检索结果-内蒙古大学图书馆

SSRN 2024年

作者： Bi, Jiang Wang, Keqi Wu, Chen Chi, Jinze Liu, Bokun Zhang, Liping Chen, Xi Lu, Nannan Starostenkov, Mikhail Dmitrievich Dong, Guojiang Qin, Xikun Key Laboratory of Advanced Forging & Stamping Technology and Science Ministry of Education Yanshan University Qinhuangdao066004 China National Key Laboratory for Precision Hot Processing of Metals Harbin Institute of Technology Harbin150001 China Institute of Metal Research Chinese Academy of Sciences Shenyang110016 China General Physics Department Altai State Technical University Leninst. 46 Barnaul656099 Russia

In this work, a novel aluminum alloy with high Zn content was designed for laser powder bed fusion (LPBF) forming process. Aluminum alloy powder containing 14 wt.% Zn and 2 wt.% Zr was produced to conduct LPBF experiments with different process parameters. The analysis of the specimens revealed that the up facing surface exhibited an average microhardness peak value of 170.6 HV, achieving the ultimate tensile strength (UTS) of 573 MPa and the elongation of 11.6%. There was no significant change in grain size and a large amount of plate-like η' phase precipitated within the grains after aging treatment (120°C, 21h). The specimen reached the average microhardness peak of 181.7 HV and the UTS of 605 MPa. The principal strengthening mechanisms in the LPBF-formed samples were solid solution strengthening and grain refinement strengthening. After aging treatment, the precipitation of the second phase from solute atoms led to grain refinement strengthening and second-phase strengthening becoming the predominant factors to enhance the sample's strength. Al14ZnMgZr alloy have great application prospect in high strength and tough service environment. © 2024, The Authors. All rights reserved.

关键词： Aluminum alloys

Calibration of discrete element parameters and FEM-DEM coupling analysis for solid granules medium deep drawing forming

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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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Multi-Scale GHG Emission Relations in Resource-Based Heavy Industrial Cities: A Case Study of Tangshan City, Hebei Province

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Chinese Journal of Urban and Environmental Studies 2021年第4期9卷 74-98页

作者： HAN Mengyao JIANG Chuan LIU Siyuan Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key Laboratory of Regional Sustainable Development Modeling Chinese Academy of Sciences School of Mechanical Engineering Yanshan University Hebei Provincial Key Laboratory of Heavy Machinery Fluid Power Transmission and Control Yanshan University Key Laboratory of Advanced Forging & Stamping Technology and Science (Ministry of Education of China)Yanshan University

The greenhouse gas(GHG) emission pressure faced by resource-based heavy industrial cities was mainly induced by multi-scale interactions, which require systematical assessments from local,regional, national and global scales. Taking Tangshan city, a heavy industry base in Hebei Province of China, as the research area, this study carried out a multi-scale analysis on the GHG emissions in terms of final demand, final consumption and trade balance. The main results are as follows:(1) The average embodied intensity of GHG emissions in Tangshan was 27.6 tons/10,000 CNY, of which 66.2% was caused by local inputs;(2) The secondary industry was the main source for the relatively high GHG emissions in Tangshan;(3) The GHG emissions embodied in final demand were 201.6 million tons, within which the proportion of fixed capital formation reached 59.4%;(4) As for the trade balance, Tangshan was a net exporter of embodied GHG emissions, with the total net outflows of 411.6 million tons. Depicting the GHG emission flows and sorting out the multiple GHG emission inventory would be helpful to identify the transformation pressure of resource-based heavy industry cities, which would be significant for the adjustments in industrial structures and policy optimization of energy saving and emissions reduction.

关键词： Resource-based heavy industry city embodied greenhouse gas emissions multi-scale input–output analysis

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

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

Effect of Heterogeneous Deformation on Microstructure and Microtexture Evolution of Ti-6al-4v Alloy During Multi-Directional Isothermal forging

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SSRN 2023年

作者： Zhang, Zhixiong Zhang, Simo Huang, Wenhao Zhang, Juntao Yuan, Ruilin Jia, Yi Zhang, Changjiang Han, Jianchao Wang, Tao College of Mechanical and Vehicle Engineering Taiyuan University of Technology Shanxi Taiyuan030024 China National Key Laboratory of Metal Forming Technology and Heavy Equipment Shanxi Taiyuan030024 China Engineering Research Center of Advanced Metal Composites Forming Technology and Equipment Ministry of Education Shanxi Taiyuan030024 China College of Materials Science and Engineering Taiyuan University of Technology Shanxi Taiyuan030024 China

The heterogeneous deformation of Ti-6Al-4V alloy during multi-directional isothermal forging and its effect on microstructure and microtexture evolution were investigated by EBSD analysis. It was found that due to the change of forging times and forging directions, the titanium alloy billets underwent non-uniform deformation, and three kinds of microstructure of lamellar structure, heterogeneous lamellar structure and ultrafine equiaxed structure were formed respectively along the forging direction. The heterogeneous lamella structure had better synergy of strength and ductility, while the ultrafine equiaxed structure exhibited higher strength (1195 MPa) and lower strain hardening rate and ductility. The excellent comprehensive mechanical properties of heterogeneous lamella were attributed to back stress hardening and dislocation hardening. This study has guiding significance for the regulation of microstructure and the acquisition of titanium alloy with good performance. © 2023, The Authors. All rights reserved.

关键词： Aluminum alloys

An Iterative Compensation Algorithm for Springback Control in Plane Deformation and Its Application

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 212-223页

作者： Rui Ma Chunge Wang Ruixue Zhai Jun Zhao Key Laboratory of Advanced Forging & Stamping Technology and ScienceMinistry of Education of China Yanshan University College of Mechanical Engineering Yanshan University College of Mechanical and Energy Engineering Ningbo Institute of Technology Zhejiang University Key Laboratory of Roll Forming Technology Research

In order to solve the springback problem in sheet metal forming, the trial and error method is a widely used method in the factory, which is time-consuming and costly for its non-direction and non-quantitative. Finite element simulation is an e ective method to predict the springback of complex shape parts, but its precision is sensitive to the simulation model, particularly material model and boundary conditions. In this paper, the simple iterative method is introduced to establish the iterative compensation algorithm, and the convergence criterion of iterative parameters is put forward. In addition, the new algorithm is applied to the V-free bending and stretch-bending processes, and the convergence of curvature and bending angle is proved theoretically and verified experimentally. At the same time,the iterative compensation experiments for plane bending show that, the new method can predict the next compensaantido tnh ev atlaureg ebta cseurdv oatnu trhe ew sitphri tnhgeb earcrko ro fo fe laecshs ttehsat,n s0 o. 5 th%a ta rteh eo btatraigneet db aefntedri n2 g-3 a nitgelrea tiwoitnhs.t Thhei se rrreosre aorf clhe sps rtohpaons e±s 0 a.1%new iterative compensation algorithm to predict springback in sheet metal forming process, where each compensation value depends only on the iteration parameter di erence before and after springback for the same forming process of same material.

关键词： Springback control Iterative compensation algorithm Convergence criterion V-free bending Stretchbending

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

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