Research On The Properties Of Viscous Damping Materials And Its Damper

Viscous fluid damper is a kind of energy-dissipation device, which is important andhas good properties. It can effectively reduce the vibration response of structure underearthquake and wind excitation, and ensure the safety and stability of structure. Theenergy dissipation of viscous fluid damper depends mainly on internal friction ofdamping medium. The properties of damping medium have a great influence on thedamper’s energy dissipation capacity. Currently domestic studies on damping mediumare still very few. In combination with the request of viscous fluid damper, we need todevelop a new type of viscous damping material.At first, this paper put forward the principle and method for synthesis of newmaterials, and prepared a series of viscous damping materials; Secondly, itcharacterized the basic properties of materials, and respectively studied viscosity,viscosity-temperature property, shear properties and dynamic mechanical properties;Thirdly, it studied and evaluated the practical application effect of new materials bytesting the dynamic properties of viscous fluid damper; Lastly, it processed theanalysis research on the thermal stability by Infrared Spectrum. The main researchconclusions are as follows:(1) Preparing viscous damping samples D1～D5with different mass fraction of hardsegment, and the mass fraction of hard segment were26.2%、32.5%、36.6%、42.3%、50.2%. Viscosity is the most important performance characterization of viscousdamping materials. Viscosity test found that the mass fraction of hard segment washigher; the viscosity of the sample was greater. The influence of temperature on theviscosity showed that: when the temperature rose to90℃from10℃, the decreaserate of viscosity was92%,93%,93%,90%,93%. In addition, theviscosity-temperature coefficient can also express viscosity-temperature characteristicof viscous damping materials. D1～D5viscosity-temperature coefficient were0.58,0.59,0.57,0.48,0.43. The higher hard segment was, the smaller viscosity-temperaturecoefficient was and viscosity changed with temperature. The constitutive relation isk n, which is determined by the shear rate and shear stress. The hard segment of D5was the largest; its k value was maximum, so its viscosity was greater; the nvalues of D1, D3and D5were less than1, belonging to shear thinning fluid. The nvalue of D5was maximum, so its shear thinning phenomenon was not obvious.(2) Frequency, temperature and mass fraction of hard segment have influence on thedynamic performance of viscous damping material. When frequency increased,energy storage modulus and loss modulus increased, and complex viscosity reduced,and loss factor increased first and reduced afterwards. When temperature rose, storagemodulus, loss modulus and complex viscosity reduced, and loss factor decreased firstand increased afterwards. Mass fraction of hard segment increased, storage modulus,loss modulus and complex viscosity increased, but loss factors reduced.(3) Viscous damping material is a kind of polymer. The temperature has a greataffect on its chemical performance. After thermal weight loss experiment, D1～D5viscous damping materials were oxidized and weightless. And the higher hardsegment fraction was, the smaller weightlessness rate was. The infrared spectrumanalysis found that the hard segment fraction increased, hydrogen bonding groupsalso increased; After thermal aging experiment for48hours, the hydrogen bondstructure was further increased, the molecular structure combined more closely andviscosity increased.(4) The dynamic performance of viscous fluid damper can fairly reflect the energydissipation of viscous damping materials. Viscous fluid dampers with double guidebars were made by D1, D3and D5damping medium. It studied that excitationfrequency, displacement and viscosity of damping medium had an influence on thedynamic performance of dampers. In vibration, the damper can form ovalforce-displacement hysteretic curves. In the condition that the excitation frequencyincreased, and the displacement increased, and the viscosity of damping mediumbecame higher, the energy dissipation raised. Viscous fluid damper is a kind ofvelocity-related damper. The relationship between damping force and speed isF C.Regression analysis showed that damping coefficient C of D5wasmaximum and speed index was minimum. It proved that the energy dissipation capacity and nonlinear of D5were higher than others. So D5damper was moresuitable for engineering application.According to comprehensive analysis on the above research conclusion, there are stillinsufficient in research methods and performance of the new viscous dampingmaterial. But it provides data support and research direction for the modification ofviscous damping materials and the optimization design of dampers.