带预应力套箍的避雷针法兰节点抗风性能研究

RESEARCH ON WIND RESISTANCE OF FLANGE JOINTS OF LIGHTNING ROD WITH PRESTRESSED HOOPS

针对输电塔避雷针破坏问题,基于减小高强螺栓应力幅值及节点双重防护的理念提出了避雷针与输电塔结构之间的新型连接方式,即钢绞线加强法兰节点。利用有限元软件WORKBENCH建立了有限元模型,研究了钢绞线预拉力20 kN、不同风速下两种避雷针的应力与位移,分别以风速5,15,30,50 m/s为参数,分析流体对避雷针结构的压应力云图、流线矢量图、应力及位移值。并对不同荷载工况下避雷针的应力响应及位移响应与实测值进行对比。结果表明:在相同风速荷载作用下,避雷针受到流体压强相同,且避雷针与人字柱连接处应力最大;与常规的连接方式相比,新型连接方法能显著降低顶部位移,有效降低连接螺栓的应力峰值,保证避雷针安全使用,且风速越大,效果越明显。

For the failure of lightning rod in transmission tower,an innovation connection between the lighting rod and the transmission tower was proposed based on the concept of reducing the stress amplitude of high-strength bolts and realizing double protection,namely steel strand reinforced flange joint. The finite element model was established by using the finite element software WORKBENCH. The stress and displacement were studied on two kinds of joints for lightning rods at different wind speeds and steel strand pretensions of 20 k N. The stress nephogram,streamline vector diagram,stress and displacement response of the lightning rod structure caused by fluid were expressed under the wind velocity of 5 m/s,15 m/s,30 m/s,and 50 m/s. The contrastive analysis was carried on the stress and displacement response of the lightning rod with the measured values under different loading conditions. The analysis results showed that the lightning rod was subjected to the same fluid pressure under the same load. The stress was the largest at the connection between the lightning rod and the herringbone column. The research results showed that the new lightning rod could significantly reduce the peak values compared with the conventional lightning rod. It was more effectively in reducing the stress peak values on the connecting bolts so as to ensure the safe use of the lightning rod.The higher the wind speed,the more obvious the effect.