The viscoelastic materials generally used are copolymers or glassy substances. Study on mechanical properties of high damping viscoelastic dampers. The fractional zener model is used to describe properties of the viscoelastic body while the friction damper is modelled by the coulomb friction law in a setvalued form. It is concluded that connecting the two adjacent baseisolated buildings with the viscoelastic dampers is useful in controlling large bearing displacements in the base. The damper properties are designed with reference from literature papers by m. Dynamic responses of coretubes with semiflexible suspension. In this paper, tests on viscoelastic ve dampers are carried out, and the results indicate that ve dampers have high energy dissipation capacity and excellent antifatigue properties. The temperature scanning tests were carried out by a rheogele4000dma analyzer and the results showed the modulus and loss factor of viscoelastic damping material. Structural dampers viscoelasticity mechanical engineering.
A design method of viscoelastic damper parameters based on the. We use your linkedin profile and activity data to personalize ads and to show you more relevant ads. In past relevant research, most analytical models for characterizing the mechanical behavior of ve dampers were. Reducing vibrations with viscoelastic structural dampers.
This application studies a forced response of a typical viscoelastic damper. When viscoelastic dampers are used, the force f i t at a generic instant t 0 depends in principle on the whole time history of the associated deformation d i s l i y s, with 0. Review on viscoelastic materials used in viscoelastic dampers. A sequential procedure is developed for optimally placing ve dampers to structures, based on the concept of degree of controllability. An alternative practical design method for structures with. Viscoelastic damper has been long used in vibration control of structures. Fluid viscous damper that operates according to the. To examine the response reducing effectiveness of these dampers, it is necessary that engineers are able to conduct response analysis of structures installed with added dampers accurately and efficiently. The elastomeric pads in damper a contained a single rubber layer with no internal reinforcement fig. Life cycle testing of viscoelastic material for hubble. This structure is composed of the primary coretube, suspended segments regarded as suspension systems, viscoelastic dampers and flexible layers. Frontiers properties tests and mathematical modeling of. These tuned mass dampers are in general less costly than the more.
In the last decades viscoelastic dampers have been successfully used with the aim of mitigating the structural vibrations induced by natural actions, such as seismic motions, wind gusts, or ocean waves. With the goal of developing impactful infrastructures and buildings that meet safety requirements for withstanding lowfrequency vibrations, viscoelastic structural dampers are a valuable resource to designers. This damper represented a benchmark damper as its configuration was similar to the conventional viscoelastic dampers. The configuration, simplified model and the formulation of the multidegrees of freedom equations of motion for this structure are given. Optimal seismic retrofit of fractional viscoelastic.
Viscoelastic damper connected to adjacent structures. Modeling of a viscoelastic damper and its application in structural control. The properties of ve dampers are briefly described. Some practical issues associated with the application of viscoelastic ve dampers to building structures for seismic performance enhancement are studied in this paper. The system is assumed to be elastic and responses of the system are obtained in frequency domain for stationary random seismic excitations. Viscoelastic ve dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating windinduced vibration. Oct, 2018 viscoelastic ve dampers, with their stiffness and energy dissipation capabilities, have been widely used in civil engineering for mitigating windinduced vibration and seismic responses of structures, thus enhancing the comfort of residents and serviceability of equipment inside.
Numerical examples on two common viscoelastic dampers demonstrate the advantages of the smm over fractional derivative and powerlaw models. Jul 11, 2018 viscoelastic dampers veds are one of the most common passive control devices used in new and retrofit building projects which reduce the structure responses and dissipate seismic energy during an earthquake. Viscoelastic damper is a kind of commonly used passive control device for. Dampers are components that counteract and often isolate the vibration source from the rest of the design or machine to prevent damage. This paper addresses the mathematical modelling of ve dampers and the dynamic analysis of structures with ve damp. The viscoelastic solid materials are used as a means to dissipate energy in viscoelastic dampers. Mahmoodi, design and analysis of viscoelastic vibration dampers for structures, in proc. Model, tests and application design for viscoelastic dampers. Some examples of these phenomena are discussed in this section1. Energy dissipation dampers viscoelasticity friction. Design and implementation of tuned viscoelastic dampers. The model parameters have physical meaning and they can be determined from simple timedomain and. Use of viscoelastic dampers in reducing wind and earthquake. The typical viscoelastic damper consists of viscoelastic layers bonded with steel plates or solid thermoplastic rubber sheets sandwicthed between steel plates.
Behavior of ve rubber dampers is a rate dependent phenomenon 3 8. Parameters of viscoelastic dampers can be obtained directly using the proposed method. The sevenparameter fractional derivative model is modified with the temperaturefrequency equivalent principle and utilized to describe the dynamic properties. Viscous fluid dampers vfds and viscoelastic ve solid dampers belong to rate dependent passive dampers. A procedure for evaluating the ve damping effect when added to a structure is proposed in which the damping effect of ve dampers is incorporated into modal damping. The mechanical properties of the viscoelastic damper made of high. The damper can easily be manufactured and installed in a short time.
Viscoelastic ve dampers have been successfully incorporated in a number of tall buildings as a viable energy dissipating system to suppress wind and. Dampers a, b, and d contained two elastomeric pads of 200 by 200 mm plan dimensions. Analyze the design of a viscoelastic structural damper. Francis shangrila place, mandaluyong city, philippines. Regarding the experiment, we report the results of an evaluation of seismic resistance against input in an. Through the procedure, the dampers are placed one by one in stories with maximum interstory drift at each sequence. Performance based placement of viscoelastic dampers in an r. Due to a horizontal ground excitation the viscoelastic plate is exposed to a shear loading. Before these devices can be incorporated into a structures design, there is, of. A viscoelastic damper particularly suited for use in a rotor system of a helicopter or the like is provided to damp leadlag motion of the blade relative to the rotor hub. The dynamic responses of structures with and without dampers are compared. The common feature is that the frequency of the forced vibrations is low. Chang 5 viscoelastic materials are highly influenced by parameters like temperature. Pdf viscoelastic damper connected to adjacent structures.
In the present paper, several dynamic properties tests of the viscoelastic damper at. Viscoelastic ve dampers are one of the most common earthquake mitigation devices. These tuned mass dampers are in general less costly than the more commonly used tmds employing viscous. Viscoelastic structural damper comsol multiphysics. Viscoelastic structural dampers have been implemented into structural layouts as a means to limit the strain and decrease the risk of failure in building components due to. Passive means of vibration attenuation have been employed successfully and efficiently in machining systems such as turning and milling.
Model, tests and application design for viscoelastic dampers zhao. Also viscoelastic dampers are often used in base isolation systems, see e. Viscoelastic damper connected to adjacent structures involving seismic isolation. An elongate body of viscoelastic material has an inner plate embedded centrally therein and extending longitudinally thereof. In recent years, viscoelastic dampers veds have been widely used in many mid and highrise buildings. Author links open overlay panel amir rashid a cornel mihai nicolescu b. Damping, as a method to reduce unwanted vibrations, is most effective in cases where the vibratory system is excited with a frequency close to its natural frequency. Modeling of viscoelastic dampers for structural applications. Viscoelastic dampers as energy dissipation devices for. Numerical results demonstrating the response reducing effect of viscoelastic dampers are also presented. Viscoelastic coupling dampers vcds for enhanced wind and. The present paper concerns the development of a new rather inexpensive friction viscoelastic damper and its application in a damping system for base isolation of a structure. In recent years, numerical tools such as finite element method have been utilized to optimize the structure of ve rubber damper devices 9, 10. Jun 01, 2017 modeling of a viscoelastic damper and its application in structural control.
Read our latest whitepapers to learn more about the industry and latest innovations from sorbothane. Separate elongate nonextensible outer plates are secured to opposite sides of the body in spaced. Use of viscoelastic dampers in reducing wind and earthquakeinduced motion of building structures. Seismic analysis of structures with a fractional derivative model of. On the basis of extensive analytical and experimental investigations, some practical issues associated with the application of viscoelastic dampers to building structures for seismic performance en. Viscoelastic dampers veds are one of the most common passive control devices used in new and retrofit building projects which reduce the structure responses and dissipate seismic energy during an earthquake.
Viscoelastic dampers veds are one of the most common passive control devices used in new and. During the march 2002 servicing mission by space shuttle sts 109, the hubble space telescope hst was refurbished with two new solar arrays that now provide all of its power. Correlation coefficients for structures with viscoelastic dampers. These arrays were built with viscoelastic titanium dampers, integral to the supporting masts, which reduce the interaction of the wing bending modes with the telescope. Vibration damping and isolating in engineered designs. Modeling of a viscoelastic damper and its application in structural. Pdf design and implementation of tuned viscoelastic. Equivalent fractional kelvin model and experimental study on. Influence of damping systems on building structures subject to seismic effects proceedings of the ninth international conference on civil and structural engineering computing, egmondaanzee, the netherlands, september 2003. Previous studies have shown that fractional derivative models present a plausible level of accuracy when it comes to capturing the behavior of viscoelastic dampers due to being capable of expressing the effects of excitation frequency and ambient temperature in viscoelastic damper parameters. This paper addresses the mathematical modelling of ve dampers and the dynamic analysis of. Various methods to design this kind of dampers have been proposed based on the desired level of additional damping, eigenvalue assignment, modal strain energy, linear quadratic. Seismic design of viscoelastic dampers for structural. The purpose of the app is to compute and analyze the important parameters of the damper such as the hysteresis loop and.
Considering the possibility of earthquake occurrence during a structure lifetime. Various methods to design this kind of dampers have been proposed based on the desired level of additional damping, eigenvalue assignment, modal strain energy, linear quadratic regulator. In the design of many structures, a particular area of concern is exposure to seismic and windinduced vibrations. Fluid viscous damper is composed of a piston head, a piston rod and a cylinder full of a viscous fluid. Pdf evolutionary model of viscoelastic dampers for. The model parameters have physical meaning and they can be determined from simple timedomain and frequencydomain tests. Viscoelastic damper, metallic damper, tuned mass damper and friction damper etc. This paper investigate the performance viscoelastic dampers under explosive loading, through presenting the. Experimental and analytical study on design performance of. Published experimental data from a viscoelastic liquid. Pdf performance of viscoelastic dampers under explosive. Considering the possibility of earthquake occurrence during a structure lifetime, minimizing the life. The solid viscoelastic dampers are among such passive energy dissipation systems.
Pdf viscoelastic dampers utilize high damping from viscoelastic materials to dissipate energy through shear deformation. A feasibility study on precompressed partially bonded. Vicodas viscoelastic dampers are designed in a way that they can be used in a wide. Article information, pdf download for model, tests and application. The viscoelastic dampers and damping parameters are tested and monitored by our inhouse test lab and independent test laboratories based on safety standard kta 3205. Correlation coefficients for structures with viscoelastic.
Damping elements involving layers of viscoelastic materials are often used for reduction of seismic and wind induced vibrations in buildings and other tall structures. This paper presents an analytical model for predicting the hysteretic behavior of viscoelastic dampers based on the boltzmanns superposition principle and the method of reduced variables. A material selected to exist in this region is ideally suited for such devices as isolators or tuned mass dampers because the modulus varies only slightly with changes in temperature and frequency. Analytical modeling of viscoelastic dampers for structural. The present paper concerns the development of a new rather inexpensive frictionviscoelastic damper and its application in a damping system for base isolation of a structure. Earthquake mitigation study on viscoelastic dampers for. These dampers suppress bending and torsionmode blade vibrations, which are excited by unsteady aerodynamic forces during operation.
Influence of damping systems on building structures subject. Damping dissipation viscoelastic dampers reduce vibrations by converting kinetic energy into heat thus damping the motion of the system. Comparative study on the efficiency of friction and viscoelastic dampers. The viscoelastic structural damper application can perform the timedomain and frequencydomain analyses for a typical viscoelastic damper. Design and implementation of tuned viscoelastic dampers for. Energy dissipation dampers free download as powerpoint presentation. Pdf download for study on mechanical properties of high damping. A new configuration of coretubes with semiflexible suspension systems csfss is presented in this paper. Omid ranaei and ali akbar aghakouchak, a new hybrid energy dissipation system with viscoelastic and flexural yielding strips dampers for multilevel vibration control, archives of civil and mechanical engineering, 10. This paper is intended to introduce the results of the experiment and provide an overview of the product. Therefore, the amount of normal strain of each specimen is.
In the rubbery region, the material reaches a lower plateau in stiffness. Optimal design of viscoelastic dampers in frame structures. This project deals with the study of behavior of the building with viscoelastic dampers, making it earthquake resistant. Comparative analysis of a multistorey building with and without. In suppressing vibrations, these dampers reduce fatigue thereby prolonging blade lifetimes while reducing. The test was conducted on an electrohydraulic servo. The evaluation of steel frame structures with viscoelastic. The preload is obtained by screws that compress the specimens by a quantity. Simple viscoelastic dampers have been invented for use on the root attachments of turbomachine blades. Jun 01, 2017 viscous fluid dampers vfds and viscoelastic ve solid dampers belong to rate dependent passive dampers. The model allows viscoelastic material functions to be readily determined either directly from the experimental data or through interconversion from a function established in another domain. Detailed computational procedures for fitting and interconversion are discussed and illustrated.
Optimal seismic retrofit of fractional viscoelastic dampers. Introduction damped outrigger concept to mitigate wind vibrations in tall buildings the st. The seismic response control of multistory frame structures using optimally placed viscoelastic dampers veds within consideration of soilstructure interaction ssi effect is investigated in this paper. Continuous improvements in the techniques of identification and analysis, in fact, paralleled by noticeable refinements of device hardware, made the use of viscoelastic dampers. Use of viscoelastic dampers in reducing wind and earthquakeinduced motion. To clarify the mechanical properties of ve dampers, a new mathematical model, named the equivalent fractional kelvin model, which considers temperature and. The feasibility of using viscoelastic ve dampers to mitigate earthquake. Seismic response of steel frame structures with added. Life cycle testing of viscoelastic material for hubble space. Two viscoelastic specimens, parts 3 and 5, are cylinders mounted in parallel inside the preload device composed of parts 1, 2, 4 and 6, as shown in fig. Dampers viscoelastic tuned mass dampers tmds use viscoelastic ve material as the suspension element, in such a way that the material exhibits the functionality of both the energy dissipation device viscous and the restoring device elastic. Modeling of a viscoelastic damper and its application in. Traditional approach to controlling vibration in a milling system is to develop control mechanisms for cutting.
At the same time, 52 viscoelastic dampers are applied for seismic retrofit design on xian petrol hotel, and the finite analysis for structures with and without dampers are carried out under frequentearthquake and infrequentearthquake excitations. This paper presented temperature scanning tests of the viscoelastic materials firstly. Pdf performance based placement of viscoelastic dampers in an. Read our whitepaper to learn more about the features of mechanical, pneumatic, hydraulic, and elastomeric material dampers.
Design and implementation of tuned viscoelastic dampers for vibration control in milling. Pdf modeling of a viscoelastic damper and its application. Seismic response of structures with added viscoelastic dampers. International journal of machine tools and manufacture. Viscoelastic dampers are frequently used to protect tall structures against vibration. Mechanical pneumatic and material dampers sorbothane. Viscoelastic tuned mass dampers tmds use viscoelastic ve material as the suspension element, in such a way that the material exhibits the functionality of both the energy dissipation device viscous and the restoring device elastic. Material dampers apply to an array of industrial applications.
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