The Experimental Investigation On Nonlinear Vibration Of Cable-beam Coupling Model

The single-column cable tower and the main column are a typical cable-beam coupling structure.Many scholars have conducted theoretical research on the cable-beam coupling model,but there are few experimental studies.In order to explore the nonlinear characteristics of the cable-beam coupling model,it is of great significance to conduct experimental research on the cable-beam coupling model on the basis of theoretical analysis.This paper studies the static and dynamic characteristics of stay cables,and establishes the free vibration equation of stay cables;Taking the simple coupling structure of single cable-single beam as the research object,use the D’Alembert principle to establish the free vibration partial differential equations of the cable-beam coupling model;Taking into account the effect of the in-plane simple harmonic excitation force on the beam,the forced vibration equation of the cable-beam coupling model is derived,and the internal and external resonance modes of the cable-beam model are discussed using the multi-scale method.The Runge-Kutta method is used to perform numerical calculations on engineering examples and analyze the coupled vibration characteristics of the cable-beam model;Designed a cable-beam coupling experimental model,and gave a detailed introduction to the calculation of model parameters,the choice of experimental instruments and experimental procedures;Experiment to study the nonlinear characteristics of stay cables;The free vibration characteristics of the cable-beam coupling model with a frequency ratio of 1:2 are experimentally studied;the forced vibration experimental study is carried out by adjusting the external excitation frequency,and the forced vibration characteristics of the cable-beam coupling model are discussed.The results show that: The cable-beam coupling model is more sensitive to the initial disturbance of the beam.A slight disturbance to the beam will cause the stayed cable to vibrate greatly,while the initial disturbance of the cable has a limited impact on the beam;When the cable to beam frequency ratio meets 1:2,1:1,2:1,internal resonance will occur,Cable main resonance occurs when the external excitation frequency is equal to the cable frequency,and beam main resonance occurs when the frequency is equal to the beam frequency;Due to the external excitation,the maximum amplitudes of stay cables and beams are both large free vibration amplitudes;the cable’s "jumping" phenomenon is verified in the cable-stayed frequency sweep experiment;The experiment verified that there is a strong mutual coupling and energy conversion between the cable and the beam,which is consistent with the theoretical analysis result;In the case of forced vibration,the cable-beam coupling model and the single-cable model are compared and analyzed,and it is found that the vibration amplitude of the cable-beam coupling model is significantly increased compared with that of the single-cable model;The comparative analysis of the main resonance of the cable and the main resonance of the beam shows that the vibration amplitude of the main resonance of the beam is larger,the time to reach the steady state is longer,and the greater the influence on the stability of the cable-beam coupling model;The frequency sweep experiment analysis of the cable-beam coupling model shows that the cable-beam model will have a "jumping" phenomenon,and due to the parametric resonance and the main resonance,the stay cable amplitude has two peaks.