新型定位格架夹持结构的疲劳特性研究

Research on Fatigue Performance of Newly Developed Supporting Structure of Spacer Grid

针对新型定位格架夹持结构及其疲劳问题,利用有限元分析手段评估其运行条件下的应力状态,并开展弹簧疲劳特性实验,分析疲劳失效特性及裂纹萌生位置。结果表明,该夹持结构的弹簧疲劳失效大致经历载荷降低与快速失效等阶段;由于弹簧支撑腿的作用,失效后弹簧依然维持一定的载荷,约为名义载荷的0.42倍;同时,弹簧结构的疲劳与裂纹萌生位置不仅与应力值有关,还受载荷传递关系的影响。有限元数值模拟可以作为定位格架夹持结构设计与优化的有效辅助手段,并可初步判断其疲劳失效的位置。

Aiming at the innovative supporting structure and its fatigue performance,this paper evaluates the stress state under its operating conditions by means of finite element analysis,and carries out the spring fatigue test to analyze the fatigue failure characteristics and crack initiation locations.The results show that the spring fatigue failure of the supporting structure roughly goes through the stages of load reduction and rapid failure.Due to the support legs of the spring,the spring still maintains a certain load after failure,which is about 0.42 times of the nominal load.The fatigue and crack locations are not only determined by the stress value,but also by the transferring feature of load.The finite element model is an effective method for the design and optimization of the supporting structure of spacer grid,and can preliminarily identify the location of fatigue failure.