盘型悬式绝缘子瓷件的应力分析和结构优化

为减少盘型悬式绝缘子断裂事故的发生,研究了绝缘子瓷件的应力水平以及结构的优化.建立盘型悬式绝缘子的有限元模型以计算绝缘子受拉伸作用下的应力分布特性,以及在不同拉力方向的作用下,绝缘子瓷件上的应力情况.采用有限元和机器学习相结合的方法对绝缘子的结构进行优化.结果表明:在拉力作用下,瓷件与水泥胶合剂的接触面部分分离,导致绝缘子瓷件中部壁面的应力水平较高,拉力方向与绝缘子轴线的夹角越大,瓷件上的应力水平越高.在有限元计算的基础上,利用机器学习方法,对绝缘子的结构参数进行优化设计,得到了最优结构参数,最优结构较原始结构应力水平降低了30%,并对最优结构进行有限元计算验证,发现两者误差率仅为0.644%,结果可靠且优化效果显著.在绝缘子的胶装过程中,应增强胶装强度,在绝缘子的安装中,应尽量减小绝缘子的受拉方向与轴线的夹角,以有效增加绝缘子的工作寿命.结构优化得到的最优参数可以为结构设计提供理论指导和技术支持.     

硅纳米线拉伸与熔化行为的原子模拟

Molecular dynamics simulations with Stillinger-Weber potential are used to study the tensile and melting behavior of single-crystalline silicon nanowires（SiNWs）.The tensile tests show that the tensile behavior of the SiNWs is strongly dependent on the simulation temperature,the strain rate,and the diameter of the nanowires.For a given diameter,the critical load significantly decreases as the temperature increases and also as the strain rate decreases.Additionally,the critical load increases as the diameter increases.Moreover,the melting tests demonstrate that both melting temperature and melting heat of the SiNWs decrease with decreasing diameter and length,due to the increase in surface energy.The melting process of SiNWs with increasing temperature is also investigated.