal imaging, and a pressure measurement system. Results demonstrate that high-energy metal powders significantly enhance detonation energy dissipation, with aluminum exhibiting the most pronounced effect. Fuel 5# (45.4 wt% DEE, 9.2 wt% IPN, 29.5 wt% Al, 9.1 wt% B, 6.8 wt% MgH<sub>2</sub>) exhibits superior explosion performance, achieving higher values of overpressure, impulse, and thermal radiation damage during the detonation stage compared to other fuels. However, Fuel 5# also displays faster decay rates, attributed to accelerated heat release rates induced by B and MgH<sub>2</sub> powders. This study reveals that different metal powders in solid-liquid FAE exhibit distinct enhancements in explosion performance, providing critical insights for optimizing composite fuel design.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 377-388"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981915","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 : 2026-01-01DOI: 10.1016/j.dt.2025.07.020
Feilong Jiang, Hutao Cui, Yuqing Li, Minqiang Xu, Rixin Wang
In the field of intelligent air combat, real-time and accurate recognition of within-visual-range (WVR) maneuver actions serves as the foundational cornerstone for constructing autonomous decision-making systems. However, existing methods face two major challenges: traditional feature engineering suffers from insufficient effective dimensionality in the feature space due to kinematic coupling, making it difficult to distinguish essential differences between maneuvers, while end-to-end deep learning models lack controllability in implicit feature learning and fail to model high-order long-range temporal dependencies. This paper proposes a trajectory feature pre-extraction method based on a Long-range Masked Autoencoder (LMAE), incorporating three key innovations: (1) Random Fragment High-ratio Masking (RFH-Mask), which enforces the model to learn long-range temporal correlations by masking 80% of trajectory data while retaining continuous fragments; (2) Kalman Filter-Guided Objective Function (KFG-OF), integrating trajectory continuity constraints to align the feature space with kinematic principles; and (3) Two-stage Decoupled Architecture, enabling efficient and controllable feature learning through unsupervised pre-training and frozen-feature transfer. Experimental results demonstrate that LMAE significantly improves the average recognition accuracy for 20-class maneuvers compared to traditional end-to-end models, while significantly accelerating convergence speed. The contributions of this work lie in: introducing high-masking-rate autoencoders into low-information-density trajectory analysis, proposing a feature engineering framework with enhanced controllability and efficiency, and providing a novel technical pathway for intelligent air combat decision-making systems.
{"title":"Long-range masked autoencoder for pre-extraction of trajectory features in within-visual-range maneuver recognition","authors":"Feilong Jiang, Hutao Cui, Yuqing Li, Minqiang Xu, Rixin Wang","doi":"10.1016/j.dt.2025.07.020","DOIUrl":"10.1016/j.dt.2025.07.020","url":null,"abstract":"<div><div>In the field of intelligent air combat, real-time and accurate recognition of within-visual-range (WVR) maneuver actions serves as the foundational cornerstone for constructing autonomous decision-making systems. However, existing methods face two major challenges: traditional feature engineering suffers from insufficient effective dimensionality in the feature space due to kinematic coupling, making it difficult to distinguish essential differences between maneuvers, while end-to-end deep learning models lack controllability in implicit feature learning and fail to model high-order long-range temporal dependencies. This paper proposes a trajectory feature pre-extraction method based on a Long-range Masked Autoencoder (LMAE), incorporating three key innovations: (1) Random Fragment High-ratio Masking (RFH-Mask), which enforces the model to learn long-range temporal correlations by masking 80% of trajectory data while retaining continuous fragments; (2) Kalman Filter-Guided Objective Function (KFG-OF), integrating trajectory continuity constraints to align the feature space with kinematic principles; and (3) Two-stage Decoupled Architecture, enabling efficient and controllable feature learning through unsupervised pre-training and frozen-feature transfer. Experimental results demonstrate that LMAE significantly improves the average recognition accuracy for 20-class maneuvers compared to traditional end-to-end models, while significantly accelerating convergence speed. The contributions of this work lie in: introducing high-masking-rate autoencoders into low-information-density trajectory analysis, proposing a feature engineering framework with enhanced controllability and efficiency, and providing a novel technical pathway for intelligent air combat decision-making systems.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 301-315"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981812","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 : 2026-01-01DOI: 10.1016/j.dt.2025.07.025
Yuxuan Qi , Liang Mao , Chunlan Jiang , Guitao Liu , Kongxun Zhao , Mengchen Zhang
This paper prepared a novel as-cast W-Zr-Ti metallic ESM using high-frequency vacuum induction melting technique. The above ESM performs a typical elastic-brittle material feature and strain rate strengthening behavior. The specimens exhibit violent chemical reaction during the fracture process under the impact loading, and the size distribution of their residual debris follows Rosin-Rammler model. The dynamic fracture toughness is obtained by the fitting of debris length scale, approximately 1.87 MPa·m1/2. Microstructure observation on residual debris indicates that the failure process is determined by primary crack propagation under quasi-static compression, while it is affected by multiple cracks propagation in both particle and matrix in the case of dynamic impact. Impact test demonstrates that the novel energetic fragment performs brilliant penetration and combustion effect behind the front target, leading to the effective ignition of fuel tank. For the brittleness of as-cast W-Zr-Ti ESM, further study conducted bond-based peridynamic (BB-PD) C++ computational code to simulate its fracture behavior during penetration. The BB-PD method successfully captured the fracture process and debris cloud formation of the energetic fragment. This paper explores a novel as-cast metallic ESM, and provides an available numerical avenue to the simulation of brittle energetic fragment.
{"title":"Dynamic fracture behavior and coupled impact effect of as-cast W-Zr-Ti energetic structural material","authors":"Yuxuan Qi , Liang Mao , Chunlan Jiang , Guitao Liu , Kongxun Zhao , Mengchen Zhang","doi":"10.1016/j.dt.2025.07.025","DOIUrl":"10.1016/j.dt.2025.07.025","url":null,"abstract":"<div><div>This paper prepared a novel as-cast W-Zr-Ti metallic ESM using high-frequency vacuum induction melting technique. The above ESM performs a typical elastic-brittle material feature and strain rate strengthening behavior. The specimens exhibit violent chemical reaction during the fracture process under the impact loading, and the size distribution of their residual debris follows Rosin-Rammler model. The dynamic fracture toughness is obtained by the fitting of debris length scale, approximately 1.87 MPa·m<sup>1/2</sup>. Microstructure observation on residual debris indicates that the failure process is determined by primary crack propagation under quasi-static compression, while it is affected by multiple cracks propagation in both particle and matrix in the case of dynamic impact. Impact test demonstrates that the novel energetic fragment performs brilliant penetration and combustion effect behind the front target, leading to the effective ignition of fuel tank. For the brittleness of as-cast W-Zr-Ti ESM, further study conducted bond-based peridynamic (BB-PD) C++ computational code to simulate its fracture behavior during penetration. The BB-PD method successfully captured the fracture process and debris cloud formation of the energetic fragment. This paper explores a novel as-cast metallic ESM, and provides an available numerical avenue to the simulation of brittle energetic fragment.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 422-435"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981916","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 : 2026-01-01DOI: 10.1016/j.dt.2025.09.002
Pengfei Ouyang , Yang Liu , Zhaoyang Zhang , Xiaolei Chen , Yufeng Wang , Hao Zhu , Kun Xu , Jingtao Wang , Xiankai Meng , Shu Huang
The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency, making it imperative to address the challenge of efficiently and accurately machining film cooling holes. It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes, a consequence of the severe thermal defects. The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage, thus representing a highly promising solution to this challenge. However, significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability, thereby reducing machining quality. In order to surmount these challenges, a novel method has been proposed, namely an ultrasonic shock water flow-assisted picosecond laser drilling technique. Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism. The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming, thereby avoiding the accumulation of bubbles and products. Subsequent analysis, comparing the process performance in micro-hole machining, confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation, thus significantly improving micro-hole quality. Furthermore, the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated. The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels, in conjunction with reduced laser frequency and scanning velocity. The taper of the micro-holes produced by the new method was reduced by more than 25% compared with the other conventional methods.
{"title":"Multi-energy field coupling analysis and experimental validation of picosecond laser drilling assisted by ultrasonic shock-induced water flow","authors":"Pengfei Ouyang , Yang Liu , Zhaoyang Zhang , Xiaolei Chen , Yufeng Wang , Hao Zhu , Kun Xu , Jingtao Wang , Xiankai Meng , Shu Huang","doi":"10.1016/j.dt.2025.09.002","DOIUrl":"10.1016/j.dt.2025.09.002","url":null,"abstract":"<div><div>The latest generation of aero engines has set higher standards for thrust-to-weight ratio and energy conversion efficiency, making it imperative to address the challenge of efficiently and accurately machining film cooling holes. It has been demonstrated that conventional long-pulse lasers are incapable of meeting the elevated quality surface finish requirements for these holes, a consequence of the severe thermal defects. The employment of backside water-assisted laser drilling technology confers a number of distinct advantages in terms of mitigating laser thermal damage, thus representing a highly promising solution to this challenge. However, significant accumulation of bubbles and machining products during the backside water-assisted laser drilling process has been demonstrated to have a detrimental effect on laser transmission and machining stability, thereby reducing machining quality. In order to surmount these challenges, a novel method has been proposed, namely an ultrasonic shock water flow-assisted picosecond laser drilling technique. Numerical models for ultrasonic acoustic streaming and particle tracking for machining product transport have been established to investigate the mechanism. The simulation results demonstrated that the majority of the machining products could rapidly move away from the machining area because of the action of acoustic streaming, thereby avoiding the accumulation of bubbles and products. Subsequent analysis, comparing the process performance in micro-hole machining, confirmed that the ultrasonic field could effectively eliminate bubble and chip accumulation, thus significantly improving micro-hole quality. Furthermore, the impact of ultrasonic and laser parameters on micro-hole quality under varying machining methods was thoroughly investigated. The findings demonstrated that the novel methodology outlined in this study yielded superior-quality micro-holes at elevated ultrasonic and laser power levels, in conjunction with reduced laser frequency and scanning velocity. The taper of the micro-holes produced by the new method was reduced by more than 25% compared with the other conventional methods.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 130-154"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145982122","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 : 2026-01-01DOI: 10.1016/j.dt.2025.10.003
Yanbing Wang , Honghao Yue , Jun Wu , Xueting Pan , Fei Yang , Yong Zhao , Jicheng Liu , Xue Bai
Conventional locking/release mechanisms often face challenges in aircraft wing separation processes, such as excessive impact loads and insufficient synchronization. These may cause structural damage to the airframe or attitude instability, seriously compromising mission reliability. To address this engineering challenge, this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy. Through establishing a DOF constraint framework system, this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process, reveals the generation mechanism of impact loads, and conducts research on low-impact design based on energy conversion strategy. Building on this foundation, a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed, which increases frictional contact time and reduces the energy release rate, thereby achieving low-impact characteristics. The mechanism's performance was validated through physical prototype development and systematic functional testing (including unlocking force, synchronization, and impact tests). Experimental results demonstrate: (1) Under 14 kN preload condition, the maximum unlocking force was only 92.54 N, showing a linear relationship with preload that satisfies the "strong-connection/weak-unlock" design requirement; (2) Wing separation was completed within 46 ms, with synchronization time difference among three separation mechanisms stably controlled within 12–14 ms, proving rapid and reliable operation; (3) The unlocking impact acceleration ranged between 26 and 73 g, below the 100 g design limit, confirming the effectiveness of the energy conversion strategy. The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies. The synergistic optimization mechanism of "structural load reduction and performance improvement" provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.
{"title":"Design and experimental validation of a low-impact wing locking/release mechanism based on energy conversion strategy","authors":"Yanbing Wang , Honghao Yue , Jun Wu , Xueting Pan , Fei Yang , Yong Zhao , Jicheng Liu , Xue Bai","doi":"10.1016/j.dt.2025.10.003","DOIUrl":"10.1016/j.dt.2025.10.003","url":null,"abstract":"<div><div>Conventional locking/release mechanisms often face challenges in aircraft wing separation processes, such as excessive impact loads and insufficient synchronization. These may cause structural damage to the airframe or attitude instability, seriously compromising mission reliability. To address this engineering challenge, this paper proposes a multi-point low-impact locking/release mechanism based on the mobility model and energy conversion strategy. Through establishing a DOF constraint framework system, this paper systematically analyzes the energy transfer and conversion characteristics during the wing separation process, reveals the generation mechanism of impact loads, and conducts research on low-impact design based on energy conversion strategy. Building on this foundation, a single-point locking/release mechanism employing parallel trapezoidal key shaft structure was designed, which increases frictional contact time and reduces the energy release rate, thereby achieving low-impact characteristics. The mechanism's performance was validated through physical prototype development and systematic functional testing (including unlocking force, synchronization, and impact tests). Experimental results demonstrate: (1) Under 14 kN preload condition, the maximum unlocking force was only 92.54 N, showing a linear relationship with preload that satisfies the \"strong-connection/weak-unlock\" design requirement; (2) Wing separation was completed within 46 ms, with synchronization time difference among three separation mechanisms stably controlled within 12–14 ms, proving rapid and reliable operation; (3) The unlocking impact acceleration ranged between 26 and 73 g, below the 100 g design limit, confirming the effectiveness of the energy conversion strategy. The proposed low-impact locking/release mechanism design method based on energy conversion strategy resolves the traditional challenges of high impact and synchronization deficiencies. The synergistic optimization mechanism of \"structural load reduction and performance improvement\" provides a highly reliable technical solution for wing separable mechanisms while offering novel design insights for wing connection/separation systems engineering.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 241-256"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981806","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 : 2026-01-01DOI: 10.1016/j.dt.2025.07.028
Rui Liu , Chaoyang Zhang , Linyuan Wang , Zhiyu Huang , Jian Liu
Conventional error cancellation approaches separate molecules into smaller fragments and sum the errors of all fragments to counteract the overall computational error of the parent molecules. However, these approaches may be ineffective for systems with strong localized chemical effects, as fragmenting specific substructures into simpler chemical bonds can introduce additional errors instead of mitigating them. To address this issue, we propose the Substructure-Preserved Connection-Based Hierarchy (SCBH), a method that automatically identifies and freezes substructures with significant local chemical effects prior to molecular fragmentation. The SCBH is validated by the gas-phase enthalpy of formation calculation of CHNO molecules. Therein, based on the atomization scheme, the reference and test values are derived at the levels of Gaussian-4 (G4) and M062X/6-31+G(2df, p), respectively. Compared to commonly used approaches, SCBH reduces the average computational error by half and requires only 15% of the computational cost of G4 to achieve comparable accuracy. Since different types of local effect structures have differentiated influences on gas-phase enthalpy of formation, substituents with strong electronic effects should be retained preferentially. SCBH can be readily extended to diverse classes of organic compounds. Its workflow and source code allow flexible customization of molecular moieties, including azide, carboxyl, trinitromethyl, phenyl, and others. This strategy facilitates accurate, rapid, and automated computations and corrections, making it well-suited for high-throughput molecular screening and dataset construction for gas-phase enthalpy of formation.
{"title":"Retaining local chemical effects: An error cancellation strategy for calculating standard gas-phase enthalpy of formation","authors":"Rui Liu , Chaoyang Zhang , Linyuan Wang , Zhiyu Huang , Jian Liu","doi":"10.1016/j.dt.2025.07.028","DOIUrl":"10.1016/j.dt.2025.07.028","url":null,"abstract":"<div><div>Conventional error cancellation approaches separate molecules into smaller fragments and sum the errors of all fragments to counteract the overall computational error of the parent molecules. However, these approaches may be ineffective for systems with strong localized chemical effects, as fragmenting specific substructures into simpler chemical bonds can introduce additional errors instead of mitigating them. To address this issue, we propose the Substructure-Preserved Connection-Based Hierarchy (SCBH), a method that automatically identifies and freezes substructures with significant local chemical effects prior to molecular fragmentation. The SCBH is validated by the gas-phase enthalpy of formation calculation of CHNO molecules. Therein, based on the atomization scheme, the reference and test values are derived at the levels of Gaussian-4 (G4) and M062X/6-31+G(2df, p), respectively. Compared to commonly used approaches, SCBH reduces the average computational error by half and requires only 15% of the computational cost of G4 to achieve comparable accuracy. Since different types of local effect structures have differentiated influences on gas-phase enthalpy of formation, substituents with strong electronic effects should be retained preferentially. SCBH can be readily extended to diverse classes of organic compounds. Its workflow and source code allow flexible customization of molecular moieties, including azide, carboxyl, trinitromethyl, phenyl, and others. This strategy facilitates accurate, rapid, and automated computations and corrections, making it well-suited for high-throughput molecular screening and dataset construction for gas-phase enthalpy of formation.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 172-179"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981814","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 : 2026-01-01DOI: 10.1016/j.dt.2025.05.022
Noha M. Hassan , Zied Bahroun , Mahmoud I. Awad , Rami As'ad , El-Cheikh Amer Kaiss
Variable stiffness composites present a promising solution for mitigating impact loads via varying the fiber volume fraction layer-wise, thereby adjusting the panel's stiffness. Since each layer of the composite may be affected by a different failure mode, the optimal fiber volume fraction to suppress damage initiation and evolution is different across the layers. This research examines how re-allocating the fibers layer-wise enhances the composites' impact resistance. In this study, constant stiffness panels with the same fiber volume fraction throughout the layers are compared to variable stiffness ones by varying volume fraction layer-wise. A method is established that utilizes numerical analysis coupled with optimization techniques to determine the optimal fiber volume fraction in both scenarios. Three different reinforcement fibers (Kevlar, carbon, and glass) embedded in epoxy resin were studied. Panels were manufactured and tested under various loading conditions to validate results. Kevlar reinforcement revealed the highest tensile toughness, followed by carbon and then glass fibers. Varying reinforcement volume fraction significantly influences failure modes. Higher fractions lead to matrix cracking and debonding, while lower fractions result in more fiber breakage. The optimal volume fraction for maximizing fiber breakage energy is around 45%, whereas it is about 90% for matrix cracking and debonding. A drop tower test was used to examine the composite structure's behavior under low-velocity impact, confirming the superiority of Kevlar-reinforced composites with variable stiffness. Conversely, glass-reinforced composites with constant stiffness revealed the lowest performance with the highest deflection. Across all reinforcement materials, the variable stiffness structure consistently outperformed its constant stiffness counterpart.
{"title":"Optimized fiber allocation for enhanced impact resistance in composites through damage mode suppression","authors":"Noha M. Hassan , Zied Bahroun , Mahmoud I. Awad , Rami As'ad , El-Cheikh Amer Kaiss","doi":"10.1016/j.dt.2025.05.022","DOIUrl":"10.1016/j.dt.2025.05.022","url":null,"abstract":"<div><div>Variable stiffness composites present a promising solution for mitigating impact loads via varying the fiber volume fraction layer-wise, thereby adjusting the panel's stiffness. Since each layer of the composite may be affected by a different failure mode, the optimal fiber volume fraction to suppress damage initiation and evolution is different across the layers. This research examines how re-allocating the fibers layer-wise enhances the composites' impact resistance. In this study, constant stiffness panels with the same fiber volume fraction throughout the layers are compared to variable stiffness ones by varying volume fraction layer-wise. A method is established that utilizes numerical analysis coupled with optimization techniques to determine the optimal fiber volume fraction in both scenarios. Three different reinforcement fibers (Kevlar, carbon, and glass) embedded in epoxy resin were studied. Panels were manufactured and tested under various loading conditions to validate results. Kevlar reinforcement revealed the highest tensile toughness, followed by carbon and then glass fibers. Varying reinforcement volume fraction significantly influences failure modes. Higher fractions lead to matrix cracking and debonding, while lower fractions result in more fiber breakage. The optimal volume fraction for maximizing fiber breakage energy is around 45%, whereas it is about 90% for matrix cracking and debonding. A drop tower test was used to examine the composite structure's behavior under low-velocity impact, confirming the superiority of Kevlar-reinforced composites with variable stiffness. Conversely, glass-reinforced composites with constant stiffness revealed the lowest performance with the highest deflection. Across all reinforcement materials, the variable stiffness structure consistently outperformed its constant stiffness counterpart.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 316-329"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981918","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 : 2026-01-01DOI: 10.1016/j.dt.2025.04.008
J Jefferson Andrew , Jabir Ubaid , Mohammed Ayaz Uddin , Omar Waqas Saadi , Kamran Ahmed Khan , Rehan Umer , Andreas Schiffer
Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices, mimicking the architecture of the marine sponge organism Euplectella aspergillum. These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing (DLP). The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices. This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice, due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-by-layer under impact. By adjusting the thickness ratio in the sea sponge lattice, up to 76.7% increment in energy absorption is attained. It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight, such as hexagonal honeycombs, confirming their significant potential for impact mitigation. Additionally, this research highlights the enhancements in energy absorption achieved by adding a small amount (0.015 phr) of Multi-Walled Carbon Nanotubes (MWCNTs) to the photocurable resin, thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.
{"title":"Energy absorption characteristics of additively manufactured sea sponge-inspired lattice structures under low-velocity impact loading","authors":"J Jefferson Andrew , Jabir Ubaid , Mohammed Ayaz Uddin , Omar Waqas Saadi , Kamran Ahmed Khan , Rehan Umer , Andreas Schiffer","doi":"10.1016/j.dt.2025.04.008","DOIUrl":"10.1016/j.dt.2025.04.008","url":null,"abstract":"<div><div>Low-velocity impact tests are carried out to explore the energy absorption characteristics of bio-inspired lattices, mimicking the architecture of the marine sponge organism <em>Euplectella aspergillum</em>. These sea sponge-inspired lattice structures feature a square-grid 2D lattice with double diagonal bracings and are additively manufactured via digital light processing (DLP). The collapse strength and energy absorption capacity of sea sponge lattice structures are evaluated under various impact conditions and are compared to those of their constituent square-grid and double diagonal lattices. This study demonstrates that sea sponge lattices can achieve an 11-fold increase in energy absorption compared to the square-grid lattice, due to the stabilizing effect of the double diagonal bracings prompting the structure to collapse layer-by-layer under impact. By adjusting the thickness ratio in the sea sponge lattice, up to 76.7% increment in energy absorption is attained. It is also shown that sea-sponge lattices outperform well-established energy-absorbing materials of equal weight, such as hexagonal honeycombs, confirming their significant potential for impact mitigation. Additionally, this research highlights the enhancements in energy absorption achieved by adding a small amount (0.015 phr) of Multi-Walled Carbon Nanotubes (MWCNTs) to the photocurable resin, thus unlocking new possibilities for the design of innovative lightweight structures with multifunctional attributes.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"55 ","pages":"Pages 118-129"},"PeriodicalIF":5.9,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981931","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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