Research On Vibration Reduction Scheme Of Well-shaped Beam Floor Under Simple Harmonic Loads

The vibration caused by the operation of the equipment in the industrial plant is often unavoidable.We need to take measures to reduce the vibration isolation to control the vibration amplitude in a reasonable range.In this paper,the dynamic characteristics of the cross beam slab in an industrial workshop were tested in the field.Based on the test results,a local cross beam slab model was established by using the finite element software ABAQUS to study the vibration characteristics of the cross beam slab under harmonic load,and a vibration control scheme of increasing the floor stiffness,laying out vibration isolators and adding TMD was proposed.As a kind of long-span system,the cross beam slab is very practical for building structures with large space requirements.However,the vibration control of the cross beam slab under harmonic load has not been reported.Through the research in this paper,it provides some reference for the vibration control of the cross beam slab under the action of harmonic load.This thesis mainly studies the following aspects:(1)The "plate-column" model of the local cross beam slab was established by ABAQUS finite element software.The difference between the vertical first-order natural vibration frequency and the measured value was within 5% after modal analysis of the structure,which verified the rationality of the model.Based on the transient analysis of the structure,the calculation results show that the peak acceleration of vertical vibration of the floor in a certain range from the east side,south side and north side of the equipment does not meet the requirements of the code,so it is necessary to reduce the vibration and strengthen the cross beam slab.(2)The vibration control of the cross beam slab was studied by increasing the floor stiffness method,and three vibration reduction schemes for increasing the floor stiffness were proposed,namely,increasing the beam height or the floor thickness and adding the secondary beam.Based on the original model,the finite element models were established for different vibration reduction schemes.The calculation results show that the peak acceleration of vertical vibration of floor decreases by increasing beam height,plate thickness and adding secondary beams.In the scheme of increasing beam height,the effect of increasing the height of primary and secondary beams is obvious.In the new secondary beam scheme,the secondary beam is arranged at the equipment support to reduce the vibration effect is better.Among the different vibration reduction schemes,the one of increasing the height of the primary and secondary beams is the best one,followed by the one of increasing the height of the secondary beams.(3)The vibration control of the cross beam slab was studied by adding TMD,and the finite element model was established by hanging the TMD under the cross beam slab.The calculation results show that the vibration reduction effect of four TMD with a mass ratio of 2% is better than other arrangement methods when the floor of the cross beam slab studied in this thesis is placed under the beam near the equipment support.(4)The vibration control of the floor of the cross beam slab was studied through the arrangement of vibration isolators.The six supports of the equipment were connected with the cross beam slab through the arrangement of vibration isolators to establish a finite element model.The calculation results show that the peak acceleration of vertical vibration decreases obviously after the placement of vibration isolator,and the peak acceleration of vertical vibration at each pick point meets the limit of the code,and the vibration reduction rate of each pick point reaches about 80%.