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Experimental study of 3D printed carbon fibre sandwich structures for lightweight applications

Defence technology（防务技术） 2024年第6期36卷 71-77页

作者： Solaiprakash Vellaisamy Raguraman Munusamy Department of Mechanical Engineering Indian Institute of Information Technology Design and ManufacturingKancheepuramChennai600127India School of Interdisciplinary Design and Innovation Indian Institute of Information Technology Design and ManufacturingKancheepuramChennai600127India

Honeycomb sandwich structures are widely used in lightweight ***,these structures are subjected to extreme loading conditions,leading to potential failures due to delamination and debonding between the face sheet and the honeycomb ***,the present study is focused on the mechanical characterisation of honeycomb sandwich structures fabricated using advanced 3D printing *** continuous carbon fibres and ONYX-FR matrix materials have been used as raw materials for 3D printing of the specimens needed for various mechanical characterization testing;ONYX-FR is a commercial trade name for flame retardant short carbon fibre filled nylon filaments,used as a reinforcing material in Morkforged 3D *** and flatwise compression tests have been conducted for different configurations of honeycomb sandwich structures,fabricated by varying the face sheet thickness and core cell size,while keeping the core cell thickness and core height *** on these tests,the proposed structure with face sheet thickness of 3.2 mm and a core cell size of 12.7 mm exhibited the highest energy absorption and prevented delamination and debonding ***,3D printing technology can also be considered as an alternative method for sandwich structure ***,detailed parametric studies still need to be conducted to meet various other structural integrity criteria related to the lightweight applications.

关键词： 3D printed composite Honeycomb sandwich Edgewise compression Flatwise compression Lightweight

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FUNDAMENTAL STUDY ON MACHINE LEARNING MODEL FOR RC BEAM SUBJECTED TO SEVERAL LOADING AND CRACK REPAIR

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AIJ Journal of technology and design 2025年第77期31卷 240-245页

作者： Matsubayashi, Miki Sugawara, Sota Nakamura, Mizuki Takase, Yuya Division of Engineering Muroran Institute of Technology Japan Division of Sustainable and Environmental Engineering Muroran Institute of Technology Japan College of Design and Manufacturing Technology Muroran Institute of Technology Japan

Japan is prone to large earthquakes. Therefore, buildings may be subjected to multiple seismic loads. In this study, the RC cantilever specimens were subjected to shear loads three times. As the results of the test, as the number of loads increased, the crack width opened;and the stiffness decreased without repair. However, with crack repair, the crack width became small;and the stiffness recovered slightly. In addition, the machine learning model were constructed;and then it could reasonably estimate the envelope curves. © 2025 Architectural institute of Japan. All rights reserved.

关键词： Repair

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Numerical study on ignition start-up process of an underwater solid rocket motor across a wide depth range

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Chinese Journal of Aeronautics 2024年第10期37卷 136-157页

作者： Deyou WANG Shipeng LI Ge JIN Ruyao WANG Dian GUAN Ningfei WANG School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing System Design Institute of Electro-mechanic Engineering Beijing 100854China

Solid rocket motors have important applications in the propulsion of trans-media vehicles and underwater launched *** this paper,the ignition start-up process of an underwater solid rocket motor across a wide depth range has been numerically studied.A novel multi-domain integrated model has been developed by combining the solid propellant ignition and combustion model with the volume of fluid multiphase *** integrated model enables the coupled simulation of the propellant combustion and gas flow inside the motor,along with the gas jet evolution in the external water *** detailed flow field developments in the combustion chamber,nozzle,and wake field are carefully *** variation rules of the internal ballistics and thrust performance are also *** effects of environmental medium and operating depth on the ignition start-up process are systematically *** results show that the influence of the operating environment on the internal ballistic characteristics is primarily reflected in the initial period after the nozzle closure *** development of the gas jet in water lags significantly compared with that in *** the water depth increases,the ignition delay time of the motor is shortened,and the morphology evolution of the gas jet is significantly compressed and ***,the necking and bulging of the jet boundary near the nozzle outlet and the consequent shock oscillations are intensified,resulting in stronger fluctuations in the wake pressure field and motor thrust.

关键词： Underwater propulsion Solid rocket motor Ignition start-up process Underwater gas jet Thrust oscillation

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Endo-atmospheric maneuver penetration strategy based on generative adversarial reinforcement learning

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Chinese Journal of Aeronautics 2025年第4期38卷 394-407页

作者： Yaoluo HUI Xiumin LI Chen LIANG Junzheng SUN Zheng DU Beijing System Design Institute of the Electro-mechanic Engineering Beijing 100854China Beijing Institute of Control&Electronics Technology Beijing 100038China

An intelligent endo-atmospheric penetration strategy based on generative adversarialreinforcement learning is proposed in this ***,attack and defense adversarial mod-els are established,and missile maneuver penetration problem is transformed into an optimal con-trol problem,considering penetration,handover position and mid-terminal guidance ***,Radau Pseudospectral method is adopted to generate data samples consideringrandom ***,Generative Adversarial Imitation Learning Combined withDeep Deterministic Policy Gradient method(GAIL-DDPG)is designed,with internal processreward signals constructed to tackle long-term sparse reward in missile manuver penetration ***,penetration strategy is trained and *** shows that using generativeadversarial reinforcement learning,with sample library to learn expert experience in training earlystage,the proposed method can quickly ***,performance is further optimized with rein-forcement learning exploration strategy in the later stage of *** shows that the pro-posed method has better engineering application ability compared with traditional reinforcementlearning method.

关键词： Hypersonic glide vehicle Endo-atmospheric penetration strategy Deep reinforcement learning Guidance GAIL-DDPG

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Microstructure transformations and improving wear resistance of austenitic stainless steel additively fabricated by arc-based DED process

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Defence technology（防务技术） 2024年第8期38卷 194-204页

作者： Ashish Yadav Manu Srivastava Prashant K.Jain Sandeep Rathee Hybrid Additive Manufacturing Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia FFF Laboratory Mechanical Engineering DepartmentPDPM Indian Institute of Information TechnologyDesign&ManufacturingJabalpur482005Madhya PradeshIndia Department of Mechanical Engineering National Institute of TechnologySrinagarIndia

In this study, austenitic stainless steel(ASS) was additively fabricated by an arc-based direct energy deposition(DED) technique. Macrostructure, microstructure, mechanical characteristics at different spatial orientations(0°, 90°, and 45°), and wear characteristics were evaluated at the deposited structure top, middle, and bottom regions. Results show that austenite(γ) and delta-ferrite(δ) phases make up most of the microstructure of additively fabricated SS316LSi steel. Within γ matrix, δ phase is dispersed both(within and along) grain boundaries, exhibiting a fine vermicular morphology. The bottom, middle,and top regions of WAAM deposited ASS exhibit similar values to those of wrought SS316L in the tensile and impact test findings. Notably, a drop in hardness values is observed as build height increases. During SEM examinations of fractured surfaces from tensile specimen, closed dimples were observed, indicating good ductility of as-built structure. Wear test findings show signs of mild oxidation and usual adhesive wear. By depositing a mechanically mixed composite layer, an increase in the oxidation percentage was discovered to facilitate healing of worn surfaces. The findings of this study will help in design, production and renovation of products/components that are prone to wear. WAAM-deposited ASS has remarkable strength and ability to withstand impacts;it can be used in the production of armour plates for defence applications, mainly military vehicles and aircraft.

关键词： Metal additive deposition Defence applications Arc-based DED Characterization Wear behaviour Fractography

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Underwater Directional Acoustic Source Based on Pentamode Material

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Acta Mechanica Solida Sinica 2024年第1期37卷 1-9页

作者： Binghao Zhao Peng Wang Dongwei Wang Gengkai Hu School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Wuhan Second Ship Design and Research Institute Wuhan 430205China

An underwater directional acoustic emitter is conceived with a highly anisotropic lattice material,whose acoustic characteristics manifest strong dependence on the orientation of the lattice material’s principal *** these features,a cylindrical structure made of such anisotropic lattice material is engineered to possess distinct impedance values in different directions,thereby facilitating wave emission along the principal axis while inducing reflection in other ***,through numerical simulations,it is demonstrated that the emission direction can be effectively manipulated by adjusting the principal axis orientation,concurrently enhancing the emitted *** contrast to previous directional acoustic structures,the compact emitter presented in this study can get rid of the size-wavelength constraint,enabling effective control of low-frequency waves.

关键词： Underwater Directional emission Pentamode material Broadband frequency

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Developing a Dynamic Expression Model That Can Simultaneously Control Robot's Facial and Movement Expressions

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Journal of institute of Control, Robotics and Systems 2024年第1期30卷 8-12页

作者： Park, Haeun Lee, Jiyeon Dzhoroev, Temirlan Kim, Byounghern Lee, Hui Sung Department of Creative Design Engineering Ulsan National Institute of Science and Technology Korea Republic of Department of Design Ulsan National Institute of Science and Technology Korea Republic of

Social robots commonly rely on facial expressions and gestures to convey emotions. However, many robots follow a predetermined sequence, executing a set of facial animations and movement sequences once an emotion is identified. This rigid approach can lead to unnatural processing when confronted with additional stimuli during an ongoing emotional expression. This may cause the robot to ignore the new stimulus until the emotion is fully expressed, or to abruptly move on to the next one. To address this limitation, we implemented an emotion engine with a linear dynamic affect-expression model (LDAEM) that calculates the emotion based on stimuli and determines the corresponding facial expression and robot movements. By leveraging the Ekman 6 basic emotions, our emotion engine incorporates 12 control points (CPs) for facial expression and 3 CPs for movement. Experimental results demonstrate the dynamic adaptation of emotions to stimuli. Notably, our approach allows for smooth transitions between emotions, even when different emotional stimuli are introduced during an ongoing emotional expression. Moreover, it can be seamlessly applied to other robotic systems, offering a versatile framework for emotional expression. © ICROS 2024.

关键词： Human robot interaction

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Ballistic response of skin simulant against fragment simulating projectiles

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Defence technology（防务技术） 2023年第12期30卷 70-82页

作者： Punit Kumar Pandey Atul Harmukh M.K.Khan M.A.Iqbal S.G.Ganpule Department of Mechanical and Industrial Engineering Indian Institute of Technology Roorkee247667India Department of Civil Engineering Indian Institute of Technology Roorkee247667India Department of Design Indian Institute of Technology Roorkee247667India

The response of biological phantoms against high velocity impact is actively sought for applications in defense,space,soft robotics and *** this end,we study the ballistic response of silicone based skin simulant against fragment *** a pneumatic gas gun setup,six chisel-nosed and three regular shaped(sphere,cylinder,and cube)fragments were impacted on the skin *** resulting skin simulant response was studied in terms of ballistic limit velocities,energy densities,failure pattern,and the mechanics of *** results indicate that the shape of the fragment affects the ballistic limit *** ballistic limit velocities,energy densities of the chisel-nosed fragment simulating projectiles were relatively insensitive to the size(mass),except for the smallest(0.16 g)and largest(2.79 g)chisel-nosed *** the same size(1 g),ballistic limit velocities and failure are dependent on the shape of the *** skin simulant failed by combined plugging and elastic hole *** in the spherical fragment was dominated by the elastic hole enlargement,whereas plugging failure was dominant in all other *** spherical,cylindrical,and chisel-nosed fragments created circular cavities,and the cubical fragment created a square *** the case of the spherical fragment,slipping of the fragment within the skin simulant was *** fragments created lateral cracks emanating from the corners of the square ***,for all the fragments,the maximum deformation corresponding to the perforation was lower than the non-perforation indicating rate dependent,stress driven *** maximum deformation was also dependent on the shape of the ***,these results provide unique insights into the mechanical response of a soft simulant against ballistic *** have utility in the calibration and validation of computational models,design of personal protective equipment,and antipersonnel syste

关键词： Skin simulant Fragment Impact Ballistic limit velocity Energy density Failure

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Compensation modification of plastic gear tooth profile considering meshing deformation

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Frontiers of Mechanical engineering 2024年第5期19卷 111-128页

作者： Mingyong LIU Yaole SONG Xinguang HAN Jun HU Chunai YAN Hubei Agricultural Machinery Engineering Research and Design Institute Hubei University of TechnologyWuhan 430068China Intelligent Manufacturing Institute Wuchang Institute of TechnologyWuhan 430065China

The plastic gear is widely used in agricultural equipment,electronic products,aircraft,and other fields because of its light weight,corrosion resistance,and self-lubrication ***,it has a limited range of working conditions due to the low modulus and thermal deformation of the material,especially in high-speed and heavy-duty situations.A compensation modification method(CMM)is proposed in this paper to restrain the heat production of the plastic gear tooth surface by considering the meshing deformation,and the corresponding modification formulas are *** the position of the maximum contact pressure(CP)and the relative sliding velocity(RSV)of the tooth surface resulted in a 30%lower steady-state temperature rise of the modified plastic gear tooth surface than that of the unmodified plastic ***,the temperature rise of plastic gear with CMM is reduced by 19%compared with the traditional modification of removal ***,the influences of modification index and the segment number of modification on the meshing characteristics of plastic gear with CMM are discussed,such as maximum CP and steadystate temperature rise,RSV,transmission error,meshing angle,and contact ratio.A smaller segment number and modification index are beneficial to reduce the temperature rise of plastic gear with ***,an experiment is carried out to verify the theoretical analysis model.

关键词： plastic gear compensation modification meshing deformation temperature rise tooth profile

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Joint Rain Streaks & Haze Removal Network for Object Detection

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Computers, Materials & Continua 2024年第6期79卷 4683-4702页

作者： Ragini Thatikonda Prakash Kodali Ramalingaswamy Cheruku Eswaramoorthy K.V Department of Electronics and Communication Engineering National Institute of TechnologyWarangal506004India Department of Computer Science and Engineering National Institute of TechnologyWarangal506004India Department of Electronics and Communication Engineering Indian Institute of Information TechnologyDesign and ManufacturingKurnool518008India

In the realm of low-level vision tasks,such as image deraining and dehazing,restoring images distorted by adverse weather conditions remains a significant *** emergence of abundant computational resources has driven the dominance of deep Convolutional Neural Networks(CNNs),supplanting traditional methods reliant on prior ***,the evolution of CNN architectures has tended towards increasing complexity,utilizing intricate structures to enhance performance,often at the expense of computational *** response,we propose the Selective Kernel Dense Residual M-shaped Network(SKDRMNet),a flexible solution adept at balancing computational efficiency with network accuracy.A key innovation is the incorporation of an M-shaped hierarchical structure,derived from the U-Net framework as M-Network(M-Net),within which the Selective Kernel Dense Residual Module(SDRM)is introduced to reinforce multi-scale semantic feature *** methodology employs two sampling techniques-bilinear and pixel unshuffled and utilizes a multi-scale feature fusion approach to distil more robust spatial feature map *** the reconstruction phase,feature maps of varying resolutions are seamlessly integrated,and the extracted features are effectively merged using the Selective Kernel Fusion Module(SKFM).Empirical results demonstrate the comprehensive superiority of SKDRMNet across both synthetic and real rain and haze datasets.

关键词： Image deraining Selective Dense Residual Module(SDRM) Selective Kernel Fusion Module(SKFM) Selective KernelDense Residual M-Shaped Network(SKDRMNet)

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