检索结果-内蒙古大学图书馆

SSRN 2023年

作者： Bi, Jiang Dong, Guojiang Zhang, Liping Ma, Shaozhong Zhang, Dongsheng Wang, Ji Li, Wen Xu, Zuo Li, Shide Starostenkov, Mikhail Dmitrievich Yanshan University China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China CITIC Daika Co. Ltd. Qinhuangdao066004 China Hebei Key Laboratory of Special Delivery Equipment Yanshan University Qinhuangdao066004 China State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao066004 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia

The aluminum alloy wheel hub is mainly produced by low-pressure die casting process (LPDC), which casting quality is related to the process parameters. In this paper, the LPDC process of the A356 alloy wheel hub was simulated by ProCAST software, and the forming quality of the wheel hub under different cooling processes has been studied. The result indicated that the liquid aluminum exhibited different solidification characteristics under three cooling processes of 300 L/min for 150 s, 400 L/min for 140 s and 500 L/min for 130 s, and the wheels showed a sequential solidification state under the condition of 400 L/min for 140 s. By comparing the tensile properties of the rim under 300 L/min for 150 s and 400 L/min for 140 s cooling processes, it was found that the latter had higher tensile strength and elongation, which were 178.9 MPa and 6.6%, respectively. The reduction of casting defects, microstructure refinement and uniform distribution of eutectic Si particles in the wheel hub are the main reasons for the improvement of mechanical properties. © 2023, The Authors. All rights reserved.

关键词： Microstructure

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Yield Characteristics Strengthening and Yield Strength Anti-Dispersion Identification Based on Bending Deformation

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Research Square 2020年

作者： Duan, Yong-Chuan Qiao, Hai-Di Zhang, Fang-Fang Liu, Yu Tian, Le Yang, Liu Guan, Ying-Ping Key Laboratory of Advanced Forming & Stamping Technology and Science Ministry of Education of China Yanshan University Hebei Qinhuangdao066004 China College of Mechanical Engineering Yanshan University Hebei Qinhuangdao066004 China

The online derivation of material yield is important for consistency control of product quality. Compare with other deformation, bending deformation is more suitable for online identification. The transition portion of bending force stroke curve is related to the yield strength of material, but for a wide set of materials with different thickness and properties, its longer transition curve shows higher identification scattering. In this paper, the yield characteristics strengthening method and the new anti-dispersion identification method are studied to reduce the scattering. It is found that the yield characteristics are comprehensively affected by several factors. The higher yield strength, together with thinner thickness, can weaken the yield characteristics. The thicker material with wider die span can strengthen the yield characteristics. Window vector method (WV) and standardized fitting residual method (SFR) are proposed. Through the numerical study found that the yield load obtained by WV method shows a most accurate correlation with yield strength. A novel piecewise correlation equation is proposed and added a thickness variable to eliminate partial dispersion from varied thickness. Furthermore, this paper uses the experimental data to extract the generalization error of new correlation model fitted by yield loads from WV method, maximum error is below 12%. This method can improve the accuracy and efficiency of online ranking materials. © 2020, CC BY.

关键词： Yield stress

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Effect of Temperature on the Dispersion of Graphene in Graphene Reinforced Aluminum Matrix Composite

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IOP Conference Series: Materials science and Engineering 2020年第1期774卷

作者： Qiang Wang Qingze Sun Shengyong Chen Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao 066004 China

The influence of hot pressing temperature on the dispersion of graphene (GR) in GR reinforced aluminum matrix composites was investigate. The microstructures of the sample were observed by optical microscope, scanning electron microscopy and energy dispersion spectrum, respectively. The temperature is hold at 640-750°C, and the interval is 10°C. The results show that GR is mainly distributed at the grain boundary at 640 °C. And GR is dispersed in the aluminum matrix, without obvious agglomeration at the temperature from 670 °C to 680 °C. However, GR is agglomerated in the aluminum matrix and has obvious regional differentiation at 690-750 °C, in which the concentrated area of GR is in the middle of the sample, and the dilution area in the rest.

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Precision and Flexible Bending Control strategy Based on Analytical Models and Data Models

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Research Square 2020年

作者： Duan, Yong-Chuan Zhang, Fang-Fang Liu, Yu Qiao, Hai-Di Yang, Liu Guan, Ying-Ping Key Laboratory of Advanced Forming & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao Hebei066004 China College of Mechanical Engineering Yanshan University Qinhuangdao Hebei066004 China

Forming of various customized bending parts, small batches, as well as numerous types of materials is a new challenges for Industry 4.0, the current control strategies can not meet the precision and flexibility requirement, expected control strategy of bending processes need to not only resist unknown interferences of process condition and models, but also produce various new parts automatically and efficiently. In this paper, a precision and flexible bending control strategy based on analytical models and data models is proposed to built adaptive bending systems. New analytical prediction models for loading and unloading are established and suitable for various materials, a sequential identification strategy is proposed to search nominal properties using the four sub-optimization models. A data-based feedback model is established to prevent over-bending and eliminate online deviation. Above models are merged into a precision and flexible control strategy. the system firstly uses sub-optimization models to search the nominal point which is near to target point, secondly the system further uses feedback model to eliminate residual error between the nominal point and target point. Compared with four kinds sheet metals, the allowable ranges for variables are determined for a good convergence. The target bending angles were set to 20°, 40°, and 60°. Forty parts were tracked for each kind material, the adaptive bending system converged after one iteration, and exhibited better performances. © 2020, CC BY.

关键词： Analytical models

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Structural optimization and performance research on the piston pair of low speed high torque water hydraulic motor

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Meitan Xuebao/Journal of the China Coal Society 2013年第SUPPL.2期38卷 536-542页

作者： Wang, Zhi-Qiang Gao, Dian-Rong Huang, Yao Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao 066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao 066004 China

The aim of this paper was to find an optimal configuration to improve the static and dynamic characteristics of the piston pair. Based on the equilibrium equation and the flow equation, the mathematical models of the power loss and the dynamic characteristics were established. The total power loss, the velocity and the displacement of roll ball can be the performance indexes of the piston pair. Different size of the water film thickness has different performance indexes. So the influence of the water film thickness on the piston pair was analyzed in detail. An optimal model, with the minimum of the total power loss of the piston pair as optimization objective, was established, which refers to the hydrostatic bearing characteristics of piston pair. The parameters of piston pair were obtained by optimum design. When θ0 is 19°, the diameter of piston tail is 15 mm and the diameter of damper orifice is 0.18 mm, the optimum water film thickness of piston pair is 2.027 μm. The research shows that optimized piston pair has lower power loss, good lubricating performance, and higher static and dynamic performance.

关键词： Pistons

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Research on the Relationship between Classic Denavit-Hartenberg and Modified Denavit-Hartenberg

Research on the Relationship between Classic Denavit-Hartenb...

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International Symposium on Computational Intelligence and Design, ISCID

作者： Hang Wang Hanghang Qi Minghui Xu Yanhua Tang Jiantao Yao Xuedong Yan Ming Li Shanghai University Haitian Plastics Machinery Ltd. Ningbo HAITIAN Drive Systems Co. Ltd. Yanshan University Parallel Robot and Mechatronic System Laboratory of Hebei Province Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Department of Chemistry Northeast Normal University NINGBO VEKEN BATTERY CO. LTD

ISBN: (纸本)9781479970063

Currently, homogeneous transformation method has been widely used for its advantages in robot. Its more commonly used modeling methods are classic Denavit-Hartenberg method and modified Denavit-Hartenberg method, but the relationship between the two is very few devoted. Then, the use area is limited. Therefore, the relationship between classic Denavit-Hartenberg method and modified Denavit-Hartenberg method for robotics research has important practical significance. Based on this, the geometric representations of classic Denavit-Hartenberg method and modified Denavit-Hartenberg method are described respectively, the models of link parameters are built by the two, and the corresponding transformation matrix is deduced. The relationship between classic Denavit-Hartenberg method and modified Denavit-Hartenberg method is researched deeply, and the relational expression of classic Denavit-Hartenberg method and modified Denavit-Hartenberg method is obtained. The research results of this paper are useful for the robot kinematics, dynamics and control algorithms.

关键词： Joints Kinematics Heuristic algorithms Service robots Robot kinematics Mechatronics

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Microstructure, Tensile Properties and Heat-Resistant Properties of Selective Laser Melted Almgsczr Alloy Under Long-Term Aging Treatment

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SSRN 2022年

作者： Bi, Jiang Liu, Lei Chen, Guang Jia, Xiangdong Chen, Xi Xia, Hongbo Li, Xiaopeng Starostenkov, Mikhail Dmitrievich Han, Bing Dong, Guojiang Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China College of Mechanical and Electrical Engineering Nanjing Forestry University Nanjing210037 China State Key Laboratory of Advanced Welding and Joining Harbin Institute of Technology Harbin150001 China School of Mechanical Engineering Yangzhou University Yangzhou225127 China College of Material Science and Engineering Nanjing University of Science and Technology Nanjing210094 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia Institute of Intelligent Manufacturing Guangdong Academy of Sciences Guangdong Key Laboratory of Modern Control Technology Guangzhou510070 China

Selective laser melting (SLM)-processed AlMgScZr alloy has aroused widespread interest in the aerospace industry due to its outstanding comprehensive performance and excellent heat resistant properties. The fine grain morphology and diffusely distributed thermally stable precipitates of this alloy are believed to play a critical role in its high-temperature performance. By modifying the alloy with Sc and Zr, nano-sized Al3(Sc, Zr) phases can act as heterogeneous nucleating particles to effectively promote grain refining and precipitate strengthening. In this paper, a Sc and Zr-modified Al-Mg alloy was printed by SLM, and the long-term aging treatments in the temperature range of 275-350 ℃ with a constant holding time of 144 h were performed to investigate the heat-resistant properties of this alloy. Under as-fabricated condition, the AlMgScZr alloy exhibited high tensile strengths of 487.7 MPa and 393.9 MPa at temperatures of 25 ℃ and 200 ℃, respectively. When the alloy was aged at 300 ℃ for 144 h, its grain morphology was almost unchanged, but its tensile strength and elongation at room temperature reached 501.3 MPa and 31.3 %, respectively. This SLM-fabricated AlMgScZr alloy is expected to replace some titanium alloy components for medium-temperature applications. © 2022, The Authors. All rights reserved.

关键词： Aluminum alloys

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Deployable unit 3R-3URU and its application in deployable truss antenna

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Hangkong Xuebao/Acta Aeronautica et Astronautica Sinica 2017年第11期38卷 421285页

作者： Liu, Wenlan Xu, Yundou Yao, Jiantao Chen, Liangliang Wang, Hui Zhao, Yongsheng Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science of Ministry of Education Yanshan University Qinhuangdao066004 China Xi'an710100 China

A spatial deployable unit 3R-3URU with one Degree of Freedom (DoF) is proposed. The DoF of the single closed-loop mechanism RURUR is analyzed, based on the screw theory and the modified G-K formula. The analytical expression for the velocities of active joints and passive joints of the mechanism RURUR are then established. According to the velocity expression and the structural characteristic that three RURUR mechanisms share their first and last revolute joints, the DoF of the 3R-3URU mechanism is derived. The geometrical relationship among the positions and directions of all joints is also obtained when the 3R-3URU mechanism has one DoF. Novel deployable mechanisms are obtained by applying the 3R-3URU mechanism to the 3RR-3RRR tetrahedral unit and a deployable truss antenna composed of the tetrahedral units, and the novel mechanisms have two types of DoFs: movement and orientation adjustment. DoF analysis and application of the 3R-3URU deployable unit are verified by the Adams software. The proposed deployable unit 3R-3URU has the advantages of one DoF, simple structure, and single type of joints, and can be applied to the supporting mechanism of deployable truss antennas with a curved surface to achieve a large folding ratio. © 2017, Press of Chinese Journal of Aeronautics. All right reserved.

关键词： Degrees of freedom (mechanics)

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Functional microstructural surface manufacturing and assessment

Functional microstructural surface manufacturing and assessm...

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第五届国际仿生工程学术大会(ICBE2016)

作者： Xun Chen James Wharton Zhiqing Hu Chengchun Zhang Haolin Li Haoyang Cao Advanced Manufacturing Technology Research Laboratory General Engineering Research InstituteLiverpool John Moores Unisity Rolling Forging Research Institute Jilin University Key Laboratory of Engineering Bionics (Ministry of Education) Jilin University College of Mechanical Engineering University of Shanghai for Science and Technology

Reduction of energy consumption is one of key issues for the sustainable development. Recent technological development in manufacturing technology has enabled engineers to create surfaces with defined geometrical structures. This paper will presents a review of the currently available literature surrounding the research of functional structural surfaces in relation to the beneficial properties, such as frictional reduction and drag reduction. Various manufacturing methods for the creation of microstructural surface will be compared in terms of production efficiency and economic production scale. A particular focus will be put on grinding which provides a new way for structural functional surface creation. Many researchers have attempted to relate the measured parameters of micro-structured surfaces to different functions. The paper will present some research results on the metrological parameters, which are currently used in industry. The investigation results show that the commonly used surface roughness measure, for example, Ra, may not be the best parameter for the functional surface quality control in terms of tribological performance. With the investigation conducted, it would suggest that 3D measurement parameters could be better that those 2D parameters. It was found that some particular structures on functional surface possess beneficial functions that could reduce energy consumption. Some recent investigations in LJMU will also be introduced to demonstrate the benefits could be acquired from microstructural surfaces.

关键词： microstructural surface manufacture assessment

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Structure Parameters and Displacement Equations of Goldberg Mechanisms With the Rank More Than sixStructure Parameters and Displacement Equations of Goldberg Mechanisms With the Rank More Than Six

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Research Square 2020年

作者： Zhang, Yitong Lu, Ling Liu, Wenlan Li, Yanwen Hu, Bo Mu, Dejun Lu, Wenjuan Parallel Robot and Mechatronic System Laboratory of Hebei Province Yanshan University Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of National Education Yanshan University Qinhuangdao066004 China Heavy-duty Intelligent Manufacturing Equipment Innovation Center of Hebei Province Yanshan University Qinhuangdao066004 China College of Energy and Power Engineering Lanzhou University of Technology Lanzhou730050 China

An infinite number of N-bar Goldberg mechanisms with the rank more than six are proposed. A single closed-loop eight-bar mechanism is first developed by removing the common side links of adjacent loops from the five-loop Bennett mechanism in which all loop frames are collinear. An analysis of trajectory circles of the links shows that the mechanism developed maintains the original constraint conditions and kinematic characteristics, and that its degree of freedom (DOF) is also one. This novel single-loop mechanism is named the eight-bar Goldberg mechanism because of its similar constraint characteristics with the five-bar and six-bar Goldberg mechanisms. The eight displacement parameters of this mechanism are analyzed by using the interior angles of adjacent links, and the five cosine equations for the tangent product of the stagger angles between adjacent links are established in together with one angular displacement equation of odd links and one angular displacement equation of even links. This novel mechanism has one DOF, eight displacement parameters and seven independent displacement equations. The loop rank of the eight-bar Goldberg mechanism is seven, which revises the existing mechanism theory of single closed-loop mechanisms with the rank no more than six. Similarly, a nine-bar Goldberg mechanism is constructed, and its nine displacement parameters are analyzed. This mechanism has eight independent displacement equations and the loop rank is eight, proving that the mechanisms with the rank more than six are not rare. Then, according to the characteristics of the independent displacement equations of the eight-bar and nine-bar Goldberg mechanisms, the N (N>7) displacement parameters of N-bar Goldberg mechanisms are analyzed, and the (N–1) independent displacement equations are deduced with odd and even Ns. It is proved that the loop rank of N-bar Goldberg mechanisms is (N–1), so there exist an infinite number of mechanisms with the rank more than six. © 202

关键词： Degrees of freedom (mechanics)

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