基于隐式动力学的起重机轮—轨摩擦系统振动分析

Implicit Dynamics Analysis on the Vibration Characteristics of Crane Wheel-Rail Friction System

本研究建立起门式起重机车轮—轨道耦合动力学模型,基于ABAQUS/Implicit隐式动力学分析算法,探讨起重机轮—轨摩擦系统的振动特性。结果表明,系统低频模态表现为起重机主梁/轨道的弯曲变形,中频模态表现为起重机主梁/轨道的弯曲加扭转变形,而高频模态表现为主梁—轨道—车轮三者的耦合运动。在车轮与轨道摩擦过程中,车轮侧向产生持续的摩擦自激振动,轮—轨之间可能产生"啃轨"现象。相比之下,车轮的切向振动和法向振动强度相对较弱,主要产生在车轮运动的初始阶段,且切向振动强度明显大于法向振动,这可能导致所提升物体的切向偏摆更加剧烈。频域分析结果表明,车轮与轨道均能产生频率约为566 Hz的振动,起重机轮—轨之间的摩擦振动具有多频复合特征,是一种部件耦合与独立振动并存的非线性动力学行为。进一步地,本研究对车轮载荷不对称状态下的系统动力学响应进行分析,结果表明车轮载重较大一侧的侧向振动增强,而车轮载重较小一侧的切向振动和法向振动在初始阶段波动更为剧烈。由于载重不同,两侧轨道接触应力变化差异明显,载重更小的一侧可能出现短暂的轮轨分离与重新接触现象,这导致起重机轮轨系统的最大应力位置随着时间不断发生变化,导致运输不稳定的现象严重并带来严重的安全隐患。本研究结果对认识起重机的稳定性具有一定的意义,并能为改善起重机摩擦振动问题的结构设计提供参考。

In this study,the wheel-rail coupling dynamic model of gantry crane is established. The friction vibration characteristics of the crane wheel-rail system are discussed by using ABAQUS/Implicit dynamic analysis algorithm. Results show that the low-frequency mode is the bending deformation of the crane girder/track,the middle-frequency mode is the bending and torsional deformation of the crane girder/track,and the high-frequency mode is the coupling motion among the girder,track and wheel. During the friction process,the lateral of the wheel produces continuous self-excited vibration behavior,and thus may cause the phenomenon of‘gnawing the rail’between wheel-rail. In contrast,the intensity of tangential and normal vibration of the wheel is relatively weak,mainly occurring in the initial stage of the wheel movement,and the intensity of tangential vibration is significantly greater than that of normal vibration,which may lead to more violent phenomenon of tangential deflection of the promoted object. The results of frequency domain analysis show that both wheel and track can produce vibration with a frequency of about 566 Hz,and the friction vibration between wheel and rail of the crane has multi-frequency composite characteristics,which is a nonlinear dynamic vibration behavior of coupling and independent vibration. Further,this study analyzed the dynamic response of the system under the asymmetrical load of the wheel,and the results shows that the lateral vibration of the side with large wheel load is enhanced,while the tangential and normal vibration of the side with small wheel load fluctuate more violently in the initial stage. Due to the different load,the contact stresses of the left and right rails are visibly different,the side with smaller load may have transient wheel-rail separation and re-contact,which causes the maximum stress position of the wheel and rail system of the crane to change with time,resulting in serious transport instability in the process of lifting transportation. The results of this study have a certain meaning to understand the stability of the crane,and can provide a reference for improving the structure design of the crane’s friction vibration problem.