基于向量式有限元的拱梁组合桥吊杆断裂动力分析

Dynamic Analysis for Suspender Fracture of An Half-through Arch Beams Combined System Bridge by Vector Form Intrinsic Finite Element Method

为研究单根吊杆失效对拱梁组合桥产生的不利效应,该文采用向量式有限元进行了拱梁组合桥单根吊杆断裂后的动力分析。文中首先调整了向量式有限元中预应力索单元的失效判据,提出了吊杆逐渐断丝失效模型并加以验证,最后采用自编向量式有限元程序,对下承式拱梁组合桥的单片拱肋进行了不同吊杆失效模式下的模拟。得到了各吊杆内力和系梁位移的动力响应曲线。结果表明:利用向量式有限元能够准确的进行断索全过程动力分析,其中,吊杆突然断裂时对相邻吊杆的影响较大,动力放大系数高达1.88,在拱梁组合桥设计中应该予以考虑。

The fundamental premise of this research is to study the negative result of half-through arch beams combined system bridges which is produced by one given suspender failure.In this paper,dynamic analysis for suspender fracture of an half-through arch beams combined system bridge is studied by the Vector Form Intrinsic Finite Element(VFIFE)method.Firstly,The failure criterion of prestressed suspender in VFIFE is adjusted.Then a model of steel wire breaking is proposed and validated to investigate the regarding failure.At last,the original VFIFE program is utilized to simulate and analyze the stress redistribution and dynamic response of the structure diferent fracture modes.Thus dynamic response curve of either the stress in suspender or the displacement of beam is obtained.The result of the simulation indicates that VFIFE is accurate in case of analyzing the whole cable rupeure process,and the sudden break of suspender has the greater impact on the adjacent suspenders with a dynamic amplication factorup to 1.88.In conclusion,such sudden break of suspender should be taken into account in design of arch beams combined system bridge.