Study On Vibration System Of Large Concrete Vibrating Table

In recent years,with the development of "building(residential)industrialization",more and more applications of precast concrete have been developed in the field of construction.However,the application of prefabricated parts in China is relatively small,mainly due to the low density of concrete preforms,resulting in poor strength and durability(the main reason lies in the vibration of the concrete vibration frequency in China is low and single).The concrete vibration table is the main equipment for the production of precast concrete,its vibration performance directly determines the preform density level and vibration system(vibration source and vibration form)is the most important vibration component,its performancedirectly affect the vibrationof the processing quality and efficiency.In this paper,the vibration system of concrete shaking table is taken as the research object.Under the premise of analyzing the vibration property,the vibration of the shaking table is improved by using the chaotic exciter with broadband vibration as the output source and the bistatic spring vibration system performance.The specific research contents are as follows:(1)The research status of chaos theory,the mechanism of the vibration compaction of concrete and the related factors of the vibration compaction are introduced.Based on the analysis of several kinds of vibration modes,the vibration mode is determined;(2)On the basis of the brief introduction of the basic concepts of chaotic vibration,the qualitative and quantitative identification methods of chaotic vibration are presented.In this paper,we use the Simulink module in the Matlab to realize the identification of the chaotic vibration and determine there cognition method;(3)The structure of the designed chaotic exciter is simplifiedfirstly,and its mechanical model(three eccentric structure)is obtained.The mathematical model of the exciter is established by mathematical derivation;then the motion of the exciter is simulated by Simulink module in Matlabfollowed by Simulink module in Matlab;finally,the results of simulation analysis are used to identify the eccentric 2 and eccentric 3 vibration characteristics.The results show that eccentric 2 and eccentric 3 are chaotic;(4)Combined three eccentric Chaotic Vibrator with two-body vibrating system,the mathematical model of "chaotic exciter-shaking table" is established.The vibration of the vibration system is simulated by Simulink module in Matlab and the simulation results are analyzed and chaotic.The results show that the maximum vibration acceleration of the vibration table is greater than 10 g,and the vibration of the shaking table is chaotic.The combination of the two can make the concrete aggregate particles move violently,the compact effect is better.Finally,the PFC 2D particle flow analysis software was used to simulate the vibration process of concrete aggregate.The comparison shows that the compactness of the chaotic shaking table is higher than that of the ordinary single vibration table,which provide theory basis for the compaction of concrete in engineering practice.