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Powder technology 2025年 463卷

作者： Haiwei Shi Changcai Zhao Bing Du Guoyi Shen Hengkai Ren Key Laboratory of Advanced Forging & Stamping Technology and Science (YanShan University) Ministry of Education of China Qinhuangdao 066004 China

To analyze the internal interactions of solid granules medium (SGM) and their interactions with sheet metal during the SGM deep drawing forming process, the discrete element method (DEM) is used for the SGM, and the finite element method (FEM) is employed for the sheet metal. A new FEM-DEM coupling method is developed based on the force conservation principle. To address the issues of circularity and deformation under high pressure present in the SGM, the rolling resistance linear (RRL) model is applied. A high-precision inversion method utilizing the back propagation neural network-particle swarm optimization (BP-PSO) algorithm is proposed to enhance the efficiency of DEM parameter calibration. The SGM deep drawing forming process is conducted and compared with the simulation results of the FEM-DEM coupling model, which confirms the accuracy of the coupling model. This model analyzes force transmission and flow of the granules, efficiently visualizing interactions during the forming process.

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High-temperature fracture behavior of MnS inclusions based on GTN model

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Journal of Iron and Steel Research International 2019年第9期26卷 941-952页

作者： Xin-gang Liu Can Wang Qing-feng Deng Bao-feng Guo Key Laboratory of Advanced Forging and Stamping Technology and Science (Yanshan University) Ministry of Education of ChinaQinhuangdao 066004HebeiChina

The influence of the MnS plastic inclusion on the accumulation of internal damage was considered, and the Gurson– Tvergaard–Needleman (GTN) model was calibrated based on the finite element inverse method and image analysis method using ABAQUS and GTN models. The modified GTN damage model was used to simulate the initiation and propagation of cracks in an as-cast 304 stainless steel with MnS inclusions at 900 C. The simulation results agreed well with the experimental results, indicating that the model can be effectively applied to examine the high-temperature fracture behavior of MnS inclusions. The simulation and high-temperature tensile test results revealed that MnS inclusions increased the number of holes initiation and the probability of hole polymerization, reduced the crack propagation resistance, accelerated the occurrence of material fracture behavior, and were closely related to the stress state at high temperatures. When the stress triaxiality was low, the plastic strain in the metal matrix was high, and the MnS plastic inclusions accelerated the polymerization of the pores, making metal fracture failure more likely. On the other hand, when the stress triaxiality was high, the stress state in the metal matrix was biased to the tensile state, the plastic strain in the metal matrix was low, and the influence of MnS plastic inclusions on the fracture behavior was not evident.

关键词： MnS inclusion GTN model Tension High-temperature fracture behavior Crack initiation Crack propagation Stress

Analytical and Experimental Studies of the Improved Conductance-Stability and Stretchability of the Liquid Metal-Embedded Composites Based on a Novel Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Wang, Xi Guo, Shu Chen, Shuang Luo, Yiwen Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we combined analytical and numerical analyses with experimental studies to investigate effects of the innovatively designed continuous annular-shaped branch channels, inspired by the Tesla valve, on the performances of the LM-embedded conductive composite. Theoretically, in the process of mechanical deformations, the as-proposed continuous annular-shaped architecture can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. Experimentally, the as-fabricated composite conductor with continuous annular-shaped branch channels can be stretched up to ~80% (more than two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the understanding and application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

A Stretchable and Conductance-Stable Composite Based on a Liquid Metal-Embedded Elastomer with Continuous Annular-Shaped Branch Channels

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SSRN 2023年

作者： Li, Jing Chen, Shuang Guo, Shu Luo, Yiwen Zheng, Zhong Li, Xiuhong Zhao, Shiyan School of Mechanical Engineering Hubei Modern Manufacturing Quality Engineering Key Laboratory Hubei University of Technology Hubei Wuhan430068 China School of Mechanical and Electrical Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China School of Vehicle and Energy Yanshan University Hebei Qinhuangdao066004 China Key Laboratory of Advanced Forging and Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Stretchable and conductance-stable composites are critical for progress in flexible electronics. Tremendous efforts have focused on engineering electrical conductors from liquid metal-embedded elastomers. While these elastomers enable elastic compliance and deformability, the embedded liquid metal is vulnerable to puncture that cause undesired electrical failure, and most of the conductive elastomers are strain sensitive with degenerative conductance upon deformations. Here, we report a versatile and practical approach to prepare stretchable LM-embedded elastomeric conductors with continuous annular-shaped branch channels. In the process of mechanical deformations, the annular-shaped branch channels can dissipate the pressure energy of the fluidic LM to enhance the fracture toughness of the composite, while the LM flow could be accelerated as the deformation was removed to maintain the percolated conductive path, leading to excellent conductive stability. The as-proposed composite conductor can be stretched up to ~80% (two times higher than conventional LM-embedded composite), and upon fully activating the conductive pathway, a very high conductivity of ~4×104 S·m-1 and conductance change of less than 2% under varied deformations, including stretching, flexing, twisting and compressing, are realized. It is believed that this novel design strategy will extend the application opportunities of LM as functional materials in the development of flexible electronics. © 2023, The Authors. All rights reserved.

关键词： Liquid metals

Process Optimization of A356 Aluminum Alloy Wheel Hub Fabricated by Low-Pressure Die Casting with Simulation and Experimental Coupling Methods

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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

Molecular Dynamics Simulation Analysis of the Indentation Hardness of Nano-Twinned Ni

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SSRN 2022年

作者： Zhang, Qin Zhou, Bingrao Wang, Wei Li, Rongbin Lv, Zhiqing Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Ministry of Education of China Qinhuangdao066004 China State Key Laboratory of Metastable Material Science and Technology Yanshan University Qinhuangdao066004 China Shanghai Engineering Research Center of Hot Manufacturing Shanghai Dianji University Shanghai200245 China

Molecular dynamics simulations were employed to perform the nanoindentation analysis of nanocrystalline nickel with different crystal structures (single-crystal, polycrystalline, and nano-twinned) and twin layer thicknesses under a spherical indenter. To understand the effects of crystal structure and twin spacing on nanoindentation responses, the crystal structure, dislocation, strain, indentation force, temperature, hardness, Young's modulus, and elastic recovery rate of the indentation region were analyzed. It was noticed that crystal structure and twin spacing had great influences on the mechanical properties and elastic recovery rate of the three types of nanocrystalline nickel. In the single-crystal structure, plastic deformation occurred mainly due to dislocations and slips. In the polycrystalline structure, plastic deformation occurred due to dislocation–grain boundary interactions, whereas in the nano-twinned structure, dislocation–grain boundary and dislocation–twin boundary interactions were the main reasons for plastic deformation. In the single-crystal structure, the hydrostatic pressure was distributed in a "V"-shape below the indenter. In the polycrystalline structure, atoms under the compressive stress were distributed below the indenter and at crystal boundaries. In the nano-twinned structure, atoms under the compressive stress were mainly distributed below the indenter. © 2022, The Authors. All rights reserved.

关键词： Nanoindentation

A New Method for Type Synthesis of 2R1T and 2T1R 3-DOF Redundant Actuated Parallel Mechanisms with Closed Loop Units

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Chinese Journal of Mechanical Engineering 2020年第6期33卷 134-157页

作者： Yongquan Li Yang Zhang Lijie Zhang 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 School of Mechanical Engineering and Automation Harbin Institute of TechnologyShenzhen518052China Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan UniversityQinhuangdao066004China

The current type synthesis of the redundant actuated parallel mechanisms is adding active-actuated kinematic branches on the basis of the traditional parallel mechanisms,or using screw theory to perform multiple getting intersection and union to complete type *** number of redundant parallel mechanisms obtained by these two methods is *** this paper,based on Grassmann line geometry and Atlas method,a novel and effective method for type synthesis of redundant actuated parallel mechanisms(PMs)with closed-loop units is ***,the degree of freedom(DOF)and constraint line graph of the moving platform are determined successively,and redundant lines are added in constraint line graph to obtain the redundant constraint line graph and their equivalent line graph,and a branch constraint allocation scheme is formulated based on the allocation ***,a scheme is selected and redundant lines are added in the branch chains DOF graph to construct the redundant actuated branch chains with closed-loop ***,the branch chains that meet the requirements of branch chains configuration criteria and F&C(degree of freedom&constraint)line graph are *** this paper,two types of 2 rotational and 1 translational(2R1T)redundant actuated parallel mechanisms and one type of 2 translational and 1 rotational(2T1R)redundant actuated parallel mechanisms with few branches and closed-loop units were taken as examples,and 238,92 and 15 new configurations were *** the mechanisms contain closed-loop units,and the mechanisms and the actuators both have good ***,all the mechanisms have excellent comprehensive performance,in which the two rotational DOFs of the moving platform of 2R1T redundant actuated parallel mechanism can be independently *** instantaneous analysis shows that all mechanisms are not instantaneous,which proves the feasibility and practicability of the method.

关键词： Redundant actuated Parallel mechanisms Type synthesis Atlas method Instantaneous analysis

δ-phase precipitation regularity of cold-rolled fine-grained GH4169 alloy plate and its effect on mechanical properties

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Transactions of Nonferrous Metals Society of China 2020年第12期30卷 3287-3295页

作者： Hao XUE Jing-qi ZHAO Yong-kang LIU Chun-xiang ZHANG Jun-ting LUO Key Laboratory of Advanced Forging&Stamping Technology and Science of Ministry of Education Yanshan UniversityQinhuangdao 066004China State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004China

Cold rolling and heat-treatment were used for the grain refinement of GH4169 superalloy *** effects of cold rolling reduction ratio and heat-treatment time on the precipitatedδphase,and the effects ofδ-phase content and morphology on the mechanical properties of the GH4169 alloy plates,are *** results demonstrate that coldrolling can promote the precipitation of theδphase and its transformation from theδ-Ni3Nb phase to theδ-NbNi4 *** comprehensive properties of the alloy are better when the heat treatment time is 1 h,with 132 MPa increase in the tensile strength and only 2.9%decrease in the elongation relative to those of the original *** mechanical properties of the alloy are shown to change greatly with the change in theδ-phase morphology.

关键词： fine-grained GH4169 alloy cold rolling δphase mechanical properties

A Mechanical Model of Internal Expansion Over Bending and Calibration (Ieobc) Process For Large-Diameter Pipe End

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SSRN 2024年

作者： Qi, Shaocong Yu, Gaochao Shi, Zhaocheng Zhang, Zifeng Han, Yashuai Zhao, Feiping Li, Senlin Zhao, Jun Key Laboratory of Advanced Forging & Stamping Technology and Science Yanshan University Ministry of Education of China China Department of Mechanical Engineering Imperial College London LondonSW7 2AZ United Kingdom National-Local Joint Engineering Research Center for Advanced Manufacturing Forming Technology and Equipment Yanshan University China Hebei Engineering Technology Research Center of Metal Precision Plastic Processing Yanshan University China Nantong Chaoli Rolling Machine Producing Co. Ltd Nantong China

In the process of laying urban pipeline networks, it is necessary to cut the pipes, and the residual stress of the cut pipes is released, resulting in an increase in the ovality of the cut section. Therefore, roundness calibration of the pipe ends is required. The internal expansion over bend and calibration (IEOBC) process is an efficient technique used for on-site calibration of the ovality of pipe ends. To accurately analyze the deformation behavior of pipe ends and improve its ovality, the mechanical model of the IEOBC process is established based on the static equilibrium equation, elastic-plastic deformation physical equation, deformation coordination equation, and constraint equation, which can be regarded as a statically indeterminate problem. The variation law of the ovality in the pipe end cross-section during the calibration process is analyzed. A control strategy for pipe end IEOBC process was proposed based on the functional relationship between the ovality and relative displacement. Calibration experiments are conducted on a mobile intelligent calibration machine. After the IEOBC process, the pipe end cross-section with initial ovality of 2.31% and 2.69% was reduced to 0.18% and -0.31%, respectively, meeting the pipe specification of API SPEC 5L. The IEOBC process and the control strategy proposed in this study can be applied to the roundness calibration of pipe end cross-section during pipe installation. © 2024, The Authors. All rights reserved.

关键词： Expansion

Effect of Process Parameters on the Formability, Microstructure and Mechanical Properties of Laser-Arc Hybrid Welding of Q355b Steel

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SSRN 2022年

作者： Bi, Jiang Zhang, Liping Peng, Genchen Yuan, Xiaoming Li, Wen Zhang, Lijie Hebei Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Qinhuangdao066004 China Jiangsu XCMG Construction Machinery Research Institution Ltd. Xuzhou221000 China Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education of China Yanshan University Qinhuangdao066004 China

Thick plate steel structure is widely used in construction machinery, pressure vessels, ships and other manufacturing fields. To obtain an acceptable welding quality and efficiency, the thick plate steel is always joined by laser-arc hybrid welding technology. In this paper, the Q355B steel with the thickness of 20 mm was taken as the research object, and the process of narrow groove laser-arc hybrid welding was studied. The results showed that the laser-arc hybrid welding method could realize one backing and two filling welding with the single groove angles of 8-12°. At different plate gaps of 0.5 mm, 1.0 mm and 1.5 mm, and the shape of weld seams were satisfied with no undercut, blowhole or other defects. The average tensile strength of welded joints was 486~493 MPa, and the fracture position was in the base metal area. Due to the high cooling rate, a large amount of lath martensite formed in heat affected zone (HAZ) and this zone exhibited higher hardness values. The impact roughness of the welded joint was almost 66-74 J with different groove angles. © 2022, The Authors. All rights reserved.

关键词： Microstructure