超导线圈低/变温热膨胀系数预测与实验  

Prediction and experiment of thermal expansion coefficient of superconducting coil at low/variable temperature

作　　者：金乘慧 吴北民[2] 何天虎[1] 关明智[2,1] Jin Chenghui;Wu Beimin;He Tianhu;Guan Mingzhi(School of Science,Lanzhou University of Technology,Lanzhou 730050,China;Institute of Modern Physics,Chinese Academy of Sciences,Lanzhou 730000,China)

机构地区：[1]兰州理工大学理学院,兰州730050 [2]中国科学院近代物理研究所,兰州730000

出　　处：《低温与超导》2023年第1期8-14,共7页Cryogenics and Superconductivity

基　　金：国家自然科学基金(12172357);中国科学院青年创新促进会(2019404);甘肃省自然基金重点项目(2022-22JR5RA127);广东省基础与应用基础研究基金联合基金重点项目(2022B1515120051)资助。

摘　　要：为表征超导线圈低/变温环境热膨胀系数,首先基于细观力学有限元方法建立了超导线圈代表性体积元模型,并利用多项式函数赋予材料属性进一步完成低/变温环境热膨胀系数有限元预测,通过复合律公式计算出理论值验证了有限元模型的准确性。其次,基于应变片测量热膨胀系数的原理,搭建了超导线圈低/变温热膨胀系数测量系统,最后,针对常规材料热膨胀系数进行了实验测量,验证了搭建系统的可靠性。进一步地,基于上述基础表征研究,开展了超导线圈相关低温测量的实验研究,得到了极端低/变温环境下超导线圈热应变、热膨胀系数与温度之间明显的非线性关系,且实验测试结果与理论值吻合良好。该数值模型、实验方法与测试系统的成功发展一方面丰富了极端环境下材料热膨胀系数的表征方法,另一方面,将为我国各类大型超导磁体结构设计、制备与实验提供重要参数与热-力学基础测试平台。In order to characterize that thermal expansion coefficient of the superconducting coil in low/variable temperature environment,a representative volume element(RVE)model of the superconducting coil was established based on the micromechanical finite element method,and the finite element prediction of the thermal expansion coefficient of the superconducting coil in low/variable temperature environment was further completed by endowing material properties with a polynomial function.The accuracy of the finite element model was verified by calculating the theoretical value through a compound law formula.Based on the principle of measuring thermal expansion coefficient with strain gauge,a measuring system for low/variable temperature thermal expansion coefficient of superconducting coil was built.The thermal expansion coefficient of conventional materials was measured experimentally,the reliability of the system was verified.Furthermore,based on the above basic characterization research,the experimental research on cryogenic measurement of superconducting coil was carried out,and the obvious nonlinear relationship between thermal strain and thermal expansion coefficient of superconducting coil and temperature under extremely low/variable temperature environment were obtained,and the experimental measurement results are in good agreement with the theoretical values.The successful development of the numerical model,the experimental method and the test system not only enriches the characterization methods of the thermal expansion coefficient of materials under extreme environments,but also provides important parameters and a thermal-mechanical basic test platform for the design,preparation and experiment of various large-scale superconducting magnet structures in China.

关 键 词：超导线圈 代表性体积元 有限元法 热膨胀系数 低/变温 

分 类 号：O343.6[理学—固体力学]