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Design and dynamic analysis of a scissors hoop-rib truss deployable antenna mechanism

Defence technology（防务技术） 2023年第6期24卷 399-413页

作者： Bo Han Xiangkun Li Jian Sun Yundou Xu Jiantao Yao Yongsheng Zhao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao066004China Key Laboratory of Advanced Forging&Stamping Technology and Science Ministry of Education of ChinaYanshan UniversityQinhuangdao066004China

As the support mechanism of space-borne antennas,space deployable antenna mechanism belongs to complex multi-closed-loop coupling mechanism,configuration design and dynamic analysis are more difficult than general parallel *** this paper,an unequal-length scissors mechanism(ULSM)is proposed by changing the position of the internal rotational joint through a basic scissors mechanism.A scissors hoop-rib truss deployable antenna mechanism(SHRTDAM)is constructed by replacing the parabolic rib with the *** analysis of SHRTDAM is conducted,and the degree of freedom(DOF)of the whole antenna mechanism is analyzed based on screw theory,the result showed that it has only one *** and acceleration characteristics of SHRTDAM are obtained by the screw derivative and rotation *** on Lagrange equation,dynamic model of this mechanism is established,the torque required to drive the mechanism is simulated and verified by Adams and MATLAB *** addition,a ground experiment prototype of 1.5-m diameter was fabricated and a deployment test is conducted,which demonstrated the mobility and deployment performance of the whole *** mechanism proposed in this paper can provide a good reference for the design and analysis of large aperture space deployable antennas.

关键词： Scissors mechanism Deployable antenna Screw theory Kinematic analysis Dynamic analysis

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Effect of Pulse Current on Interface Microstructure and Bonding Properties of TA1/304 Double-Layer Clad plates

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Chinese Journal of Mechanical Engineering 2024年第5期37卷 272-287页

作者： Xiongwei Guo Zhongkai Ren Pengjie Zhang Chao Zhang Shuyong Jiang Qi Zhang Tao Wang Qingxue Huang College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of EducationTaiyuan University of TechnologyTaiyuan 030024China National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan 030024China China-Australia Joint Research Center of Taiyuan University of Technology Taiyuan 030024China

It is difficult to effectively improve the low bonding strength of TA1/304 clad *** study proposes a new process for applying pulse current(1500 A,500 Hz,50%duty cycle)to TA1/304 clad plates during the rolling process,which changes the interface microstructure and effectively improves the bonding strength of the clad *** influence of the pulsed current on the interface microstructure and bonding strength was systematically *** results indicate that the clad plate is initially bonded at 750℃ and 35%reduction ratio under electrically-assisted rolling(EAR),and finally the higher bonding strength is obtained at 850℃ and 48%reduction ratio,reaching 395 *** strengthening of the interface element diffusion and grain refinement under the action of the pulsed current are important reasons for the improvement in the bonding strength of the clad *** discovery provides new ideas for the preparation of clad plates with high bonding performance.

关键词： TA1/304 clad plates Electrically-assisted rolling(EAR) Element diffusion Microstructure Tensile shear strength

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Coordinated Regulation of Bonding Interfacial Structure and Mechanical Properties of Al/Mg Alloy Composite Plates by Electrically Assisted Rolling

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Chinese Journal of Mechanical Engineering 2025年第1期38卷 246-260页

作者： Tingting Zhang Xingrun An Yan Wang Gongbo Bian Tao Wang College of Mechanical and Vehicle Engineering Taiyuan University of TechnologyTaiyuan 030024China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment of Ministry of Education Taiyuan University of TechnologyTaiyuan 030024China National Key Laboratory of Metal Forming Technology and Heavy Equipment Taiyuan University of TechnologyTaiyuan 030024China College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China.

Current research on the fabrication of rolled composite plates primarily focuses on processing and bonding *** with hot-rolling technology,the electrically assisted rolling process has demonstrated excellent performance in interfacial bonding ***,the influence of different current loading modes on the interfacial recombination process of composite panels varies *** this study,low-frequency electrically assisted rolling was used in the first pass to pre-bond a composite plate at a low reduction rate of 15%.High-frequency electrically assisted rolling was used during the second pass,and Al/Mg alloy composite plates were *** interfacial microstructure and mechanical properties of the composite plate were coordinated regulation by designing the rolling reduction *** results showed the interfacial morphology of the alternating distribution of the melt-diffusion layer,diffusion layer,and the formation of a new Al/Mg bonding *** the melt-diffusion interface,the irregular intermetallic compounds(IMCs)and the new Al/Mg bonding interface were alternately distributed,and the IMCs contained theα-Mg,Mg17Al12,and Mg2Al3 *** addition,an extremely high shear strength of 78.26 MPa was *** of the Mg alloy matrix was observed on the fracture surface of the Al alloy *** high shear strength was mainly attributed to the formation of a unique interfacial structure and the appearance of a melt-diffusion *** to the diffusion-reduction interface,the regular rectangular IMCs and the new Al/Mg bonding interface were alternately distributed,and the IMCs consisted of the Mg17Al12 and Mg2Al3 *** shear test results showed that the shear strength of the interface reached 68.69 MPa,and a regular distribution of the Mg alloy matrix with dimples and the Al alloy matrix with a necking zone was observed on the fracture surface of the Al *** strength test results revealed a maximum value of

关键词： Al/Mg alloy composite plate Electrically assisted rolling Bonding properties Interfacial structure

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Force Analysis of the Overconstrained Mechanisms Based on Equivalent Stiffness Considering Limb Axial Deformation

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 292-304页

作者： Jinwei Guo Yongsheng Zhao Bo Chen Guoxing Zhang Yundou Xu Jiantao Yao Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan UniversityQinhuangdao066004China Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of National Education Yanshan UniversityQinhuangdao066004China

Overconstrained mechanism has the advantages of large bearing capacity and high motion reliability,but its force analysis is complex and difficult because the mechanism system contains *** the limb axial deformation,taking typical 2SS+P and 7-SS passive overconstrained mechanisms,2SPS+P and 7-SPS active overconstrained mechanisms,and 2SPS+P and 7-SPS passive-input overconstrained mechanisms as examples,a new force analysis method based on the idea of equivalent stiffness is *** equivalent stiffness matrix of passive overconstrained mechanism is derived by combining the force balance and deformation compatibility equations with consideration of axial elastic limb *** relationship between the constraint wrench magnitudes and the external force,limb stiffness is *** equivalent stiffness matrix of active overconstrained mechanism is derived by combining the force balance and displacement compatibility ***,the relationship between the magnitudes of the actuated wrenches and the external force,limb stiffness is *** with the equivalent stiffness of the passive overconstrained mechanism,an analytical relationship between the actuated forces of passive-input overconstrained mechanism and the output displacement,limb stiffness is ***,adaptability of the equivalent stiffness to overconstrained mechanisms is discussed,and the effect of the limb stiffness on overconstrained mechanisms force distribution is *** research results provide a theoretical reference for the design,research and practical application of overconstrained mechanism.

关键词： Active overconstrained Passive overconstrained Passive-input overconstrained Equivalent stiffness Force distribution

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Data-driven casting defect prediction model for sand casting based on random forest classification algorithm

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China Foundry 2024年第2期21卷 137-146页

作者： Bang Guan Dong-hong Wang Da Shu Shou-qin Zhu Xiao-yuan Ji Bao-de Sun Shanghai Key Lab of Advanced High-Temperature Materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Lab of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai 200240China Hefei Casting and Forging Factory of Anhui Heli Co. LtdHefei 230000China State Key Laboratory of Materials Processing and Die&Mould Technology Huazhong University of Science and TechnologyWuhan 430074China

The complex sand-casting process combined with the interactions between process parameters makes it difficult to control the casting quality,resulting in a high scrap rate.A strategy based on a data-driven model was proposed to reduce casting defects and improve production efficiency,which includes the random forest(RF)classification model,the feature importance analysis,and the process parameters optimization with Monte Carlo *** collected data includes four types of defects and corresponding process parameters were used to construct the RF *** results show a recall rate above 90% for all *** Gini Index was used to assess the importance of the process parameters in the formation of various defects in the RF ***,the classification model was applied to different production conditions for quality *** the case of process parameters optimization for gas porosity defects,this model serves as an experimental process in the Monte Carlo method to estimate a better temperature *** prediction model,when applied to the factory,greatly improved the efficiency of defect *** show that the scrap rate decreased from 10.16% to 6.68%.

关键词： sand casting process data-driven method classification model quality prediction feature importance

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An Al–Al interpenetrating-phase composite by 3D printing and hot extrusion

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International Journal of Minerals,Metallurgy and Materials 2023年第4期30卷 678-688页

作者： Yulin Lin Di Wang Chao Yang Weiwen Zhang Zhi Wang School of Mechanical and Automotive Engineering South China University of TechnologyGuangzhou 510640China Guangdong Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of TechnologyGuangzhou 510640China

We report a process route to fabricate an Al–Al interpenetrating-phase composite by combining the Al–Mg–Mn–Sc–Zr lattice structure and Al_(84)Ni_(7)Gd_(6)Co_(3)nanostructured structure. The lattice structure was produced by the selective laser melting and subsequently filled with the Al_(84)Ni_(7)Gd_(6)Co_(3)amorphous powder, and finally the mixture was used for hot extrusion to produce bulk samples. The results show that the composites achieve a high densification and good interface bonding due to the element diffusion and plastic deformation during hot *** bulk samples show a heterogeneous structure with a combination of honeycomb lattice structure with an average grain size of less than1 μm and nanostructured area with a high volume fraction of nanometric intermetallics and nanograin α-Al. The heterogeneous structure leads to a bimodal mechanical zone with hard area and soft area giving rise to high strength and acceptable plasticity, where the compressive yield strength and the compressive plasticity can reach ~745 MPa and ~30%, respectively. The high strength can be explained by the rule of mixture,the grain boundary strengthening, and the back stress, while the acceptable plasticity is mainly owing to the confinement effect of the nanostructured area retarding the brittle fracture behavior.

关键词： Al-based composites heterogeneous structure additive manufacturing mechanical properties

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Determination of interfacial heat transfer coefficient at the frozen sand mold casting process of ZL101 alloy

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Journal of Materials Science & technology 2024年第27期194卷 28-42页

作者： Shijie Dong Zhongde Shan Feng Lin Haoqin Yang Xiao Liang Department of Mechanical Engineering Tsinghua UniversityBeijing 100084China State Key Laboratory of Advanced Forming Technology and Equipment China Academy of Machinery Science and TechnologyBeijing 100037China Key Laboratory for Advanced Materials Processing Technology Ministry of Education of ChinaBeijing 100084China College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of Material Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Compared to the resin sand mold casting process, frozen casting is more environmentally friendly, providing a better working environment and enhanced supercooling degree. The interfacial heat transfer coefficient (IHTC) between frozen sand mold and metal is an important parameter that significantly influences the final mechanical properties and microstructure of the castings. This paper solved the inverse heat conduction problem using the finite difference method (FDM). In addition, the conjugate gradient method (CGM) was adopted to calculate the temperature distribution and heat flux in the molten metal. At the same time, the particle swarm optimization algorithm (PSO) was used in temperature distribution determination in frozen sand mold. The interfacial heat transfer coefficient (IHTC) was estimated during the solidification of ZL101. The results showed a good agreement between calculated and experimental data, obtaining accurate casting interface temperature Tm, frozen sand mold interface temperature Ts, heat flux q, and IHTC. The analysis of the IHTC variation revealed a water content value within the range of 4 wt.% to 5 wt.% resulted in IHTC in two types of interpretation, called ‘fluctuation type’ and ‘turning type’.

关键词： Frozen sand mold Interfacial heat transfer coefficient(IHTC) Finite difference method(FDM) Conjugate gradient method(CGM) Particle swarm optimization(PSO)

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Microstructure and mechanical properties stability of pre-hardening treatment in Al-Cu alloys for pre-hardening forming process

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International Journal of Minerals,Metallurgy and Materials 2024年第3期31卷 539-551页

作者： Liping Tang Pengfei Wei Zhili Hu Qiu Pang Hubei Longzhong laboratory Xiangyang 441000China Hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive EngineeringWuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center for Green&Precision Material Forming Wuhan University of TechnologyWuhan 430070China Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education School of Machinery and AutomationWuhan University of Science and TechnologyWuhan 430081China

The stability of the microstructure and mechanical properties of the pre-hardened sheets during the pre-hardening forming(PHF)process directly determines the quality of the formed *** microstructure stability of the pre-hardened sheets was in-vestigated by differential scanning calorimetry(DSC),transmission electron microscopy(TEM),and small angle X-ray scattering(SAXS),while the mechanical properties and formability were analyzed through uniaxial tensile tests and formability *** results in-dicate that the mechanical properties of the pre-hardened alloys exhibited negligible changes after experiencing 1-month natural aging(NA).The deviations of ultimate tensile strength(UTS),yield strength(YS),and sheet formability(Erichsen value)are all less than 2%.Also,after different NA time(from 48 h to 1 month)is applied to alloys before pre-hardening treatment,the pre-hardened alloys possess stable microstructure and mechanical properties as ***,with the extension of NA time before pre-hardening treatment from 48 h to 1 month,the contribution of NA to the pre-hardening treatment is *** a yield strength increment of 20 MPa is achieved,with no loss in *** limited enhancement is mainly attributed to the fact that only a limited number of clusters are transformed into Guinier-Preston(GP)zones at the early stage of pre-hardening treatment,and the formation ofθ''phase inhibits the nucleation and growth of GP zones as the precipitated phase evolves.

关键词： Al-Cu alloy pre-hardened alloy natural aging mechanical properties microstructure

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Dynamic Recrystallization Mechanism and Texture Evolution during Interactive Alternating Extruded Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2023年第8期36卷 1292-1304页

作者： Ronghe Gao Feng Li Huaqiu Du Pengda Huo School of Materials Science and Chemical Engineering Harbin University of Science and TechnologyHarbin150040China Key Laboratory of Advanced Manufacturing and Intelligent Technology Ministry of EducationHarbin University of Science and TechnologyHarbin150080China Heilongjiang Provincial Key Laboratory of Light Metal Materials Modification and Green Forming Technology Harbin150040China

Alternating extrusion(AFE)is a new way to effectively alter the texture and enhance the mechanical properties of the extruded ***,the mechanisms of microstructure evolution and enhancement of hardness are still unknown by different extrusion ratios(ERs)during *** work systematically investigated the microstructure and hardness of AZ31 alloy with various extrusion ratios of 8.1,15.6,and 24.8 by electron backscattered *** most striking result to emerge from the data is that when the ERs were increased from 8.1 to 15.6,the grain size was refined to 7.13μ***,when the ER reached 24.8,the average grain size was 11.43μ*** proportion of recrystallization was only 2.92%,there was a continuous rotation of sub-grains at coarse grain boundaries,and non-basal slipdislocations were activated and enriched near low-angle grain *** present,the recrystallization has not been *** grains of the product are coarsened,and the hardness is ***λ=15.6,the AFE has a significant grain refinement effect and the highest hardness value.

关键词： Alternate extrusion method AZ31 magnesium alloy Extrusion ratio-Grain refinement Hardness

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Disrupting variant selection memory effect in laser powder bed fusion to improve strength-ductility synergy of Ti-6Al-4V alloys

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Journal of Materials Science and technology 2025年 219卷 19-32页

作者： Yang, C. Liu, B. Pan, L.L. Yang, Y. Zhou, Y. Cai, W.S. Liu, Le-hua National Engineering Research Center of Near-net-shape Forming for Metallic Materials Guangdong Provincial Key Laboratory for Processing and Forming of Advanced Metallic Materials South China University of Technology Guangzhou 510640 China Shenzhen Leadwell Technology Co. Ltd. Shenzhen Guangdong 518000 China

Texture formation is frequently observed in parts produced by Laser Powder Bed Fusion (L-PBF), which can induce anisotropy and may potentially degrade plasticity. In this study, we introduce a laser remelting strategy to mitigate these adverse effects. By employing experimental observations and numerical simulations, we established the relationship between melt pool thermal history, variant selection, and mechanical properties. Our results indicate that the strengthening of texture can be prevented by disrupting the variant selection memory effect when there is a difference in scanning speeds between the printing and remelting lasers. The achieved random variant orientation is attributed to the altered cooling rates and temperature gradient directions during solidification across different layers. The optimized Ti-6Al-4V alloy demonstrates high strength (1211.5 ± 13.3 MPa) and significant elongation (12.3 % ± 0.8 %), exhibiting a superior strength-ductility synergy compared to samples produced by direct printing or laser remelting with consistent parameters, as well as most reported L-PBF processed Ti-6Al-4V alloys. Our findings provide new insights into phase transformation kinetics in L-PBF of Ti-6Al-4V alloys and facilitate the optimization of this process for manufacturing high-performance components. © 2024

关键词： Titanium alloys

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