摘要
对NbTi/Cu超导股线、绞线开展了一系列常温力学特性实验研究,包括准静态加卸载、芯丝裂纹扩展及轴向疲劳。实验发现:超导股线加载过程具有明显的阶段性,经过初始加卸载循环"锻炼"后,残余应变不随卸载应力增加而增加;疲劳前期芯丝内部无裂纹,疲劳后期裂纹呈指数型增长直至最终破坏;绞线杨氏模量、疲劳寿命均与扭转节距有关。疲劳过程中,采用循环周期内耗散能定性评估材料内部损伤程度。
We carried out a series of room temperature mechanical experiments of praetieal superconducting NbTi strand and twisted triplet, including eyelie loading - unloading test, crack growth and axial fatigue. The experiments reveal that the loading proeess has two stages and residual strain remains almost the same with the increasing of unloading stress after the first loading - unloading mechanical ＂training＂ ; there is no crack in the early stage of the fatigue and crack appears in the later stage and growth exponentially until fraeture ; young＇ s modulus and fatigue life are related to the twist piteh. We can use energy dissipation to qualitative assessment material damage.
出处
《低温与超导》
CAS
北大核心
2016年第12期36-40,46,共6页
Cryogenics and Superconductivity
基金
国家自然科学基金委面上项目(11202089)
国家磁约束核聚变能源发展计划ITER专项(2013GB110001)
全国优博专项基金(201135)资助
关键词
NbTi股线
加卸载
裂纹扩展
疲劳寿命
耗散能
NbTi supereondueting strand, Cyclic loading and unloading test, Crack growth, Fatigue life, Dissipated energy
