Dynamic Modeling And Simulation Of Flexible Beam Multibody System Based On The Nodal Coordinate Based Floating Frame Of Reference Formulation

In the dynamics of flexible multibody systems,the traditional floating frame of reference formulation usually uses linear finite element method or assumed modal method to discretize the flexible body,so the large deformation of the flexible body cannot be accurately described.Based on the traditional floating frame of reference formulation,this dissertation uses absolute nodal coordinate elements to discrete the flexible body to study large deformation problems of the flexible beam multibody system.The rigid-flexible coupling modeling theory of hub-flexible beam system that performs a large-scale rotation in the plane is studied,and the rigid-flexible coupling dynamic equation of the system is derived based on the nodal coordinate based floating frame of reference(NCFFR)formulation.This method has the advantages of both floating frame of reference formulation and absolute nodal coordinate formulation.It can separate large-scale rigid body motion of the system and elastic deformation motion of the flexible body,and can accurately describe the coupling interaction between large rotation and large deformation.Through two simulation examples,the difference between this method and absolute node coordinate formulation and high-order coupling model is compared,and the correctness of this method in dealing with large deformation problems is verified.The nodal coordinate based floating frame of reference formulation is extended to the modeling theory of chain flexible manipulator arms system.The flexible joint is simplified to a linear torsion spring-damping model and its quality is considered.D-H method is used to establish floating frame of reference on each flexible link.Absolute nodal coordinate element in the floating frame of reference describes the elastic deformation of each flexible link,and uses the recursive lagrangian method to derive the rigid-flexible coupling dynamic equations of chain flexible manipulator arms system.During the entire modeling process no small deformation assumptions are used.On this basis,a general-purpose chain flexible manipulator arms system dynamics simulation software was written,and the correctness of the dynamics model was verified through simulation examples.