Study On Ageing Resistance Performance Of Damping Materials And Constrained Damping Constrained Damping Structure

Effect of viscoelastic damping material and constrained damping structure will be subject to various aging conditions,and this will reduce the damping effect,seriously affect the quality of the project.So I hope that we can do the aging experiments,get the aging rules in order to take appropriate methods to reduce the overall performance decline of the material and constrained damping structure.So that the material and constrained damping structure can have a better damping performance.This article choose Qtech T501-I viscoelastic damping material and constrained damping structure with this material as the research object,mainly used four aging conditions,including high and low temperature cycles,freeze-thaw cycles,saturatedCa?OH?₂ solution immersion and salt spray environment to aging the material and structure,studied the mechanical properties and microstructure changes of this viscoelastic damping material.The microscopic changes between the coating and mortar substrate interface were discussed by using the method of pasting strain gauges on the mortar substrate,and this article also discussed the effects of environmental temperature,bending load saturated Ca?OH?₂ solution coupling and bending load salt fog environment coupling on the stress,strain,gloss,adhesion and strength of the interface of the coated mortar specimen.Four different aging conditions effect of constrained damping structure changes showed that the damping properties of constrained damping structure by the material produced decreased slightly after aging,but still can guarantee a good damping performance.The conclusions were as follows.1.Before and after aging text of the mechanical properties and FTIR analysis of samples showed that the tensile strength of Qtech T501-I is 1.31MPa,the breaking elongation rate was 939.99%,the tear strength is 5.58N/mm,the shore A hardness of the average value is 18,the average gelation time is about 258s.The average dry time is about 56min,the solid content reached 92.29%,and after the surface treatment there was no crack after a low temperature bending test.After 120d aging in the four aging conditions,the results showed that the mechanical properties were decreased in varying degrees,after the saturated Ca?OH?₂ solution the mechanical properties were decreased significantly which the tensile strength decreased by 47.33%,the effect of salt spray aging was little less which the tensile strength decreased by 45.04%,the effects of high and low temperature cycles and freeze-thaw cycles on the mechanical properties of the materials are small.The FTIR analysis results showed that before and after aging the individual represents some groups and peak amplitude decreased,indicated that after aging the material chemical bond between molecules was damaged to a certain extent,but still retained its basic performance the unchanged,indicated there was still retain good damping performance.2.The experiment of static stress and strain at the interface between the coating and the substrate,bending load saturated Ca?OH?₂ solution coupling and bending load salt fog environment coupling showed the interface had no obvious strain at normal temperature,which was in a steady state.After 8 hours of testing at 60 degrees Celsius,the strain of mortar was found to rise first and then flatten,and its maximum value was about 45.After 8 hours of testing at-30 degrees Celsius,the strain of mortar was found to decline first and then flatten,and its maximum value was about-60,showed that low temperature has more influence on the material properties and its bonding with the substrate,which consistent with the macroscopic material under low temperature and reduced adhesion.The experimental results of mortar gloss,flexural strength and adhesion of the coating showed that the coating block has a protective effect on mortar,and bending load saturated Ca?OH?₂ solution coupling has the greastest effect on mortar impact,after this aging test block gloss decreased by 54.78%,the flexural strength decreased by 13.75%,coating adhesion decreased 22.01%.After aging by bending load saturated Ca?OH?₂ solution coupling and bending load salt fog environment coupling,the strain value at the interface showed a certain fluctuation which has a trend of overall decline after has a slight upward,but the material can still maintain good bonding with the substrate,which can ensure its damping effect.3.The damping properties of constrained damping structures before and after aging showed that the initial loss factor of the constrained damping structure were 0.2125,0.2164,0.2143 and 0.2215,after 90d of the four aging conditions the loss factor decreased by 3.81%,4.07%,4.48%and 4.02%,indicating that the structure have different degrees of aging,the saturated Ca?OH?₂ solution conditions have significant influences on the damping properties of the structure.Therefore,it is necessary to pay special attention to the influence of alkaline environment on the damping performance of the structure.The experimental results showed that the experiment of constrained damping structure vibration acceleration level of the total initial values were 134.43dB,133.25dB,132.56dB and 133.85dB,after 90d aging of the four conditions the total vibration acceleration level were increased by 1.82%,2.33%,3.24%and 2.87%,indicated that the saturation Ca?OH?₂ solution had the greatest influence on the damping properties of the structure.After aging the vibration acceleration level values of structure were increased within the scope of 0-1000Hz,showed that the damping properties decreased slightly.But the vibration acceleration level values almost unchanged in the range of 0-200Hz,indicating that after aging the structure damping effect was slightly reduced,but it can still maintain good damping performance.