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Stress-strain dependent rutting prediction models for multi-layer structures of asphalt mixtures

INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING 2022年第8期23卷 2728-2745页

作者： deng, Yong Zhang, Yao Shi, Xijun Hou, Shuguang Lytton, Robert L. Texas A&M Univ Zachry Dept Civil & Environm Engn College Stn TX 77843 USA Yangzhou Univ Coll Civil Sci & Engn Yangzhou Jiangsu Peoples R China Texas State Univ Ingram Sch Engn San Marcos TX USA Nanjing Tech Univ Coll Transportat Sci & Engn Nanjing Peoples R China

Since rutting is a major distress in flexible pavements at intermediate and high temperatures, rutting models with concise expressions and satisfying accuracy can have considerable contributions to the pavement design, maintenance and rehabilitation. In this circumstance, two mechanistic-empirical rutting models were proposed in this study. The models were adapted from traditional rutting models and involve advanced mechanical aspects such as strains and stress invariants under moving loads and a yield criterion for asphalt mixtures. This paper includes detailed explanations of model expressions, qualitative comparisons with current models and model applications in an innovative laboratory test. The laboratory test and finite element simulation of asphalt mixtures under moving loads were used to calibrate, validate and check the sensitivity of the proposed models. The results showed the proposed models successfully captured rutting development in asphalt mixtures;they also reasonably predicted rutting behaviors of layered structures under different loading and environmental conditions. In model applications, effects of different factors on material properties, structural strain and stress responses and rutting development were evaluated. Finally, the determination of model parameters in the proposed models was discussed and recommended for further research.

关键词： Rutting multi-layer structures mechanistic-empirical prediction model 3d finite element simulation vertically loaded wheel test

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Flow diversion mechanisms and control methodology in asymmetric spinning of special-shaped multi-wedge belt pulley

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INTERNATIONAL JOURNAL OF AdVANCEd MANUFACTURING TECHNOLOGY 2022年第7-8期119卷 5289-5302页

作者： Xue, Kemin Zhou, Jinliang Yan, Siliang Li, Ping Hefei Univ Technol Sch Mat Sci & Engn Hefei 230009 Peoples R China

A four-procedure spinning forming process for manufacturing special-shaped multi-wedge belt pulley (MWBP) was proposed in this paper, which can be applied on spinning technology to produce special-shaped MWBP with web plate and cylinder. First two procedures for obtaining the preformed blank for toothing were investigated through 3d finite element (FE) simulation and experiment, including the spinning shunting procedure and the spinning flattening procedure. Based on the FE simulation results of the spinning shunting procedure, the change of the effective stress and effective plastic strain, the evolution of metal velocity field, and the plastic flow rules were studied. The asymmetric flow diversion of the blank in different positions was discussed, and volume ratio of the upper part and lower part metal (n) of the special-shaped MWBP affected by different positions. The best distance between the upper end of roller 1 and the blank (M) is 8.38 similar to 8.44 mm verified through the experiment. Moreover, the process optimization by controlling the upper fillet size of roller 1 (r(1)), the feed ratio of the rollers (f), and the friction coefficient (u) was studied by FE simulation. The results show that the n, wall thickness deviation, and ellipticity of the preformed blank for toothing were improved by utilizing the optimized forming parameters and the target parts were formed with high quality through experiments.

关键词： Special-shaped multi-wedge belt pulley Flow diversion Spinning flattening 3d finite element simulation Optimization

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Conceptual method for the detailed analytical calculation of capacitance matrix elements in variable capacitance synchronous machines

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IET ELECTRIC POWER APPLICATIONS 2021年第5期15卷 513-527页

作者： deylami, Fazel Pourmirzaei darabi, Ahmad Shahrood Univ Technol Fac Elect Engn & Robot POB *** Shahrood Iran

This article describes a detailed analytical method for obtaining the capacitance matrix elements in variable capacitance synchronous machines (VCSMs). The analytical modelling approach is performed by introducing a decentralized sinusoidal distribution of the stator/rotor electrodes and involves obtaining the capacitance matrix elements based on the electro motive force distribution in the air gap and calculating the induced electric charge in the stator/rotor electrode surfaces. The proposed analytical formulas are valid for both radial-field and axial-field VCSM structures. The analytical model is evaluated and well verified through analysing a multi-stack axial-field VCSM using 3d finite element simulation. Furthermore, a prototype of the VCSM is manufactured and tested to validate the results obtained from the proposed analytical model and finite element method simulations. Based on the results, the proposed model and analytical formulas are able to accurately estimate the capacitance matrix elements of the VCSMs.

关键词： Numerical analysis capacitance finite element analysis analytical modelling approach finite element method simulations 3d finite element simulation capacitance matrix elements decentralized sinusoidal distribution variable capacitance synchronous machines Numerical approximation and analysis radial-field VCSM structures detailed analytical method induced electric charge stators Protection apparatus axial-field VCSM structures finite element analysis rotors air gaps

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design, Manufacture and Performance Evaluation of HTS Electromagnet Wound by YBCO Tape

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IEEE TRANSACTIONS ON APPLIEd SUPERCONdUCTIVITY 2021年第8期31卷 1页

作者： Li, Wenlong Zhang, Wenyue Fang, Jin Fang, Xinyu Yang, Song Zhang, Xinghua Zhou, Wenwu Beijing Jiaotong Univ Sch Elect Engn Beijing 100044 Peoples R China CRRC Zhuzhou Locomot Co Ltd Maglev Syst Res Inst Upton Zhuzhou 412001 Peoples R China Hunan Lingxiang Maglev Technol Co Ltd Changsha 410008 Peoples R China

Heat generation and serious energy consumption of normal-conductive suspension electromagnets influence the performance and stability of suspension systems. With the development of second generation (2G) high temperature superconducting (HTS) technologies, HTS suspension electromagnets are being considered for energy saving purpose. In this paper, a suspension system with three suspension electromagnets is designed, which is comprised of two normal-conductive suspension electromagnets and a 2G-HTS suspension electromagnet. A three-dimensional (3d) electromagnetic field simulation based on finite element method (FEM) is carried out, and the force test platform of suspension electromagnet is built for performance evaluation of the HTS suspension electromagnet. The experimental results show that the current of HTS suspension electromagnet is steady loaded from 0 A to 70 A under 77 K working conditions, with the suspension force meet the requirements. This work provides a certain theoretical and practical foundation for the future superconducting suspension projects.

关键词： YBCO tape HTS suspension electromagnet 3d finite element simulation suspension test

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Towards three dimensional aspects of plasticity-induced crack closure: A finite element simulation

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INTERNATIONAL JOURNAL OF FATIGUE 2022年 163卷

作者： Paysan, Florian Breitbarth, Eric German Aerosp Ctr DLR Inst Mat Res Cologne Germany

The mutual interactions between intrinsic (damage) and extrinsic (shielding) mechanisms are essential for understanding fatigue crack growth in ductile materials. In the latter case, plasticity-induced crack closure is the dominating retardation mechanism in the Paris regime. The transition between plane strain and plane stress states leads to a locally different fracture surface contact, which is difficult to access during experiments. In this work, plasticity-induced crack closure under constant amplitude loading of an AlCu4Mg (AA2024) aluminium sheet material is studied from a three-dimensional perspective. An elastic-plastic 3d finite element model of an M(T)160 specimen with a bilinear isotropic hardening model is used to study the evolution of plasticity during fatigue crack growth. Cyclic crack propagation is simulated with the releasing-constraint method. In the results, plasticity-induced crack closure is present up to a load ratio R = 0.3. detailed investigations of the contact pressure distributions indicate a strong dependence on the stress intensity factors and the sheet thicknesses. The contact pressure distributions on the fracture surface can be divided into three characteristic regions. Near the plastic zone, plastic energy is still induced during the unloading process after the crack is already closed. However, the crack surface contact does not affect the shape of the plastic zone. Additionally, further plastic energy accumulates in the plastic wake region during crack closure within subsequent load cycles, described here as cyclic plastic wake. In summary, the finite element model can reproduce the major features of fatigue crack closure like Kop or Kcl and the three-dimensional and load-dependent evolution of plasticityinduced crack closure.

关键词： Plasticity -induced crack closure 3d finite element simulation Fatigue crack growth Fracture mechanics

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Three-dimensional finite element simulation of magnetic-mechanical-electrical coupling in layered cylindrical multiferroic structures

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MECHANICS OF MATERIALS 2022年 175卷

作者： Song, Ruiyu Zhang, Juanjuan Weng, George J. Lanzhou Univ Coll Civil Engn & Mech Key Lab Mech Environm & Disaster Western China Minist Educ China Lanzhou 730000 Gansu Peoples R China Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xian 710049 Shanxi Peoples R China Rutgers State Univ Dept Mech & Aerosp Engn New Brunswick NJ 08903 USA

The excellent magnetoelectric (ME) performance of multiferroic structures under room temperature has inspired a wide range of applications in smart devices like energy collectors, ME transducers, neo-antennas, etc. Starting from the constitutive equations of ferroelectric and ferromagnetic materials, a three-dimensional (3d) finite element simulation model was set up to investigate the ME behaviors of the cylindrical structures consisting of Terfenol-d and lead zirconate titanate (PZT). Then the solid mechanical module, electrostatic module and the magnetic module are coupled to calculate the mechanical, electrical and magnetic properties of the components and the structures. The calculated ME coefficients were in good agreement with the experimental data. The results show that P/T and T/P structures reach the maximum of ME coefficients at different bias magnetic fields, approximately 2.5 x 104 A/m for P/T structure and 4.8 x 104 A/m for T/P structure. The maximum value of alpha E31 in the P/T structure is twice that of T/P structure. Moreover, the distribution of magnetic, mechanical, and electrical fields of the composites are also analyzed. The results show that the magnetization of the ferromagnetic material exhibits a non-uniform distribution at low magnetic field, the stress concentration occurs at the Terfenol-d and PZT interface, and the electric potential of piezoelectric material is non-uniform in the plane. Finally, the influence of the interface characteristics on the ME effect is also studied. It is found that, the thicker the interface and the lower the Young's modulus, then the smaller the corresponding ME coefficient for the P/T structure.

关键词： Layered cylindrical multiferroic structures Magnetoelectric effect Field distribution characteristics 3d finite element simulation

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Seismic damage evaluation of an entire underground subway system in dense urban areas by 3d FE simulation

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TUNNELLING ANd UNdERGROUNd SPACE TECHNOLOGY 2020年 99卷 103351-000页

作者： Li, Wenting Chen, Qingjun Shanghai Normal Univ Coll Civil Engn Shanghai 201418 Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Engn Shanghai 200092 Peoples R China

Underground structures often pass beneath high-rise buildings or are located close to them in megacities. Given complex site-city interactions, conventional earthquake engineering practices may leave megacities in seismically prone areas in potential danger. Rather than focusing purely on the interaction between soil and either surface structures or underground structures, this study aims to explore the earthquake-induced hazard of a dense urban area with an entire subway station, two long subway tunnels and 36 fully modeled high-rise piled frame buildings. The study is conducted through the 3d fully coupled dynamic analysis in both the time and frequency domains, emphasizing the influence of aboveground buildings on underground structures. The results reveal that the existence of aboveground buildings generally decreases the station's response and can either increase or decrease the subway tunnel's responses. The presence of either aboveground structures or underground structures affects the wavefield and in turn the responses of adjacent structures, highlighting the importance of considering soil-city interactions. The station is most dangerous at the columns' bottoms. The existence of subway stations and tunnels increases the nearby peak ground accelerations.

关键词： Soil-structure interaction (SSI) Site-city interaction (SCI) Subway station Tunnel Earthquake 3d finite element simulation

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Research on deformation law and mechanism for milling micro thin wall with mixed boundaries of titanium alloy in mesoscale

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THIN-WALLEd STRUCTURES 2019年 144卷

作者： Yi, Jie Wang, Xibin Jiao, Li Xiang, Junfeng Yi, Fengyan Shandong Jianzhu Univ Sch Mech & Elect Engn Jinan 250101 Shandong Peoples R China Beijing Inst Technol Key Lab Fundamental Sci Adv Machining Beijing 100081 Peoples R China Northwestern Polytech Univ Sch Civil Aviat Suzhou 215400 Peoples R China Shandong Jiaotong Univ Automot Engn Coll Jinan 250023 Peoples R China

At mesoscale, the blade of micro impeller with Ti-6Al-4V titanium alloy (micro thin wall with mixed boundaries) is a thin-walled structure, characterized by small size, low stiffness, high surface precision, complex boundaries, and difficult-to-control machining deformation. To control and reduce the deformation of micro thin wall, it is necessary to study the micro-deformation mechanisms during milling micro thin-wall parts. In side milling of micro thin wall with mixed boundaries, the micro thin wall suffers from dynamic alternating forces, and the deformation modes are complex, so the direct and accurate theoretical modelling is difficult to make. Since the feed speed in milling micro thin wall is less, the small deformation of micro thin wall can be described based on the flexure deformation model of the thin plate subjected to elastic loadings. Firstly, accompanied by the reciprocal theorem of work for a curved thin plate, Kirchhoff-Love small deformation model of micro thin wall is used to establish the deformation equation and boundary conditions of micro thin wall with mixed boundaries under concentrated milling forces. Thus, the obtained boundary conditions are mainly applied to the subsequent finite element simulation of three-dimensional milling deformation of micro thin wall. Then a three-dimensional deformation simulation of the micro thin wall under different milling parameters is carried out by considering the micro-walled structure, material elasto-plastic constitutive model, the stiffness and geometric structure of micro milling tools in finite element method. In the workpiece constitutive modelling, considering the strain gradient plastic model in micro milling of Ti-6Al-4V titanium alloy, the workpiece plastic constitutive model is modified by introducing the intrinsic characteristic length of the material to describe the size effects in mesoscale micro milling. Finally, a series of the corresponding experiments on the milling of titanium alloy mi

关键词： Mesoscale Ti-6Al-4V titanium alloy Micro thin wall Micro milling deformation 3d finite element simulation

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Characterization of Surface Cracks Using Eddy Current NdT simulation by 3d-FEM and Inversion by Neural Network

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APPLIEd COMPUTATIONAL ELECTROMAGNETICS SOCIETY JOURNAL 2016年第2期31卷 187-194页

作者： Helifa, B. Feliachi, M. Lefkaier, I. K. Boubenider, F. Zaoui, A. Lagraa, N. Univ Laghouat Lab Phys Mat BP 37G Laghouat 03000 Algeria Univ Nantes LUNAM CRTT IREENAIUT BP 406 F-44602 St Nazaire France USTHB Lab Phys Mat Bab Ezzouar 016000 Alger Algeria EMP BP 17 Bordj El Bahri 16100 Alger Algeria Univ Laghouat Lab Informat & Math BP 37G Laghouat 03000 Algeria

In this work, we suggest an approach of signal inversion from sensors used in eddy current (EC) nondestructive testing (NdT). The aim is to characterize surface cracks from the EC signal. A methodology that combines 3d finite element (FEM) simulation and a data inversion by neural networks (NN) is proposed. We show that the use of a set of numerical measurements representing the EC signature of surface crack enables to remedy of the unicity problem. The obtained results show that the developed approach leads to the quantification of the crack.

关键词： 3d finite element simulation eddy current NdT neural network surface cracks

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NUMERICAL STUdY OF SOLId EXPANdABLE TUBULAR TECHNOLOGY

SOCAR PROCEEDINGS

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SOCAR PROCEEdINGS 2016年第1期 25-33页

作者： Pei, J. China Coal Technol & Engn Grp Corp Xian Res Inst Xian Shaanxi Peoples R China

A 3d finite element method is used to analyze the expansion process of solid expandable tube. The tube is modeled as a deformable body with plastic kinematic hardening material behavior. It is found that expansive force increases with the increase. of friction coefficient, also there exists optimal mandrel semi-cone angle and sizing zone length to make expansive force to be minimal. Reasonable large friction coefficient helps to reduce residual stress, and the residual stress shows a quadratic parabola relation with semi-cone angle. With the increase of friction coefficient and decrease of sizing zone length, the thickness variation of tube increases and length variation of tube decreases. Finally, a typical expansion simulation of rotating and not rotating the mandrel is analyzed, result shows that, when using a rotating mandrel, expansive force is 14.4% less than non-rotating mandrel. (C) 2016 "OilGasScientificResearchProject" Institute. All rights reserved.

关键词： Solid expandable tubular technology 3d finite element simulation Expansive force Residual stress Tubular thickness/length variation

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