简谐激励作用下轴向运动梁横向振动特性分析

为分析简谐激励作用下轴向运动梁的横向振动问题,采用单元数目及长度固定不变、节点参数在不同时间步下无缝传递的节点生死方法,建立了时变系统的动力学有限元模型,通过已有实例验证了模型的准确性和有效性。在此基础上,分析了架设速度、激励力频率和幅值对某型平推式军用桥梁架设过程横向动力响应的影响规律。结果表明,在架设过程中,当桥梁的时变固有频率与激励力频率接近时,桥梁位移动态响应呈共振的特点,据此提出了减小某型平推式军用桥梁架设过程动力响应的措施。

Lateral vibration characteristics analysis of an axially moving beam subjected to harmonic excitation

In order to analyze transverse vibration of an axially moving beam under harmonic excitation,a dynamic finite element model of the time-varying system was established by using node's birth and death method which made element number and length fixed and the parameters of nodes under the condition of different time steps transferred with less error.The accuracy and validity of the model were verified by an existed example.Subsequently,the influence of erection speed,excitation frequency and amplitude on lateral dynamic response of a certain type of military bridge erected horizontally was analyzed by an example during erection process.The results show that the displacement response of the bridge presented with resonance when time-varying natural frequency closed to the frequency of excitation force in the erection.Some measures were proposed for reducing dynamic response during erection process of military bridge based on the calculations.