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Finite Element Simulation of Flexible Roll Forming with Supplemented Material Data and the Experimental Verification

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Chinese Journal of Mechanical Engineering 2016年第2期29卷 342-350页

作者： YAN yu WANG Haibo LI Qiang guan Yanzhi School of Mechanical and Material Engineerin North China University of Technology

Flexible roll forming is a promising manufacturing method for the production of variable cross section products. Considering the large plastic strain in this forming process which is much larger than that of uniform deformation phase of uniaxial tensile test, the widely adopted method of simulating the forming processes with non-supplemented material data from uniaxial tensile test will certainly lead to large error. To reduce this error, the material data is supplemented based on three constitutive models. Then a finite element model of a six passes flexible roll forming process is established based on the supplemented material data and the original material data from the uniaxial tensile test. The flexible roll forming experiment of a B pillar reinforcing plate is carried out to verify the proposed method. Final cross section shapes of the experimental and the simulated results are compared. It is shown that the simulation calculated with supplemented material data based on Swift model agrees well with the experimental results, while the simulation based on original material data could not predict the actual deformation accurately. The results indicate that this material supplement method is reliable and indispensible, and the simulation model can well reflect the real metal forming process. Detailed analysis of the distribution and history of plastic strain at different positions are performed. A new material data supplement method is proposed to tackle the problem which is ignored in other roll forming simulations, and thus the forming process simulation accuracy can be greatly improved.

关键词： 3D Flexible roll forming constitutive model material data supplementation finite element method experiment verification

Boosting electromagnetic wave absorption of Ti_(3)AlC_(2) by improving effective electrical conductivity

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Journal of Advanced Ceramics 2023年第8期12卷 1533-1546页

作者： Kai-yu Guo Lin Chen guan-Jun Yang State Key Laboratory for Mechanical Behavior of Materials School of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China

Electromagnetic wave-absorbing(EMA)materials at high temperatures are limited by poor conduction loss(L_(c)).However,adding conductors simultaneously increases the conduction loss and interfacial polarization loss,leading to a conflict between impedance matching(Z_(in)/Z_(0))and electromagnetic wave *** will prevent electromagnetic waves from entering the EMA materials,finally reducing overall absorbing ***,the effective electrical conductivity(σ)is enhanced by synchronizing particle size and grain number of Ti_(3)AlC_(2) to increase the conduction loss and avoid the conflict between the impedance matching and the electromagnetic wave *** a result,the best-absorbing performance with an effective absorption bandwidth(EAB)of 4.8 GHz(10.6–15.4 GHz)at a thickness of only 1.5 mm is realized,which is the best combination of wide absorption bandwidth and small thickness,and the minimum reflection loss(RL_(min))reaches−45.6 dB at 4.1 *** short,this work explores the regulating mechanism of the EMA materials of effective electrical conductivity by simulated calculations using the Vienna ab-initio Simulation Package(VASP)and COMSOL as well as a series of experiments,which provide new insight into a rational design of materials with anisotropic electrical conductivity.

关键词： anisotropic electrical conductivity conduction loss(Lc) interfacial polarization loss(LIP) effective electrical conductivity co-optimize impedance matching(zin/Z0) electromagnetic wave loss

Temperature-dependent tensile properties of ultrafine-grained C-doped CoCrFeMnNi high-entropy alloy

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Rare Metals 2022年第8期41卷 2877-2885页

作者： Yan-Zhong Tian Si-yuan Peng Shang-Feng Chen zi-Jian Gu Yang Yang Xiu-Ling Shang guan-yu Deng Li-Hong Su Shi-Jie Sun Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang110819China Innovation Center of GD Midea Air-Conditioning Equipment Co. LtdFoshan528311China School of Mechanical MaterialsMechatronic and Biomedical EngineeringUniversity of WollongongWollongongNSW2500Australia Institute of Metal Research Chinese Academy of SciencesShenyang110016China

Metallic materials can be strengthened by various kinds of plastic deformation ***,the deformed materials suffer poor ductility and thermal stability due to the high-density *** this work,we prepared fully recrystallized ultrafine-grained(UFG)1%CCoCrFeMnNi high-entropy alloy(C-HEA)through cold rolling and annealing ***-static tensile tests were performed at temperatures between 77 and 823 *** micros true tures of the samples after tensile tests were characterized,and deformation mechanisms were *** is a transition of deformation mechanisms from twinning and dislocation slip to dislocation slip and grain boundary sliding with temperature *** UFG C-HEA exhibits balanced strength and ductility from the cryogenic temperature to high temperatures,indicating highly adaptive microstructure and mechanical *** strength and uniform elongation of the UFG C-HEA decrease monotonously with temperature increasing,but the elongation to failure exhibits the lowest value at the medium *** grain boundary sliding is supposed to assist the unconventionally high elongation at 823 K.

关键词： High-entropy alloy Temperature Ductility Strength Ultrafine grain

Numerical simulations of sloshing waves in vertically excited square tank by improved MPS method

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Journal of Hydrodynamics 2022年第1期34卷 76-84页

作者： guan-yu Zhang Wei-wen Zhao De-cheng Wan Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

Faraday wave is a phenomenon of sloshing due to a heave motion of a partially filled tank,which is also called parametric instability or parametric *** the present paper,the phenomenon of faraday wave in a pure heave excited square tank is numerically simulated through the moving particle semi-implicit(MPS)*** surface tension effect and a new Dirichlet boundary condition for the pressure Poisson equation are considered to avert unphysical fragmentation and clustering of particles in splash *** the numerical simulation,the evolution of wave motion,and the non-linearity together with breaking phenomenon of faraday wave can be *** agreement is good in general,both amplitude and ***,the parameter studies including the excitation frequency and the forcing amplitude are carried out to analyses the mechanism of resonances response.

关键词： Liquid sloshing faraday wave moving particle semi-implicit(MPS)method surface tension MLParticle-SJTU solver

A Generalized Numerical Approach for Modeling Multiphase Flow and Transport in Fractured Porous Media

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Communications in Computational Physics 2009年第6期6卷 85-108页

作者： yu-Shu Wu guan Qin Department of Petroleum Engineering Colorado School of MinesGoldenCO 80401USA Institute for Scientific Computation Texas A&M UniversityCollege StationTX 77843USA

A physically based numerical approach is presented for modeling multiphase flow and transport processes in fractured *** particular,a general framework model is discussed for dealing with fracture-matrix interactions,which is applicable to both continuum and discrete fracture *** numerical modeling approach is based on a general multiple-continuum concept,suitable for modeling any types of fractured reservoirs,including double-,triple-,and other multiplecontinuum conceptual *** addition,a new,physically correct numerical scheme is discussed to calculate multiphase flow between fractures and the matrix,using continuity of capillary pressure at the fracture-matrix *** proposed general modeling methodology is verified in special cases using analytical solutions and laboratory experimental data,and demonstrated for its application in modeling flow through fractured vuggy reservoirs.

关键词： Integrated finite difference conservation of mass and energy Newton iteration fully implicit reservoir simulation fractured rock

Minimizing Age of Information in the Uplink Multi-User Networks via Dynamic Bandwidth Allocation

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China Communications 2023年第4期20卷 287-301页

作者： Zeyuan Zhu Xinrong guan Baoquan yu Tian yu yueming Cai College of Communication Engineering Army Engineering University of PLANanjing 210007China Unit 31401 of PLA Jinan 250002China

Improving the information freshness is critical for the monitoring and controlling applications in the cellular Internet of Things(IoT).In this paper,we are interested in optimizing the bandwidth allocation dynamically to improve the information freshness of the short packet based uplink status updates,which is characterized by a recently proposed metric,age of information(Ao I).We first design a status update scheme with channel distribution information(CDI).By relaxing the hard bandwidth constraint and introducing a Lagrangian multiplier,we first decouple the multi-MTCD bandwidth allocation problem into a single MTCD Markov decision process(MDP).Under the MDP framework,after variable substitution,we obtain the single-MTCD status update scheme by solving a linear programming ***,we adjust the Lagrangian multiplier to make the obtained scheme satisfy the relaxed bandwidth ***,a greedy policy is built on the proposed scheme to adjust the bandwidth allocation in each slot to satisfy the hard bandwidth *** the unknown environment without CDI,we further design a bandwidth allocation scheme which only maximizes the expected sum Ao I drop within each time *** results show that in terms of AoI,the proposed schemes outperform the benchmark schemes.

关键词： Internet of Things age of information short packet communications bandwidth allocation

Enhancing insights into Global Cancer Statistics 2022: implications for cancer control

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Science China Life Sciences 2025年第1期 294-296页

作者： Jingtong Xu Runtian Wang Xiaoxiang guan Department of Oncology the First Affiliated Hospital of Nanjing Medical University Jiangsu Key Lab of Cancer Biomarkers Prevention and TreatmentCollaborative Innovation Center for Personalized Cancer MedicineNanjing Medical University

Globally, there has been a marked escalation in tumor morbidity and mortality,cementing tumors as the predominant cause of death in numerous *** the current tumor burden across various regions is imperative to discern potential risk factors and formulate efficacious strategies for tumor ***, the International Agency for Research on Cancer(IARC) provided a status report on the global tumor burden,estimating the incidence and mortality of 36 cancers in 185 countries(Bray et al.,2024).

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Gastroesophageal reflux disease at the turn of millennium

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World Journal of Gastroenterology 2003年第10期9卷 2135-2136页

作者： Lee-guan Lim Khek-yu Ho Department of Medicine National University HospitalSingapore

Gastroesophageal reflux disease (GERD) has been an area of active research in the Asia-Pacific region in the recent years. This article outlines some of the interesting research findings. It comprises three parts. The first part dealt with recent data on the changing epidemiology of GERD in *** second part summarized published studies on the relationship between GERD and Helicobacter pylori, relevant to the Asia-Pacific region. The last part discussed some of the recent advances in the treatment of GERD.

关键词： Gastroesophageal Reflux Helicobacter Infections Humans

Mesoscale simulation of discontinuous dynamic recrystallization using the cellular automaton method

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Acta Metallurgica Sinica(English Letters) 2011年第4期24卷 287-294页

作者： Baojun yu Xiaojun guan Lijun WANG Qingkai ZENG Qianqian LIU yu CAO Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials (Ministry of Education) School of Materials Science and Engineering Shandong University Jinan 250061 China

A dynamic recrystallization （DRX） cellular automaton （CA） model that can mark the microstructure with DRX circle was developed. The effects of initial grain size on the stress-strain curve, mean grain size and DRX fraction were mainly investigated, and the simulated results were compared with those obtained from previous researches. The results show that the shape of the stress-strain curve is sensitive, while the stress and mean grain size at the steady state are insensitive to the initial grain size. The transition from a multiple-peak stress-strain curve to a single-peak one can be explained by variations in DRX circle fraction, and the initial grain size to make this transition is between 70 and 80 tim.

关键词： Dynamic recrystallization Cellular automaton DRX circle Copper