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Number of results: 8
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Abstract

By simulating the actual working conditions of a cable, the temperature variation rule of different measuring points under different load currents was analyzed. On this basis, a three-dimensional finite element model (FEM) was established, and the difference and influence factors between the simulation temperature and the experimental measured value were discussed, then the influence of thermal conductivity on the operating temperature of the conductor layer was studied. Finally, combined with the steady-state thermal conductivity model and the experimental measured data, the relation between thermal conductivity and load current was obtained.

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Authors and Affiliations

Xiaokai Meng
Peijie Han
Yongxin Liu
Zhumao Lu
Tao Jin
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Abstract

In this contribution, an overview over a numerical scheme for the crack modelling of spruce wood under tensile loading is given. A material model for biaxially stressed spruce wood with consideration of the effect of knots on the strength properties has been developed. A necessary feature of this material model is its ability to treat cracks by means of the so-called smeared crack concept. For this reason the consideration of a so-called characteristic length in the corresponding evolution laws of the strength values is required. The successful implementation in the material model is shown by means of various numerical examples.
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Authors and Affiliations

Herbert W. Mulllner
Christoph Kohlhauser
Martin Fleischmann
Josef Eberhardsteiner
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Abstract

This research work is devoted to the theoretical study of the pipe calibration on a mandrel. The aim of the study is to improve the precision of the calibrated pipes. As the paper shows, it is advisable to apply different methods of research depending on the purpose of the study of metal forming processes: mathematical, computer or physical simulation. Analytical review of existing mathematical models of the pipes calibration on a mandrel showed that the set of assumptions adopted in the mathematical modeling does not allow assessing the precision of the pipes during calibration. Therefore, finite-element method simulation package was used for this research. Research method and pipes precision index were developed on the basis of the computer simulation using Deform-3D package. The investigations have allowed us to get the dependence of the pipe precision on technological factors and to identify the root cause of reduced efficiency calibration – extrafocal deformation.
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Authors and Affiliations

D. Salikhyanov
A. Bogatov
H. Dyja
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Abstract

The study proposed the model of “guide mark” defects formation on the internal surface of pipes, produced on PRM mills of PRP – 140. The research of pipe forming at plug rolling mill with stub mandrel has been carried out; regularities of the dimensionless parameters characterizing the deformation of the gap release, depending on the reduction ratio, were determined. The model of “guide mark” defect formation on the internal surface of the pipe has been proposed. This allows for lesser wall thickness variation of rough tubes. It has been shown that, when using dioctahedral pass designs in comparison with hexagonal pass designs the proportion of displaced volume along the pipe axis is greater but the value is lower; thereby, the risk of “guide mark” defect forming is reduced.

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Authors and Affiliations

D. Pavlov
A. Bogatov
E. Pavlova
H. Dyja
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Abstract

It is not easy to make the insulators of the railway catenary for the dry and cold environment of the icy Qinghai-Tibet plateau, without causing serious ice-related flashover accidents. To study the operating status of catenary icing insulators, a two-dimensional icing model of catenary cantilever insulators was established based on the winter environmental characteristics of the Golmud station on the Qinghai-Tibet Railway. Compared different directions of ice growth, the spatial electric field distribution, and surface temperature distribution characteristics of icing insulatorswere analyzed by multi-physical field coupling simulation. The results show that as the thickness of the ice layer increases and the length of the icicle increases, the field intensity of the insulator gradually increases, and the surface temperature continues to rise. When the ice edge grows vertically downward, the electric field intensity of the insulator is the smallest, and the electric field intensity is the largest when the ice edge grows horizontally. Although the surface temperature of the insulator will rise with the increase of icing degree, it is lower than the freezing point and will not have a great impact on insulation performance. Secondly, when the cantilever insulator is arranged obliquely, the increase in the inclination angle will cause the electric field to increase and the temperature to rise slightly, so the inclination angle of the oblique cantilever should be reduced as much as possible during installation. Finally, the insulator with better insulation performance is obtained by optimizing the structure of the flat cantilever insulator.
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Bibliography

[1] Meng Hong, Qinghai-Tibet Railway: The Magical "Sky Road" on the Roof of theWorld, Party Member’s Digest, no. 11, pp. 38–40 (2019).
[2] Fofana I., Farzaneh M. et al., Dynamic Modeling of Flashover Process on Insulator under Atmospheric Icing Conditions, 2001 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, Toronto, Canada, pp. 605–608 (2001).
[3] Tavakoli C., Farzaneh M., Fofana I. et al., Dynamics and Modeling of AC Arc on Surface of Ice, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 13, no. 06, pp. 1278–1283 (2006).
[4] Zhao Jiayao, Study on AC Flashover Characteristics of Nature Icing Suspension Insulator (Short) Strings, PhD Thesis, Chongqing University, Chongqing (2019).
[5] Zhang Zhijin, Cheng Yang, Zhao Jiayao et al., AC Flashover Performances of Artificial Icing and Nature Icing for XP-160 Insulator String, High Voltage Engineering, vol. 44, no. 09, pp. 2777–2784 (2018).
[6] Ciesielka W., Gołas A. et al., Reliability improvement of power distribution line exposed to extreme icing in Poland, Archives of Electrical Engineering, vol. 68, no. 05, pp. 1113–1125 (2020).
[7] Mhaguen N., Development of Dynamic Models for Predicting the Critical Flashover Voltage of Insulators Covered with Ice Based on Finite Element Method, Thesis of Master’s Degree, University of Québec, Canada (2011).
[8] Volat C., Farzaneh M. et al., Improved FEM models of one- and two-arcs to predict AC critical flashover voltage of ice-covered insulators, IEEE Transactions on Dielectrics and Electrical Insulation, vol. 18, no. 02, pp. 393–400 (2011).
[9] Lu Jiazheng, Xie Pengkang et al., Electric field simulation and sheds optimization of anti- icing and anti- lightning insulator under heavy icing condition, Electric Power Automation Equipment, vol. 38, no. 03, pp. 199–204 (2018).
[10] Tu Yewei, Xia Qiangfeng, Simulation of Space Electric Field Distribution Around 220 kV Porcelain Insulator String (XP-160) and the Influencing Factors, High Voltage Apparatus, vol. 48, no. 03, pp. 67–74 (2012).
[11] Qi Guiming, Wang fake, He Haicheng et al., Surface and low altitude wind field characteristics in Golmud city, Journal of Arid Land Resources and Environment, vol. 24, no. 06, pp. 118–120 (2010).
[12] Hu Yuyao, Study on Dynamic Model for Icing with Wet Growth Process and Ice Flashover Voltage Prediction of Suspension Insulators, Master Thesis, Chongqing University, Chongqing (2017).
[13] Luo Jian, The Optimization of the System Parameters and Cantilever and Positioning Device of Overhead Contact System of High-speed Railway, PhD Thesis, Southwest JiaotongUniversity, Chengdu (2017).
[14] Zhang Yuexin, Study on Catenary’s Construction Techniques in High-speed Electric Railway, PhD Thesis, Southwest Jiaotong University, Chengdu (2006).
[15] Sharma R.P., Seema Tinker et al. Effect of Convective Heat and Mass Conditions in Magnetohydrodynamic Boundary Layer Flow with Joule Heating and Thermal Radiation, International Journal of Applied Mechanics and Engineering, vol. 25, no. 03 (2020).
[16] Liao Jiajun, Yang Lin, Hao Yanpeng, Simulation of Electric Field for 110 kV Iced Composite Insulator in Melting Period, High Voltage Apparatus, vol. 51, no. 03, pp. 47–54 (2015), DOI: 10.13296/ j.l001-1609.hva.2015.03.008.
[17] Ravisha M., Raghunatha K.R., Mamatha A.L., B oundary effects on electrothermal convection in a dielectric fluid layer, Archives of Electrical Engineering, vol. 40, no. 1, pp. 3–19 (2019).
[18] Van Brunt R.J., Stochastic properties of partial-discharge phenomena, Electrical Insulation, IEEE Transactions, vol. 26, iss. 5 (1991), DOI: 10.1109/14.99099.
[19] An Dawei, Study on Needle-plate corona Discharge and Migration Characteristics of Ion Space Charge, PhD Thesis, Chongqing University, Chongqing (2017).

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Authors and Affiliations

Sihua Wang
1
ORCID: ORCID
Junjun Wang
1
Lijun Zhou
1
Long Chen
1
ORCID: ORCID
Lei Zhao
1

  1. Lanzhou Jiaotong University, China
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Abstract

With the development of wireless power transfer technology, more and more attention has been paid to its electromagnetic safety. In this paper, a novel hybrid shielding structure composed of the innermost fan-shaped ferrite, the interlayer nanocrystalline strip and the outermost aluminum foil is proposed to shield the electromagnetic field of the inductive power transfer system. Eight structure parameters of the proposed shielding are optimized by finite element simulation, in order to reduce the magnetic leakage of the system and improve the utilization rate of shielding materials. In addition, the proposed structure is compared with two types of typical double-layer hybrid shielding from the perspectives of the weight, the coupling coefficient and the magnetic flux leakage. Both simulation and experiment results show that the cost and weight of the proposed shield are about 60% lower than the traditional disk shield. Moreover, the shielding layer proposed in this paper can not only effectively reduce the magnetic flux leakage of the system, but also maintain a high coupling coefficient.
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Bibliography

[1] Zhang Z., Pang H., Georgiadis A., Cecati C., Wireless Power Transfer—An Overview, IEEE Transactions on Industrial Electronics, vol. 66, no. 2, pp. 1044–1058 (2019).
[2] Kalwar K.A., Aamir M., Mekhilef S., Inductively coupled power transfer (ICPT) for electric vehicle charging – A review, Renewable and Sustainable Energy Reviews, vol. 47, pp. 462–475 (2015).
[3] Machura P., Li Q., A critical review on wireless charging for electric vehicles, Renewable and Sustainable Energy Reviews, vol. 104, pp. 209–234 (2019).
[4] Li H., Wang C., Liu Y., Yue R., Research on Single-Switch Wireless Power Transfer System Based on SiC MOSFET, IEEE Access, vol. 7, pp. 163796–163805 (2019).
[5] Zheng J., Wang C., Xia D., Design and analysis of the ferrite air-gapped cores for a resonant inductor[ J], Archives of Electrical Engineering, vol. 67, pp. 579–589 (2018).
[6] Xu H., Wang C., Xia D., Liu Y., Design of Magnetic Coupler for Wireless Power Transfer, Energies, vol. 12, no. 15 (2019).
[7] Christ A., Douglas M.,Nadakuduti J.,Kuster N., Assessing Human Exposure to Electromagnetic Fields from Wireless Power Transmission Systems, Proceedings of the IEEE, vol. 101, no. 6, pp. 1482–1493 (2013).
[8] Ding P., Bernard L., Pichon L., Razek A., Evaluation of Electromagnetic Fields in Human Body Exposed to Wireless Inductive Charging System, IEEE Transactions on Magnetics, vol. 50, no. 2, pp. 1037–1040 (2014).
[9] International Commission on Non-Ionizing Radiation Protection Guidelines for limiting exposure to time-varying electric and magnetic fields (1 Hz to 100 kHz), Health Phys., vol. 99, pp. 818–836 (2010).
[10] Tan L., Elnail K.E.I., Ju M., Huang X., Comparative Analysis and Design of the Shielding Techniques in WPT Systems for Charging EVs, Energies, vol. 12, no. 11 (2019).
[11] Choi S.Y., Gu B.W., Lee S.W., Lee W.Y., Huh J., Rim C.T., Generalized Active EMF Cancel Methods forWireless Electric Vehicles, IEEE Transactions on Power Electronics, vol. 29, no. 11, pp. 5770–5783 (2014).
[12] Zhu Q., Zhang Y., Guo Y., Liao C.,Wang L.,Wang L., Null-Coupled Electromagnetic Field Canceling Coil for Wireless Power Transfer System, IEEE Transactions on Transportation Electrification, vol. 3, no. 2, pp. 464–473 (2017).
[13] Zeng H., Liu Z., Hou Y., Hei T., Zhou B., Optimization of Magnetic Core Structure for Wireless Charging Coupler, IEEE Transactions on Magnetics, vol. 53, no. 6, pp. 1–4 (2017).
[14] Houji L., Chunfang W., Zhihao W., Dan L., Research of shield structure for wireless power transfer system, Advanced Technology of Electrical Engineering and Energy, vol. 38, no. 5, pp. 74–83 (2019).
[15] Stergiou C.A., Zaspalis V., Impact of Ferrite Shield Properties on the Low-Power Inductive Power Transfer, IEEE Transactions on Magnetics, vol. 52, no. 8, pp. 1–9 (2016).
[16] Wen F., Huang X., Optimal Magnetic Field Shielding Method by Metallic Sheets in Wireless Power Transfer System, Energies, vol. 9, no. 9 (2016).
[17] Li J., Huang X., Chen C., Tan L., Wang W., Guo J., Effect of metal shielding on a wireless power transfer system, AIP Advances, vol. 7, no. 5 (2017).
[18] Park H.H.,Kwon J.H.,Kwak S.I., Ahn S., Magnetic Shielding Analysis of a Ferrite Plate with a Periodic Metal Strip, IEEE Transactions on Magnetics, vol. 51, no. 8, pp. 18 (2015).
[19] Park H.H., Kwon J.H., Kwak S.I., Ahn S., Effect of Air-Gap Between a Ferrite Plate and Metal Strips on Magnetic Shielding, IEEE Transactions on Magnetics, vol. 51, no. 11, pp. 1–4 (2015).
[20] Kim H., Song C., Kim D., Jung D.H., Kim I., Kim Y., Kim J., Ahn S., Kim J., Coil Design and Measurements of Automotive Magnetic Resonant Wireless Charging System for High-Efficiency and Low Magnetic Field Leakage, IEEE Transactions on Microwave Theory and Techniques, vol. 64, no. 2, pp. 1–18 (2016).
[21] Kim S., Covic G.A., Boys J.T., Tripolar Pad for Inductive Power Transfer Systems for EV Charging, Transactions on Power Electronics, vol. 32, no. 7, pp. 5045–5057 (2017).
[22] Kim M., Byun J., Lee B.K., Performance Analysis of Magnetic Power Pads for Inductive Power Transfer Systems with Ferrite Structure Variation, Journal of Electrical Engineering and Technology, vol. 12, pp. 1211–1218 (2017).
[23] Budhia M., Boys J.T., Covic G.A., Huang C., Development of a Single-Sided Flux Magnetic Coupler for Electric Vehicle IPT Charging Systems, IEEE Transactions on Industrial Electronics, vol. 60, no. 1, pp. 318–328 (2013).
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Authors and Affiliations

Yun Rui Liu
1
Chunfang Wang
1
Dongwei Xia
1
Rui Yue
1

  1. Qingdao University, China
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Abstract

Machining with tool that have cutting edge radius provides components with high fatigue strength, microhardness of a large surface layer and plastic deformation. Finite element simulations of the cutting process give a better knowledge of the chip generation phenomenon, heat generation in the machining area, stress and temperature field results. This study emphasizes the true importance of the mathematical model that underlies the shape of the tool in the pre-processing steps of finite element analysis. The argument is that its achievement and definition depend on the network difficulty. This research purpose is to perform simulations series of orthogonal machining with different radius and depth of cut. In this way, conclusions on the impact of these variations on the whole cutting process were drawn. The finite element application used is Deform 2D, the Lagrange incremental method and the Johnson-Cook material model. The temperature distribution, stress distribution, von Mises stress distribution, effects on specific tool pressure and wear, and fluctuations in the cutting resistance of the tool tip and C45 workpiece were analyzed.
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Authors and Affiliations

A.B. Pop
1
ORCID: ORCID
A.V. Sandu
2 3
ORCID: ORCID
A. Sachelarie
4
ORCID: ORCID
Mihail Aurel Țîțu
ORCID: ORCID

  1. Technical University of Cluj-Napoca, North University Center of Baia Mare, 62A, Victor Babeș Street, Baia Mare, Romania
  2. Gheorghe Asachi Technical University, Faculty of Materials Science and Engineering, Blvd. D. Mangeron 71, 700050 Iasi, Romania
  3. Romanian Inventors Forum, Str. Sf. P. Movila 3, 700089 Iasi, Romania
  4. Gheorghe Asachi Technical University of Iasi, Faculty of Mechanical Engineering, D. Mangeron 41, 70050, Iasi, Romania
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Abstract

Finite element simulations of structures and structural details require suitable material models. Today there is still a lack of such constitutive material models in timber engineering. Therefore, a perennial research project at the Institute for Mechanics of Materials and Structures at the Vienna University of Technology was performed. In this paper the testing equipment, the experiments, the developed material model and its implementation in finite element software will be explained. One focus of the mentioned project is the acquisition of the mechanical behaviour of biaxially, oblique to fibre direction loaded spruce wood. This enables a better simulation of multiaxial stress states in real timber structures. The applicability of the implemented constitutive model will be demonstrated by means of a nonlinear finite element analysis of a bone-shaped test specimen.
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Authors and Affiliations

Herbert W. Mullner
Martin Fleischmann
Joseph Eberhardsteiner

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