超长柔吊装臂架回转作业刚柔耦合动力学模型与分析

Rigid-flexible dynamic modeling and analysis of super long and flexible boom system in case of slewing motion

针对超长柔臂架系统在回转吊装运动中的非线性动力学行为,开展了模型构建与振动特性分析。考虑大型起重机臂架的刚柔耦合运动特征与吊装大挠度效应,利用混合坐标系描述了吊臂刚柔耦合运动,在臂头随动坐标系上描述吊重与钢丝绳的偏摆运动;通过初应力法构建了结构的几何非线性刚度矩阵;采用拉格朗日方程,推导并给出了综合考虑超长柔臂架刚柔耦合效应、几何非线性效应、惯性力效应的动力学分析模型。通过对某轮式起重机的动力仿真分析,结果表明:超长柔臂架在吊臂几何非线性效应影响下,吊重偏摆幅度增大,周期延长;吊载愈重,几何非线性效应对吊臂振动及吊重摆动的影响愈明显;轻载吊装吊臂振动主要由回转惯性力引起,但重载时吊臂振动规律取决于吊重偏摆振动。分析结果为臂架结构设计及控制系统设计提供了依据。

A rigid-flexible dynamic model for the flexible boom system of the truck crane is developed,and the nonlinear dynamic characteristics are analyzed.Considering the rigid-flexible dynamics and large deflection in hoisting for the super long and flexible boom structure in case of slewing motion,a hybrid coordinate model is introduced to describe the wide range rotary motion and elastic vibration of the boom,in which a floating coordinate system connect to the tip of the boom is used to describe yaw motion for the rope,and the geometric nonlinear stiffness matrix is constructed with the initial stress method.The dynamic model is developed based on the Lagrange equations,with the effects of the rigid-flexible coupling,inertial force and geometric non-linear on the boom systems are taken into account.The validity of dynamical model is verified by the simulation of a practical truck crane.Results obtained show that,the amplitude and the period of yaw angle increases,under the influence of the large deflection effect of the boom,moreover,the influence will be increased if the load grows,the vibration law for the boom depends on the inertial force in the condition of light loads,however these law will be decided by the yaw motion of the load with the increasing of the load weight.The analysis results may provide a basis for the design of the boom system and the control systems.