含缺陷超导体在场冷励磁下的力学特性研究  

Mechanical properties of defective superconductors under field cold excitation

作　　者：姜峰[1] 侯家宝 周文海 梁瑞[1] Jiang Feng;Hou Jiaba;Zhou Wenhai;Liang Rui(Lanzhou University of Technology,Lanzhou 730050,China;Key Laboratory of Mechanics on Environment and Disaster in Western China,Ministry of Education of China,Lanzhou University,Lanzhou730000,China)

机构地区：[1]兰州理工大学石油化工学院,兰州730050 [2]兰州大学西部灾害与环境力学教育部重点实验室,兰州730000

出　　处：《低温与超导》2022年第5期12-18,51,共8页Cryogenics and Superconductivity

基　　金：国家自然科学基金(5156010);甘肃省自然科学基金(B061709)资助。

摘　　要：对含有中心孔洞缺陷的长圆柱状超导体在场冷却(FC)励磁过程中产生的磁通钉扎力学特性进行了研究。考虑了临界电流密度非均匀性和粘性磁通流动效应的影响,得出了孔洞大小、临界电流密度非均匀系数及外场励磁速度这三种不同取值情况下的应力分布曲线,通过定义应力集中系数σ_(pm)/σ_(0)分析了孔洞的应力集中效应。结果表明:场冷却时,超导结构内的体力全为拉伸状态,并且相同磁场条件下的环向应力σ_(θ)(r)始终是径向应力σ_(r)(r)的2倍左右;孔洞半径a/R、临界电流密度非均匀系数m以及外磁场励磁速度db_(a)/dt的变化均会引起超导体内应力峰值σ_(r,max)(r)和σ_(θ,max)(r)的增大;当外磁场B_(a)/B_(p)在较小范围取值时,a/R和m的变化对应力集中具有显著影响。In this paper,the mechanical characteristics of magnetic flux pinning generated by long cylindrical superconductors with central hole defects during field cooling(FC)excitation were studied.The effects of critical current density non-uniformity and viscous flux flow were also considered,and the stress distribution curves were derived for three different values of hole size,critical current density non-uniformity coefficient and viscous flux flow rate.The stress concentration effect of the hole was analyzed by defining the stress concentration factorσ_(pm)/σ_(0).The results show that the physical force in the superconductor is all tensile when the field is cooled,and the circumferential stress is always about twice as high as the radial stress under the same magnetic field;the empty hole radius a/R,the critical current density non-uniformity coefficient m,and the excitation velocity db_(a)/dt of the external magnetic field will cause an increase in the peak internal stressesσ_(r,max)(r)andσ_(θ,max)(r)in the superconductor.The smaller the value of the external magnetic field B_(a)/B_(p),the more obvious the influence on the stress concentration effect.

关 键 词：高温超导体 缺陷 应力分布 应力集中效应 临界电流密度 磁通流动效应 

分 类 号：TM265[一般工业技术—材料科学与工程]