Experimental Study And Finite Element Analysis On Vibration Control Of Structures With Viscoelastic Damping Layer

Viscoelastic damping material has been widely used in the fields of aerospace,aviation, machinery and military as a kind of advanced damping material for thestructural vibration attenuation. In this study, free and constrained viscoelasticdamping materials are employed to control the vibration of low frequency structuralmembers experimentally and numerically. The main contents of the thesis are shownas follows,(1)The introduction to the basic characteristics and the constitutive model ofviscoelastic damping material, the corresponding performance indices, the effect ofthe parameters on the damping performance of the viscoelastic material is made,moreover, several available finite element algorithms for the analysis of theviscoelastic damping material and the methods for the determination of dampingproperties of viscoelastic damping materials were introduced in this thesis. The shearstorage modulus (G’) and the shear loss modulus (G’’) of the viscoelastic dampingmaterial employed in this study against frequency at various temperatures weremeasured by means of the vibration beam testing method.(2)Experimental study on the structures with constrained viscoelastic dampinglayer was carried out. The dynamic mechanical properties of partially bondedviscoelastic damping layer on the dynamic characteristics of steel and aluminumcantilever beams were analyzed. Based on the orthogonal test table, the effects of thewidth and the position of the viscoelastic constrained damping layers on the vibrationcontrol were investigated by using the analysis of variance approach.(3)Modal tests on the vibration control of flexible structures with constrainedviscoelastic damping layer and free viscoelastic damping layer were carried outrespectively to discuss the energy dissipation capacity of the these two kinds ofmaterials for both flexible metal plates and two frame structures.(4)Numerical analysis on the dynamic mechanical properties of test specimensbonded with constrained viscoelastic damping layer with the complex eigenvalueanalysis method in ANSYS was carried out. The natural frequencies and dampingratios of the composite structures were calculated. The results obtained from thepresent finite element approach were close to the results from experiments. Based onthe dynamic analysis of the cantilever beam models which were partially bonded with viscoelastic constrained damping layer, the analysis of the parameters of theconstrained damping layer on the vibration of the specimens including the shearmodulus and the damping ratio of the viscoealstic damping materials was conducted.Results show that the damping ratio of the composite structures increases linearlywhile the damping ratio of the viscoelastic damping layer is increased. Moreover, itcan be found that the energy dissipation capacity of the viscoelastic constrained layerdamping is better than that of the viscoelastic free layer damping. The damping ratioof the composite structures firstly increases up to a peak value with the increase ofGr/Es, and then decreases gradually.