核环吊地震反应数值模拟分析

Numerical Investigation of the Earthquake Response of Nuclear Polar Crane

将传统反应谱法应用于核环吊抗震分析时,通常需要将轮轨关系绑定,不允许部件相互脱离,因而无法模拟强震作用下可能发生的跳轨行为以及水平轮对安全壳产生的冲击。结合核环吊结构特点,首先,考虑部件间的非光滑接触,采用非光滑多体系统动力学方法建立动力学方程,此模型可以较为真实地反映核环吊各部件间的接触碰撞效应。然后,利用模型降噪方法滤除系统中过高频率的弹性振荡,使用这种方法修正的多柔体系统动力学方程求解兼具简便性与快速性。随后,将轮轨间接触力简化为接触点的法向接触力和摩擦力,采用库伦干摩擦模型描述其摩擦力,提出一种光滑化线性互补模型计算轮轨间动态接触力,该模型可综合考虑接触和碰撞,不必在接触状态发生改变时切换模型。同时,根据处理静摩擦开关效应的相关理论,对水平隔震装置阻抗性能曲线进行处理,克服其难以用于数值计算的困难。最后,通过数值模拟侦测到了强震作用下核环吊结构的跳轨现象,该仿真模拟算法与平台可为三代核环吊的设计提供数据参考。

Derail phenomenon and impact events between horizontal wheels and circular track are the most important issues for contact analysis under strong earthquake.Traditional response spectrum method requires the wheel-rail to be bundled,therefore different structure parts cannot be separated from each other,thus the mentioned phenomenon are difficult to be simulated.First,the kinetic equations are set based on the non-smooth dynamic methods reflecting the contact/impact effect between different structure parts of the nuclear polar crane.Second,model smoothing method is used to filter out the high frequency elastic component,which makes the simulation of the system equations have both simplicity and convenience.Then,the contact force between wheel and rail is simplified as normal forces and frictional forces of contact points.Moreover,modified Coulomb’s law for dry friction is employed to describe frictional forces.A smoothing linear complementarity formula is raised to calculate the dynamic contact forces between flexible bodies,the presented method can comprehensive consider the smooth contact and impact without changing contact force model when the contact status change.Meanwhile,the discontinuity of the resistance force is smoothed according to the method of dealing with the switching effects in the Coulomb’s law,hence the numerical difficulties have been overcome.Finally,numerical results detect the derail phenomenon under strong earthquake.These results prove the feasibility and possibility of this algorism and program being used for guiding development of the design process of the nuclear polar crane.