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Applied Mathematics and Mechanics(English Edition) 2022年第5期43卷 689-708页

作者： yongbin WANG huadong yong Youhe ZHOU Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China

For the accurate prediction of the effective thermal conductivities of the twisted multi-filamentary superconducting strand,a two-step homogenization method is adopted.Based on the distribution of filaments,the superconducting strand can be decomposed into a set of concentric cylinder layers.Each layer is a two-phase composite composed of the twisted filaments and copper matrix.In the first step of homogenization,the representative volume element(RVE)based finite element(FE)homogenization method with the periodic boundary condition(PBC)is adopted to evaluate the effective thermal conductivities of each layer.In the second step of homogenization,the generalized self-consistent method is used to obtain the effective thermal conductivities of all the concentric cylinder layers.The accuracy of the developed model is validated by comparing with the local and full-field FE simulation.Finally,the effects of the twist pitch on the effective thermal conductivities of twisted multi-filamentary superconducting strand are studied.

关键词： superconducting strand multi-filamentary two-step homogenization effective thermal conductivity

Numerical simulation of the mechanical behavior of superconducting tape in conductor on round core cable using the cohesive zone model

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Applied Mathematics and Mechanics(English Edition) 2023年第9期44卷 1511-1532页

作者： Shengyi TANG Xubin PENG huadong yong Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China Faculty of Civil Engineering and Mechanics Jiangsu UniversityZhenjiang 212013Jiangsu ProvinceChina

Cables composed of rare-earth barium copper oxide(REBCO)tapes have been extensively used in various superconducting devices.In recent years,conductor on round core(CORC)cable has drawn the attention of researchers with its outstanding current-carrying capacity and mechanical properties.The REBCO tapes are wound spirally on the surface of CORC cable.Under extreme loadings,the REBCO tapes with layered composite structures are vulnerable,which can lead to degradation of critical current and even quenching of superconducting devices.In this paper,we simulate the deformation of CORC cable under external loads,and analyze the damage inside the tape with the cohesive zone model(CZM).Firstly,the fabrication and cabling of CORC are simulated,and the stresses and strains generated in the tape are extracted as the initial condition of the next step.Then,the tension and bending loads are applied to CORC cable,and the damage distribution inside the tape is presented.In addition,the effects of some parameters on the damage are discussed during the bending simulations.

关键词： high temperature superconducting(HTS)tape superconducting cable finite element simulation cohesive zone model(CZM) damage

Mechanical Analysis of a No-insulation Pancake Coil with the Overband During a Quench

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Acta Mechanica Solida Sinica 2022年第3期35卷 357-366页

作者： Donghui Liu Yunkai Tang Dongke Li huadong yong Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

The no-insulation(NI)winding approach can remarkably improve the thermal stability of high-temperature superconducting coil.However,mechanical issues have gradually become a key factor to block the development of NI magnets in recent years.This paper mainly analyzes the effect of the overband on the mechanical behaviors of an NI coil during a quench.A numerical model including a quench model combined with a three-dimensional homogeneous mechanical model is employed to study the change of stress in the coil without and with the over band during a local quench.The results show that the overband has an obvious effect on the stress distribution as the heater is located at the outer turn of the coil.Meanwhile,the values of stress in the coil are also affected by the overband.Moreover,the effects of the thickness of the overband and the location of the heater on the mechanical behaviors of the coil are also discussed.It is worth noting that the overband can remarkably reduce the hoop and axial tensile stresses of the coil during a quench。

关键词： No-insulation coil Overband Quench Stress

Estimation of critical current density of bulk superconductor with artificial neural network

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Superconductivity 2023年第3期7卷 34-45页

作者： Gangling Wu huadong yong Key Laboratory of Mechanics on Disaster and Environment in Western China The Ministry of Education of ChinaLanzhou UniversityLanzhouGansu 730000People’s Republic of China Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhouGansu 730000People’s Republic of China

In the applications of superconducting materials,the critical current density J_(c)(B)is a crucial performance parameter.The conventional method of measuring J_(c)(B)of bulk superconductor is magnetization method.However,there are errors in the estimation of J_(c)(B)in the lower field,and the estimation is not applicable in the region where the magnetic field reverses.In this paper,J_(c)(B)of the bulk superconductor is determined by the hysteresis and magnetostriction loops with artificial neural network(ANN),respectively.Compared with double‐output ANN,the critical current density obtained by single‐output ANN is more accurate.Finally,the prediction results given by the hysteresis and magnetostriction loops are discussed.

关键词： Critical current density ANN Kim model Hysteresis loop Magnetostriction loop Bulk superconductor

Electromagnetic-thermal-mechanical characteristics with active feedback control in a high-temperature superconducting noinsulation magnet

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Science China(Physics,Mechanics & Astronomy) 2022年第9期65卷 92-103页

作者： Donghui Liu Dongke Li Weiwei Zhang huadong yong Youhe Zhou Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhou 730000China Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhou 730000China

High-temperature superconducting(HTS) magnets consisting of no-insulation(NI) double-pancake coils(DPCs) with high thermal stability have been proposed for use in the preparation of high-field magnets. However, increased ramp time is a known disadvantage of the NI approach. To solve this problem, a proportional and integral(PI) active feedback control has been proposed in the charging experiments of the NI magnet. In this study, the electromagnetic-thermal-mechanical characteristics of an NI magnet with and without PI are analyzed to ensure the safety and reliability of PI control. Due to the increase in the radial current of the magnet, the turn-to-turn loss energy of the magnet with PI is more than twice that without PI. However, the magnetization loss energy of the magnet has a small difference with and without PI. It can be also found that the NI magnet with PI has a large temperature rise, and thus it has a low thermal stability margin. Moreover, in the high field, the hoop stress and hoop strain peaks of a magnet with PI are larger than those without PI. Thus, PI control can induce a relatively high risk of mechanical damage in the applications of NI magnets.

关键词： no-insulation magnet active feedback control loss energy temperature rise strain and stress

Fatigue behaviors and damage mechanisms for Nb_(3)Sn triple-helical structure at liquid nitrogen temperature

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Superconductivity 2023年第4期8卷 34-42页

作者： Lang Jiang Zhiwei Zhang Zhen Yu Jun Zhou huadong yong Xingyi Zhang Key Laboratory of Mechanics on Disaster and Environment in Western China Attached to the Ministry of Education of China Lanzhou UniversityLanzhouGansu 730000PR China Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhouGansu 730000PR China

Nb_(3)Sn triple‐helical structure is the elementary structure in the superconducting cable of ITER magnets and undergoes prolonged fatigue loading in extreme environments leading to serious damage degradation.In this paper,the fatigue behaviors of the Nb_(3)Sn triple‐helical structure have been investigated by the strain cycling fatigue experiments at liquid nitrogen temperature.The results indicate that Nb_(3)Sn triple‐helical structures with short twist‐pitches possess excellent fatigue damage resistance than that of long twist‐pitches,such as longer fatigue life,slower damage degradation,and smaller energy dissipation.Meanwhile,a theoretical model of damage evolution has been established to reveal the effects of twist‐pitches on fatigue properties for triplehelical structures,which is also validated by the present experimental data.Furthermore,one can see that the Nb_(3)Sn superconducting wires in a triple‐helical structure with the shorter twist‐pitches have a larger elongation of helical structure and less cyclic deformation,which can be considered as the main mechanism of better fatigue damage properties for the triple‐helical structures during the strain cycling processes.These findings provide a better understanding of the fatigue properties and damage mechanisms for Nb_(3)Sn triple‐helical structures in superconducting cables of ITER magnets.

关键词： Nb_(3)Sn triple‐helical structures Fatigue damage Twist‐pitches Liquid nitrogen temperature Theoretical model

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基于卡氏第二定理求解细长螺旋杆件的位移

力学与实践 2024年第2期46卷 443-446页

作者：雍华东兰州大学土木工程与力学学院

由于具有较为优异的力学性能，螺旋结构的细长杆件在工程中得到了广泛的应用。在拉伸及弯曲载荷作用下，螺旋杆件自身较为特殊的结构导致其变形规律较为复杂。本文基于螺旋杆件的应变能及材料力学的卡氏第二定理，得到了拉伸及横向载荷... 详细信息

由于具有较为优异的力学性能，螺旋结构的细长杆件在工程中得到了广泛的应用。在拉伸及弯曲载荷作用下，螺旋杆件自身较为特殊的结构导致其变形规律较为复杂。本文基于螺旋杆件的应变能及材料力学的卡氏第二定理，得到了拉伸及横向载荷作用下螺旋杆件的位移，所得解析结果与有限元结果一致。螺旋杆件位移的求解可以作为材料力学基本内容的拓展，加强学生对相关知识点的理解和掌握。

关键词：螺旋杆件位移卡氏第二定理

Damage Analysis of Superconducting Composite Wire with Bridging Model

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Acta Mechanica Solida Sinica 2018年第1期31卷 19-31页

作者： Xubin Peng huadong yong Youhe Zhou Key Laboratory of Mechanics on Environment and Disaster in Western China The Ministry of Education of China Department of Mechanics and Engineering Sciences College of Civil Engineering and Mechanics Lanzhou University

The multi-filamentary Bi2Sr2CaCu2O8＋x （Bi-2212） round wires are made of super- conducting filaments, metal Ag and Ag alloy, which are typical composite structure. Since the filament is brittle, there are various defects and cracks in the Bi-2212 round wire after heat treat- ment. In this paper, we assume that the filaments in the wire are uniformly arranged. Adopting the bridging model which is often used in the fiber-reinforced composite, we calculate the ulti- mate strength of the round wire. The effects of the volume fraction, elastic modulus and interface shear strength are discussed in detail.

关键词： Bi-2212 composite Crack Bridging model Stress intensity factor Ultimate ten-sile strength

Dynamic analysis and active control of hard-magnetic soft materials

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International Journal of Smart and Nano Materials 2021年第4期12卷 429-449页

作者： Zhencai Xing huadong yong Key Laboratory of Mechanics on Disaster and Environment in Western China Ministry of Education of ChinaLanzhou UniversityLanzhouPeople’s Republic of China Department of Mechanics and Engineering Sciences College of Civil Engineering and MechanicsLanzhou UniversityLanzhouPeople’s Republic of China

The hard-magnetic soft materials which can sustain high residual magnetic flux density gradually attract the attention of researchers because of potential applications in soft robotics and biomedical fields.In this work,we focus on the dynamic response of hardmagnetic soft materials.The dynamic motion equations are derived by the Euler-Lagrange equation.The effects of the aspect radio on the nonlinear vibration of the hard-magnetic soft cuboid under the force and applied magnetic fields in different directions are investigated.The amplitude-frequency curves demonstrate that the aspect ratio also has an influence on the frequency and amplitude of the primary resonance.Moreover,to eliminate undesired vibration responses,the PID controller is applied to the vibration of the hardmagnetic soft materials,and the desired results can be obtained.

关键词： Hard-magnetic soft materials aspect ratio nonlinear vibration active control

EFFECT OF MAGNETIC NANOPARTICLES ON THE MECHANICAL PROPERTIES OF TYPE-II SUPERCONDUCTORS

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Acta Mechanica Solida Sinica 2014年第1期27卷 65-72页

作者： Chenguang Huang huadong yong Youhe Zhou Key Laboratory of Mechanics on Environment and Disaster in Western China The Ministry of Education of China and Department of Mechanics and Engineering Sciences School of Civil Engineering and MechanicsLanzhou University

In this paper, the effect of magnetic nanoparticles on the mechanical properties of a type-II superconductor is investigated both theoretically and numerically. Magnetic part of the pinning force associated with the interaction between a finite-size spheroidal magnetic inclusion and an Abrikosov vortex is calculated in the London approximation. It is found that the size and shape of magnetic nanoparticles result in different enhancements of vortex pinning in large-k type-II superconductors. Meanwhile, the screening current induced by a magnetic spheroid suffer the action of Lorentz force, which will lead to prestress in the superconductor, so further numerical calculations are needed to explore the interaction between the spheroidal magnetic particle and superconductor. The distribution of displacement, stress and strain in the superconductor are finally obtained. It is shown that different sizes and shapes of nanoparticles also can change the distributions of these quantities.

关键词： magnetic nanoparticles spheroidal inclusion pinning force stress distribution type-II superconductor