Pub Date : 2026-02-06DOI: 10.3881/j.issn.1000-503X.17210
Meng-Chun Gong, Hui Pan, Hui Liu, Kuang Tong, Jiao Li, Yong-Hui Ma, Wei Chen, Yan Hou, Li Hong, Bo Zhang, Bo-Han Zhang, Zhi-Rong Zeng, Xun-Ming Ji
To cultivate composite medical professionals capable of adapting to the development of intelligent healthcare,this consensus is grounded in the competency-based medical education,integrating the competency model and Miller's pyramid of clinical competence. A two-round Delphi method involving a multidisciplinary expert panel was conducted,combined with a systematic literature review,to develop a 21-indicator artificial intelligence(AI) literacy competency list for medical students across three domains:knowledge (8 indicators),skills (8 indicators),and attitudes (5 indicators). Furthermore,the consensus proposes a practical assessment system:standardized testing for the knowledge domain,situational judgment tests for the attitudes domain,and objective structured clinical examinations incorporating AI-related scenarios for the skills domain. In addition,a longitudinal assessment strategy spanning the phases of admission,preclinical training,and clinical training is recommended. The competency list and assessment framework established in this consensus demonstrate strong scientific rigor,authority,and practical applicability,and can serve as an important reference for medical schools seeking to advance the deep integration of AI and medical education and to cultivate composite medical talents suited to the era of intelligent healthcare.
{"title":"Expert Consensus on the Artificial Intelligence Proficiency Competency List and Assessment Framework for Medical Students (2025 Edition).","authors":"Meng-Chun Gong, Hui Pan, Hui Liu, Kuang Tong, Jiao Li, Yong-Hui Ma, Wei Chen, Yan Hou, Li Hong, Bo Zhang, Bo-Han Zhang, Zhi-Rong Zeng, Xun-Ming Ji","doi":"10.3881/j.issn.1000-503X.17210","DOIUrl":"https://doi.org/10.3881/j.issn.1000-503X.17210","url":null,"abstract":"<p><p>To cultivate composite medical professionals capable of adapting to the development of intelligent healthcare,this consensus is grounded in the competency-based medical education,integrating the competency model and Miller's pyramid of clinical competence. A two-round Delphi method involving a multidisciplinary expert panel was conducted,combined with a systematic literature review,to develop a 21-indicator artificial intelligence(AI) literacy competency list for medical students across three domains:knowledge (8 indicators),skills (8 indicators),and attitudes (5 indicators). Furthermore,the consensus proposes a practical assessment system:standardized testing for the knowledge domain,situational judgment tests for the attitudes domain,and objective structured clinical examinations incorporating AI-related scenarios for the skills domain. In addition,a longitudinal assessment strategy spanning the phases of admission,preclinical training,and clinical training is recommended. The competency list and assessment framework established in this consensus demonstrate strong scientific rigor,authority,and practical applicability,and can serve as an important reference for medical schools seeking to advance the deep integration of AI and medical education and to cultivate composite medical talents suited to the era of intelligent healthcare.</p>","PeriodicalId":6919,"journal":{"name":"中国医学科学院学报","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2026-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146123423","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.001
Byeong-Joo Kim , Ji Eun Lee , Chang-Bin Oh , Doo Hyun Choi , Man Young Lee , Dae Young Jo , Shin Kim
Unmanned combat aerial vehicles require lightweight, stealth-capable exhaust systems. However, traditional metallic nozzles increase radar detectability and reduce range, while advanced composites offer high performance but are expensive. Therefore, to improve the operational range and survivability of unmanned combat aerial vehicles, a lightweight, high-temperature-resistant, oxidation-resistant, and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles. The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process, accommodating the complex geometry and large size (length: 1.8 m, width: 0.8 m). The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix, which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature (700 °C) oxidizing environments typical of engine exhaust gases. The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles, making filament winding difficult. These challenges are addressed by optimizing resin viscosity and winding pattern design. As a result, the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68% after pyrolysis, compared with that of the non-optimized specimens. In addition, the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%, respectively, compared to those of the non-densified composite. High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability. Furthermore, when compared with carbon fiber-reinforced ceramic matrix composites, the developed composite exhibits a permittivity at least two levels lower and a reflection loss below −7 dB within the frequency range of 9.3–10.9 GHz, underscoring its superior electromagnetic stealth performance.
{"title":"Development of silicon carbide fiber-reinforced silicon oxycarbide composites for low-observable unmanned aerial vehicle exhaust nozzles via filament winding, and polymer infiltration and pyrolysis","authors":"Byeong-Joo Kim , Ji Eun Lee , Chang-Bin Oh , Doo Hyun Choi , Man Young Lee , Dae Young Jo , Shin Kim","doi":"10.1016/j.dt.2025.09.001","DOIUrl":"10.1016/j.dt.2025.09.001","url":null,"abstract":"<div><div>Unmanned combat aerial vehicles require lightweight, stealth-capable exhaust systems. However, traditional metallic nozzles increase radar detectability and reduce range, while advanced composites offer high performance but are expensive. Therefore, to improve the operational range and survivability of unmanned combat aerial vehicles, a lightweight, high-temperature-resistant, oxidation-resistant, and low-observable composite exhaust nozzle is developed to replace conventional metallic straight-type nozzles. The nozzle features a double serpentine shape to reduce radar and infrared signatures and is manufactured as a monolithic structure using the filament winding process, accommodating the complex geometry and large size (length: 1.8 m, width: 0.8 m). The exhaust nozzle consists of a ceramic matrix composite made of silicon carbide fibers and a silicon oxycarbide matrix, which absorbs and scatters radio frequency signals while withstanding prolonged exposure to high-temperature (700 °C) oxidizing environments typical of engine exhaust gases. The polysiloxane resin used to produce the silicon oxycarbide matrix poses significant challenges owing to its low tackiness and high viscosity variations depending on the presence of nanoparticles, making filament winding difficult. These challenges are addressed by optimizing resin viscosity and winding pattern design. As a result, the tensile strength of the composite specimens fabricated with the optimized viscosity increases by 228.03% before pyrolysis and 97.68% after pyrolysis, compared with that of the non-optimized specimens. In addition, the density and tensile strength of the composite processed via three cycles of polymer infiltration and pyrolysis increased by 13.08% and 80.37%, respectively, compared to those of the non-densified composite. High-temperature oxidation and flame tests demonstrate exceptional thermal and oxidative stability. Furthermore, when compared with carbon fiber-reinforced ceramic matrix composites, the developed composite exhibits a permittivity at least two levels lower and a reflection loss below −7 dB within the frequency range of 9.3–10.9 GHz, underscoring its superior electromagnetic stealth performance.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 49-65"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116735","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.026
Yandan Chen , Junyi Hua , Nan Wang , Jun Wu , Bixiong Bie , Yonggang Lu , Bo Li , Yang Cai , Shengnian Luo
We investigate the effects of projectile material on high-speed penetration/perforation of Inconel 718 alloy (IN718) plates. High-speed ballistic impact tests are conducted on 2 mm-thickness IN718 plates with 5-mm-diameter stainless steel 304 (SS304), Ti alloy TC4, and Al alloy AA1060 spherical projectiles. The impact processes are captured with high-speed photography. Optical and scanning electron microscopy and laser scan are conducted on recovered projectiles and targets. Finite element models of the ballistic impact are established based on the coupled Eulerian–Lagrangian algorithm with the Johnson–Cook constitutive model and failure criterion, and can well reproduce the experimental results. The experimental and simulated data related to projectile dynamics, and the geometries of postmortem projectiles and bullet holes are analyzed with phenomenological models. Projectile velocity evolution can be described with hydrodynamic models of penetration. Dimensional analysis reveals a universal relationship between the bullet hole expansion coefficient and the normalized dynamic pressure, regardless of the projectile material. However, the projectile material does affect projectile deformation, bullet hole size, and energy absorption of target.
{"title":"Effects of projectile material on high-speed penetration/perforation of Inconel 718 alloy plates: Experiments and simulations","authors":"Yandan Chen , Junyi Hua , Nan Wang , Jun Wu , Bixiong Bie , Yonggang Lu , Bo Li , Yang Cai , Shengnian Luo","doi":"10.1016/j.dt.2025.09.026","DOIUrl":"10.1016/j.dt.2025.09.026","url":null,"abstract":"<div><div>We investigate the effects of projectile material on high-speed penetration/perforation of Inconel 718 alloy (IN718) plates. High-speed ballistic impact tests are conducted on 2 mm-thickness IN718 plates with 5-mm-diameter stainless steel 304 (SS304), Ti alloy TC4, and Al alloy AA1060 spherical projectiles. The impact processes are captured with high-speed photography. Optical and scanning electron microscopy and laser scan are conducted on recovered projectiles and targets. Finite element models of the ballistic impact are established based on the coupled Eulerian–Lagrangian algorithm with the Johnson–Cook constitutive model and failure criterion, and can well reproduce the experimental results. The experimental and simulated data related to projectile dynamics, and the geometries of postmortem projectiles and bullet holes are analyzed with phenomenological models. Projectile velocity evolution can be described with hydrodynamic models of penetration. Dimensional analysis reveals a universal relationship between the bullet hole expansion coefficient and the normalized dynamic pressure, regardless of the projectile material. However, the projectile material does affect projectile deformation, bullet hole size, and energy absorption of target.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 367-383"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116793","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.029
Zhiqi Liu , Mingqiang Luo , Yulu Ma , Chenguang Xing , Ruo Wang , Daheng Chen , Xiaolu Wang
Evaluating Unmanned Aerial Vehicle (UAV) systems within a System-of-Systems (SoS) environment helps clarify their contribution to the overall combat capability and supports effectiveness-oriented system optimization. When assessing decision systems in such an environment, cross-level modeling and simulation are required, which often face a trade-off between low modeling cost and high simulation accuracy, while the credibility of results remains challenging to ensure. To address these issues, this study proposes a hybrid-granularity Hardware-In-the-Loop (HIL) SoS environment construction method based on Graphical Evaluation and Review Technique (GERT). The method employs GERT to analyze the relationships between simulation systems, the System Under Test (SUT), and mission outcomes, thereby determining the required model precision for different systems. A dynamic resource allocation algorithm is applied to adjust model granularity on demand, ensuring high-fidelity simulation under constrained total cost. Additionally, GERT estimates the computational frequency and communication bandwidth requirements of the SUT, guiding hardware selection to enhance simulation credibility. A UAV maritime combat case study was conducted for validation. The results demonstrate that, compared to the flat modeling approach, the hybrid-granularity scenario based on GERT analysis achieves higher simulation accuracy with lower overall model complexity. The coefficient of variation in evaluation results significantly decreases in HIL simulations compared to virtual simulations, confirming improved credibility. Under the hybrid-granularity HIL scenario, the decision system was evaluated from an effectiveness perspective, identifying the most sensitive performance parameter. Subsequent targeted optimization led to an 11.90% improvement in effectiveness, validating the method's practical utility.
在系统的系统（so）环境中评估无人机（UAV）系统有助于阐明其对整体作战能力的贡献，并支持以有效性为导向的系统优化。在这种环境下对决策系统进行评估时，需要进行跨层建模和仿真，这往往面临着低建模成本和高仿真精度之间的权衡，而结果的可信度仍然难以保证。为了解决这些问题，本研究提出了一种基于图形评价与评审技术（GERT）的混合粒度硬件在环（HIL） SoS环境构建方法。该方法利用GERT分析仿真系统、被测系统（System Under Test， SUT）和任务结果之间的关系，从而确定不同系统所需的模型精度。采用动态资源分配算法按需调整模型粒度，保证了总成本约束下的高保真仿真。此外，GERT估计SUT的计算频率和通信带宽需求，指导硬件选择以提高仿真可信度。进行了无人机海上作战案例研究以进行验证。结果表明，与平面建模方法相比，基于GERT分析的混合粒度场景在整体模型复杂度较低的情况下实现了更高的仿真精度。与虚拟仿真相比，HIL仿真中评估结果的变异系数显著降低，证实了可信度的提高。在混合粒度HIL场景下，从有效性角度对决策系统进行评价，找出最敏感的性能参数。随后的针对性优化使效率提高了11.90%，验证了该方法的实用性。
{"title":"A methodology for constructing the system-of-systems environment to evaluate UAV decision systems","authors":"Zhiqi Liu , Mingqiang Luo , Yulu Ma , Chenguang Xing , Ruo Wang , Daheng Chen , Xiaolu Wang","doi":"10.1016/j.dt.2025.09.029","DOIUrl":"10.1016/j.dt.2025.09.029","url":null,"abstract":"<div><div>Evaluating Unmanned Aerial Vehicle (UAV) systems within a System-of-Systems (SoS) environment helps clarify their contribution to the overall combat capability and supports effectiveness-oriented system optimization. When assessing decision systems in such an environment, cross-level modeling and simulation are required, which often face a trade-off between low modeling cost and high simulation accuracy, while the credibility of results remains challenging to ensure. To address these issues, this study proposes a hybrid-granularity Hardware-In-the-Loop (HIL) SoS environment construction method based on Graphical Evaluation and Review Technique (GERT). The method employs GERT to analyze the relationships between simulation systems, the System Under Test (SUT), and mission outcomes, thereby determining the required model precision for different systems. A dynamic resource allocation algorithm is applied to adjust model granularity on demand, ensuring high-fidelity simulation under constrained total cost. Additionally, GERT estimates the computational frequency and communication bandwidth requirements of the SUT, guiding hardware selection to enhance simulation credibility. A UAV maritime combat case study was conducted for validation. The results demonstrate that, compared to the flat modeling approach, the hybrid-granularity scenario based on GERT analysis achieves higher simulation accuracy with lower overall model complexity. The coefficient of variation in evaluation results significantly decreases in HIL simulations compared to virtual simulations, confirming improved credibility. Under the hybrid-granularity HIL scenario, the decision system was evaluated from an effectiveness perspective, identifying the most sensitive performance parameter. Subsequent targeted optimization led to an 11.90% improvement in effectiveness, validating the method's practical utility.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 337-351"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116795","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}
Material phase-transition represents a significant phenomenon and mechanism in the context of hypervelocity protection. This study presents a thorough analysis of the phase-transition phenomena induced by shock pressure as the shock wave propagates initially to the rear of the projectile. The shock wave that induces a phase-transition is commonly referred to as a macroscopic phase-transition wave, whereas the interface that separates the distinct phases is referred to as macroscopic phase-boundary. The contact interface between the spherical projectile and the thin plate, characterized by its curved surface, plays a significant role in the nonlinear propagation and evolution of wave systems. The pressure distribution along the central axis of a spherical projectile is derived in accordance with the linear decay law observed for axial pressure. On this basis, a quadratic function is employed to characterize the trend of changes in wave front pressure, thereby facilitating the establishment of a model for wave front pressure distribution. Using the phase-transition pressure criterion for materials, the wave front phase evolution process is derived, and the macroscopic phase-boundary is determined. Based on the geometric propagation model (GPM) and the pressure distribution of the wave front, a phase geometric propagation model (PGPM) is proposed. The phase distribution of a spherical projectile impacting a thin plate is obtained by theoretical methods. The accuracy of the PGPM is subsequently validated through a comparison of its results with those obtained from numerical simulations.
{"title":"Phase geometric propagation model of spherical projectile impacting thin plate based on shock wave propagation","authors":"Lvtan Chen , Qiguang He , Chenyang Wu , Ying Chen , Qunyi Tang , Xiaowei Chen","doi":"10.1016/j.dt.2025.09.034","DOIUrl":"10.1016/j.dt.2025.09.034","url":null,"abstract":"<div><div>Material phase-transition represents a significant phenomenon and mechanism in the context of hypervelocity protection. This study presents a thorough analysis of the phase-transition phenomena induced by shock pressure as the shock wave propagates initially to the rear of the projectile. The shock wave that induces a phase-transition is commonly referred to as a macroscopic phase-transition wave, whereas the interface that separates the distinct phases is referred to as macroscopic phase-boundary. The contact interface between the spherical projectile and the thin plate, characterized by its curved surface, plays a significant role in the nonlinear propagation and evolution of wave systems. The pressure distribution along the central axis of a spherical projectile is derived in accordance with the linear decay law observed for axial pressure. On this basis, a quadratic function is employed to characterize the trend of changes in wave front pressure, thereby facilitating the establishment of a model for wave front pressure distribution. Using the phase-transition pressure criterion for materials, the wave front phase evolution process is derived, and the macroscopic phase-boundary is determined. Based on the geometric propagation model (GPM) and the pressure distribution of the wave front, a phase geometric propagation model (PGPM) is proposed. The phase distribution of a spherical projectile impacting a thin plate is obtained by theoretical methods. The accuracy of the PGPM is subsequently validated through a comparison of its results with those obtained from numerical simulations.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 14-31"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116687","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.012
Shenhe Zhang , Zhifan Zhang , Shuxin Yang , Longkan Wang , Yutong Sui , Guiyong Zhang , Zhi Zong
In order to investigate the penetration performance of Linear-Shaped Charge (LSC), Embowed Linear-Shaped Charge (ELSC), and Embowed Linear Explosively Formed Projectile (ELEFP) on T-shaped stiffened plates, a series of near-field air-burst experiments are conducted. The damage modes and characteristics of the target plates are compared and analyzed. Each flat plate section is completely punctured, resulting in a penetration hole. The damage modes induced by the three charge types on the stiffened plate structure are consistent, characterized by shear failure in the central region of the flat plate due to penetration by the penetrator, localized plastic deformation of the flat plate, and local penetration failure resulting from partial perforation of the central stiffener. The penetration lengths caused by ELSC and ELEFP are 45.1% and 46.1% larger than that of LSC, while the half-width of the penetration hole generated by ELEFP is 54.2% and 24.7% smaller than that of ELSC and LSC, respectively. The penetration height caused by ELEFP are 17.5% and 62.1% larger than that of ELSC and LSC, respectively. The stiffener effectively segments the damage area, enhancing the local structural strength and limiting the extent of plastic deformation in the flat plate section. The comparative results show that the ELSC proves to be more effective for efficient large-scale damage, and ELEFP is more suitable for achieving efficient localized damage.
{"title":"Experimental study on damage characteristics of t-shaped stiffened plates subjected to different types of shaped charges: Linear-shaped charge, embowed linear-shaped charge, and embowed linear explosively formed projectile","authors":"Shenhe Zhang , Zhifan Zhang , Shuxin Yang , Longkan Wang , Yutong Sui , Guiyong Zhang , Zhi Zong","doi":"10.1016/j.dt.2025.09.012","DOIUrl":"10.1016/j.dt.2025.09.012","url":null,"abstract":"<div><div>In order to investigate the penetration performance of Linear-Shaped Charge (LSC), Embowed Linear-Shaped Charge (ELSC), and Embowed Linear Explosively Formed Projectile (ELEFP) on T-shaped stiffened plates, a series of near-field air-burst experiments are conducted. The damage modes and characteristics of the target plates are compared and analyzed. Each flat plate section is completely punctured, resulting in a penetration hole. The damage modes induced by the three charge types on the stiffened plate structure are consistent, characterized by shear failure in the central region of the flat plate due to penetration by the penetrator, localized plastic deformation of the flat plate, and local penetration failure resulting from partial perforation of the central stiffener. The penetration lengths caused by ELSC and ELEFP are 45.1% and 46.1% larger than that of LSC, while the half-width of the penetration hole generated by ELEFP is 54.2% and 24.7% smaller than that of ELSC and LSC, respectively. The penetration height caused by ELEFP are 17.5% and 62.1% larger than that of ELSC and LSC, respectively. The stiffener effectively segments the damage area, enhancing the local structural strength and limiting the extent of plastic deformation in the flat plate section. The comparative results show that the ELSC proves to be more effective for efficient large-scale damage, and ELEFP is more suitable for achieving efficient localized damage.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 231-243"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116741","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 : 2026-02-01DOI: 10.1016/j.dt.2025.08.013
Xianju Wu , Zhijun Wei , Yun Wang , Ling zhou , Yunhui Wang , Ningfei Wang
This study investigates the performance boundaries of ramjet and scramjet engines fueled by boron-based propellant through full-scale engine modeling and three-dimensional computational fluid dynamics simulations. Results show that the performance boundary between ramjets and scramjets occurs near Mach 7. Specifically, at Mach 6, the ramjet exhibits a 1290 m/s higher specific impulse than the scramjet; however, at Mach 7, their performance becomes comparable. The ramjet's higher static temperature promotes boron particle vaporization and B2O2 dissociation, limiting the total temperature increase, unlike in scramjets. The boron vapor mass fraction significantly impacts this temperature difference, with ramjets exhibiting values 8.5 and 3.9 times higher than scramjets at Mach 6 and Mach 7, respectively. Despite lower total temperatures, ramjets achieve more efficient boron combustion due to the combined effects of higher pressures and longer particle residence times. These findings offer valuable insights for engine designers in selecting ramjet or scramjet configurations for boron-fueled propulsion systems.
{"title":"Performance comparison of full-scale ramjet and scramjet using boron-based propellant","authors":"Xianju Wu , Zhijun Wei , Yun Wang , Ling zhou , Yunhui Wang , Ningfei Wang","doi":"10.1016/j.dt.2025.08.013","DOIUrl":"10.1016/j.dt.2025.08.013","url":null,"abstract":"<div><div>This study investigates the performance boundaries of ramjet and scramjet engines fueled by boron-based propellant through full-scale engine modeling and three-dimensional computational fluid dynamics simulations. Results show that the performance boundary between ramjets and scramjets occurs near Mach 7. Specifically, at Mach 6, the ramjet exhibits a 1290 m/s higher specific impulse than the scramjet; however, at Mach 7, their performance becomes comparable. The ramjet's higher static temperature promotes boron particle vaporization and B<sub>2</sub>O<sub>2</sub> dissociation, limiting the total temperature increase, unlike in scramjets. The boron vapor mass fraction significantly impacts this temperature difference, with ramjets exhibiting values 8.5 and 3.9 times higher than scramjets at Mach 6 and Mach 7, respectively. Despite lower total temperatures, ramjets achieve more efficient boron combustion due to the combined effects of higher pressures and longer particle residence times. These findings offer valuable insights for engine designers in selecting ramjet or scramjet configurations for boron-fueled propulsion systems.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 206-217"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116739","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.028
Yuejie Cao , Xiaoyan Tang , Xiang Li , Zhonghuan Huang , Wenjie Yin , Xiangyu Huang , Hongtu Zhang , Zengqiang Cao
This study introduces electromagnetic dynamic self-piercing riveting (ED-SPR), an innovative technique that integrates electromagnetic riveting principles with static self-piercing riveting (S-SPR) for high-performance structural joints. A dedicated methodology and experimental apparatus for ED-SPR were systematically designed and validated. Quantitative comparative analyses between ED-SPR and S-SPR were conducted on three critical material combinations: CFRP/Al, low-strength steel HC340LA/Al, and high-strength steel DP590/Al. Key findings demonstrate that the electromagnetic-driven process reduces installation resistance by 60% and achieves a 30% larger interlock distance at the joint base compared to S-SPR. These quantitative advantages directly contribute to an approximately 30% increase in load-bearing capacity and superior damage tolerance in ED-SPR joints, as evidenced by tensile-shear testing of single-lap joints. Furthermore, distinct failure modes were observed: ED-SPR joints exhibited top plate pull-out failure in CFRP/Al and DP590/Al configurations, contrasting with the predominant rivet pull-out failure in S-SPR counterparts. Surface morphology and damage evolution were characterized via scanning electron microscopy (SEM) on post-assembly and tensile-failed specimens. The study establishes a foundation for optimizing electromagnetic-driven riveting parameters to mitigate CFRP delamination and further enhance joint reliability in vehicle body and aircraft fuselage structures.
{"title":"Electromagnetic dynamic self-piercing riveting (ED-SPR): A novel approach for enhanced dissimilar material joining","authors":"Yuejie Cao , Xiaoyan Tang , Xiang Li , Zhonghuan Huang , Wenjie Yin , Xiangyu Huang , Hongtu Zhang , Zengqiang Cao","doi":"10.1016/j.dt.2025.09.028","DOIUrl":"10.1016/j.dt.2025.09.028","url":null,"abstract":"<div><div>This study introduces electromagnetic dynamic self-piercing riveting (ED-SPR), an innovative technique that integrates electromagnetic riveting principles with static self-piercing riveting (S-SPR) for high-performance structural joints. A dedicated methodology and experimental apparatus for ED-SPR were systematically designed and validated. Quantitative comparative analyses between ED-SPR and S-SPR were conducted on three critical material combinations: CFRP/Al, low-strength steel HC340LA/Al, and high-strength steel DP590/Al. Key findings demonstrate that the electromagnetic-driven process reduces installation resistance by 60% and achieves a 30% larger interlock distance at the joint base compared to S-SPR. These quantitative advantages directly contribute to an approximately 30% increase in load-bearing capacity and superior damage tolerance in ED-SPR joints, as evidenced by tensile-shear testing of single-lap joints. Furthermore, distinct failure modes were observed: ED-SPR joints exhibited top plate pull-out failure in CFRP/Al and DP590/Al configurations, contrasting with the predominant rivet pull-out failure in S-SPR counterparts. Surface morphology and damage evolution were characterized via scanning electron microscopy (SEM) on post-assembly and tensile-failed specimens. The study establishes a foundation for optimizing electromagnetic-driven riveting parameters to mitigate CFRP delamination and further enhance joint reliability in vehicle body and aircraft fuselage structures.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 218-230"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116740","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.016
Siwei Zhao , Yi Zeng , Xuewen Zhou , Weixing Zhao , Botao Xie , Jianbin Jing , Yan Chen , Yilun Liu
Hypervelocity rocket sled systems are critical for testing advanced military technologies, yet track damage at speeds exceeding Mach 5 remains a significant challenge for system reliability and performance. In this study, we investigated the hypervelocity impact response and protection for high-strength U71Mn or bainitic steel used in rocket sled tracks. Flyer plate impact experiments using a two-stage light-gas gun were conducted to study the hypervelocity collision response, followed by the microstructural characterization via optical microscope, scanning electron microscopy equipped with electron backscatter diffraction to reveal underlying damage mechanisms. Then, the calibrated thermal-mechanical coupled finite element simulations using the Johnson-Cook constitutive model and Mie-Grüneisen equation of state were carried out. Results indicated that bainitic steel exhibits superior impact resistance with predominantly smooth scratch-dominated damage due to its higher ductility. In contrast, U71Mn suffered significant material spallation and crack propagation arising from brittle fracture mechanisms. Zinc-rich epoxy primer coatings effectively mitigated stress concentration and temperature rise in the substrate at impacting velocities below 2.4 km/s, so as to suppress the microstructural damage such as adiabatic shear bands and dynamic recrystallization. However, coating protection diminished at ultra-high-speed impacts due to the coating failure. Dimensional analysis established quantitative relationships of the gouge damage size to projectile mass, impact velocity, and material yield strength. This study provides in-depth insights into damage mechanisms in hypervelocity rail systems, demonstrating that bainitic steel combined with protective coatings can significantly enhance impact resistance and system reliability, offering valuable guidance for the design and optimization of hypervelocity testing platforms.
超高速火箭滑橇系统对于测试先进的军事技术至关重要，然而，超过5马赫的速度对系统可靠性和性能来说仍然是一个重大挑战。本文研究了高强度U71Mn和贝氏体钢用于火箭滑轨的超高速冲击响应和防护性能。利用两级光气枪对飞片进行了超高速撞击实验，并利用光学显微镜、扫描电镜和电子背散射衍射技术对飞片进行了微观结构表征，揭示了飞片的损伤机理。然后，采用Johnson-Cook本构模型和mie - gr neisen状态方程进行了标定后的热-力耦合有限元模拟。结果表明，贝氏体钢具有较高的延展性，具有较好的抗冲击性能，损伤以光滑划痕为主。相比之下，U71Mn由于脆性断裂机制出现了明显的材料剥落和裂纹扩展。富锌环氧底漆能有效减缓冲击速度低于2.4 km/s时基体中的应力集中和温升，从而抑制绝热剪切带和动态再结晶等微观组织损伤。然而，由于涂层失效，涂层保护在超高速撞击下减弱。量纲分析建立了凿击损伤尺寸与弹丸质量、冲击速度和材料屈服强度之间的定量关系。本研究深入探讨了超高速轨道系统的损伤机理，表明贝氏体钢结合防护涂层可显著提高系统的抗冲击性和可靠性，为超高速试验平台的设计和优化提供了有价值的指导。
{"title":"Hypervelocity impact response and protection for the track steels of rocket sled system via light-gas gun experiments","authors":"Siwei Zhao , Yi Zeng , Xuewen Zhou , Weixing Zhao , Botao Xie , Jianbin Jing , Yan Chen , Yilun Liu","doi":"10.1016/j.dt.2025.09.016","DOIUrl":"10.1016/j.dt.2025.09.016","url":null,"abstract":"<div><div>Hypervelocity rocket sled systems are critical for testing advanced military technologies, yet track damage at speeds exceeding Mach 5 remains a significant challenge for system reliability and performance. In this study, we investigated the hypervelocity impact response and protection for high-strength U71Mn or bainitic steel used in rocket sled tracks. Flyer plate impact experiments using a two-stage light-gas gun were conducted to study the hypervelocity collision response, followed by the microstructural characterization via optical microscope, scanning electron microscopy equipped with electron backscatter diffraction to reveal underlying damage mechanisms. Then, the calibrated thermal-mechanical coupled finite element simulations using the Johnson-Cook constitutive model and Mie-Grüneisen equation of state were carried out. Results indicated that bainitic steel exhibits superior impact resistance with predominantly smooth scratch-dominated damage due to its higher ductility. In contrast, U71Mn suffered significant material spallation and crack propagation arising from brittle fracture mechanisms. Zinc-rich epoxy primer coatings effectively mitigated stress concentration and temperature rise in the substrate at impacting velocities below 2.4 km/s, so as to suppress the microstructural damage such as adiabatic shear bands and dynamic recrystallization. However, coating protection diminished at ultra-high-speed impacts due to the coating failure. Dimensional analysis established quantitative relationships of the gouge damage size to projectile mass, impact velocity, and material yield strength. This study provides in-depth insights into damage mechanisms in hypervelocity rail systems, demonstrating that bainitic steel combined with protective coatings can significantly enhance impact resistance and system reliability, offering valuable guidance for the design and optimization of hypervelocity testing platforms.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 282-293"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116789","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 : 2026-02-01DOI: 10.1016/j.dt.2025.09.023
Liang Ma , Lingxin Hu , Haoxiang Wang , Yichao Yuan , Jian Wei , Xiaoxin Zhao , Kunkun Zeng , Yuze Zhao , Zhiyin Zhao , Jiagui Liu , Shizhao Chen , Jinling Gao
High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts, which significantly affected their ballistic limits. In this paper, a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed. To begin with, in order to measure the extremely low stress and strain in small specimens, the conventional Hopkinson bar was reduced to the hundred-micron scale, thereby achieving wave impedance matching with single fibers. In addition, tangential and normal laser Doppler velocimetry (LDV) methods were employed to realize non-contact, high-precision, and high-speed axial velocity measurements of micron-scale incident and transmission bars, respectively. Meanwhile, a microscopic observation system was used to facilitate the installation of miniature fiber samples. The experimental setup and procedures were introduced, and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory. Dynamic compression experiments on Graphene-UHMWPE fibers were carried out, followed by post-compression microstructural characterization via scanning electron microscopy (SEM). Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 105, an order of magnitude higher than the previously reported maximum rates. Furthermore, during the loading process, the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects. This method offers a novel approach for dynamic mechanical characterization of microscale single fibers, enabling the development of comprehensive strain-rate-dependent material models to guide the design of advanced composites and high-performance fibers.
{"title":"Characterization of ultrahigh-strain-rate compressive behaviors in single 10-μm scale fibers using a micro-scale Hopkinson bar method","authors":"Liang Ma , Lingxin Hu , Haoxiang Wang , Yichao Yuan , Jian Wei , Xiaoxin Zhao , Kunkun Zeng , Yuze Zhao , Zhiyin Zhao , Jiagui Liu , Shizhao Chen , Jinling Gao","doi":"10.1016/j.dt.2025.09.023","DOIUrl":"10.1016/j.dt.2025.09.023","url":null,"abstract":"<div><div>High-performance fiber fabrics and composites experienced transverse compression deformation at ultrahigh strain rates near the impact point when subjected to high-velocity impacts, which significantly affected their ballistic limits. In this paper, a fiber-scale experimental method for characterizing ultrahigh strain-rate transverse compression behavior was proposed. To begin with, in order to measure the extremely low stress and strain in small specimens, the conventional Hopkinson bar was reduced to the hundred-micron scale, thereby achieving wave impedance matching with single fibers. In addition, tangential and normal laser Doppler velocimetry (LDV) methods were employed to realize non-contact, high-precision, and high-speed axial velocity measurements of micron-scale incident and transmission bars, respectively. Meanwhile, a microscopic observation system was used to facilitate the installation of miniature fiber samples. The experimental setup and procedures were introduced, and the system accuracy was verified through sample-free loading tests based on one-dimensional stress wave propagation theory. Dynamic compression experiments on Graphene-UHMWPE fibers were carried out, followed by post-compression microstructural characterization via scanning electron microscopy (SEM). Results demonstrated that successful mechanical characterization was achieved at strain rates exceeding 10<sup>5</sup>, an order of magnitude higher than the previously reported maximum rates. Furthermore, during the loading process, the fibers underwent uniform compression deformation while exhibiting pronounced strain-rate effects. This method offers a novel approach for dynamic mechanical characterization of microscale single fibers, enabling the development of comprehensive strain-rate-dependent material models to guide the design of advanced composites and high-performance fibers.</div></div>","PeriodicalId":58209,"journal":{"name":"Defence Technology(防务技术)","volume":"56 ","pages":"Pages 270-281"},"PeriodicalIF":5.9,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146116790","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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