悬索桥吊索断裂动力响应分析的有限元模拟方法研究

Research on Simulation Method of Dynamic Response Analysis for Suspension Bridges Subjected to Hanger-breakage Events

为精确模拟吊索断裂动力过程,基于拆除构件法,对模拟悬索桥断索动力过程的数值方法展开研究.以某自锚式悬索桥为工程背景,详述了三种悬索桥吊索断裂动力过程模拟方法(瞬时刚度退化法、瞬时加载法、等效卸载法)的机理和特点,并对影响结构断索动力响应的因素展开分析.研究表明:采用瞬时刚度退化法模拟悬索桥吊索断裂动力过程简单有效;悬索桥断索后结构的动力响应与限元分析模型中是否包含失效吊索单元、断索持续时间、断索过程中吊索拉力损失变化关系以及断索工况等因素密切相关.

In order to accurately simulate the dynamic process of the cable rupture event,based on the alternate load path(ALP)method,the numerical simulation methods for dynamic analysis of suspension bridges subjected to hanger-breakage event are studied.Taking a prototype self-anchored suspension bridge as the background,the basic principles and characteristics of three methods(e.g.,the instantaneous stiffness degradation method,the instantaneous loading method and the equivalent unloading method)are illustrated.In addition,the influencing factors on structural dynamic effect of the collapse responses are quantitatively analyzed.The results indicate that the instantaneous stiffness degradation method is simple and effective to simulate the dynamic process of the hanger-breakage event.The hanger loss induced dynamic responses are closely associated with the influencing factors,such as the broken hanger elements in the finite element model,the duration and time-dependent tension loss function of the breakage process,and hanger loss scenarios.