Test And Analysis Of The Dynamic Characteristics Of The Derrick Beam Floor Under Vibration Excitation

With the rapid development of society and the continuous improvement of science and technology,people have higher and higher requirements on the quality of industrial production.In recent years,due to limited space in industrial plants,more and more large machinery production equipment has been forced to work on higher floors,the vibration produced during the operation of the equipment will not only affect its normal operation,but also cause obvious discomfort to the staff,once the excitation force frequency generated during the operation of the equipment is close to the natural vibration frequency of the floor,the floor will produce a strong vibration,serious resonance phenomenon will occur,resulting in structural damage and major safety accidents.In this paper,the obvious vibration of floor near a factory building on the sixth floor of a company is taken as the research background,and the floor vibration characteristics are analyzed by two methods: field dynamic characteristic test and finite element simulation,to provide certain reference for the subsequent vibration reduction and isolation design.The main research contents are as follows:1.By testing the field dynamic characteristics of the derrick beam floor of a certain company,the natural vibration frequency of the floor and the time-history curve of acceleration at different locations near the normal operation of the equipment are obtained.According to the test results of field dynamic characteristics and the relevant regulations on allowable values of vibration and comfort of human body,it is preliminarily determined that the main reason for floor abnormal vibration is insufficient floor stiffness.2.Conduct the modal analysis and harmonious response analysis by the finite element method,and obtain the natural vibration frequency and modal vibration characteristics of the derrick beam floor.The calculated and measured values of the natural vibration frequency and dynamic response of the floor are the same,indicating the reliability of the finite element model.3.The dynamic load is simulated in the way of excitation wave and applied as excitation source to the calculation model for dynamic time-history analysis.By comparing the test results of dynamic response with the results of finite element calculation,it is found that the vertical excitation force is the main reason for the vertical vibration anomaly of the floor of the derrick beam when the equipment is working,and the main reason for the abnormal vibration of the floor of the derrick beam is that its own stiffness is insufficient,and the floor of the derrick beam has resonance phenomenon when the equipment is working.