High Damping Rubber Model for Energy Dissipating Devices

In this work the results of a study carried out to characterize the mechanical response of a high damping rubber to be used to design and construct energy dissipating devices and base isolators for controlling strong vibrations in civil engineering structures is presented. A new parametric model of the rubber is proposed to be employed in the design procedure and structural analysis of passive controlled structures. The parameters of the model are calibrated using experimental results obtained from tests on rubber specimens subjected to different loading paths. The response predicted by the proposed model is compared with these obtained from experimental tests.

2016

The elastomeric compensation device mounted between the vibrating base and protecting object is the main element of any the passive vibration protection system. Rubber and rubber-like materials (elastomers) are the most suitable material for such devices due to their capability of absorbing input energy much better than other construction materials. In this paper rubber absorber of prismatic form with parallel flat ends under axial harmonic kinematic excitation is considered. For the estimation of damping properties of the rubber vibroabsorber two approaches are applied: using the mechanical models based on combination of elastic and viscous elements and using analytical representation of integral equations of creep and relaxation. In this article Maxwell and Burgers mechanical models and Rabotnov’s kernel for analytical representation are used. Damping properties are expressed by the ratio of amplitude of the driving vibration to the amplitude of the forced oscillations of object. ...

Advances in Structural Engineering, 2012

A new vibration control system including viscoelastic or viscoplastic rubber dampers is proposed for residential houses. This system consists of braces and a damper unit including a high-hardness rubber damper or a linear rubber damper. The high-hardness rubber damper possesses many unprecedented properties such as large stiffness, small temperature and frequency dependencies compared to most of usual viscoelastic dampers. Post tensioning forces are introduced into the braces to reduce small gap in joint parts and this system has high damping performance for micro-vibration. The control system can absorb sufficient energy through the high-rubber damper and post tensioning braces. A concept is introduced called an effective deformation ratio, i.e. the ratio of the actual damper deformation to the interstory drift of the frame, as a criterion to measure the damping performance and effectiveness of this system. To find out principal parameters that affect greatly the effective deformation ratio of the proposed new vibration control system, an incremental analysis method taking into account the geometrical and material nonlinearities is developed to simulate the main characteristics of this vibration control system. The accuracy of the analysis method is investigated through the comparison with the results by two simple analysis methods. The comparison with the experimental result is also conducted for further investigation.

Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference, 2015

Rubber and rubber-metal (RM) elements are successfully used as bearing, joints, compensating devices, vibration and shock absorbers in civil engineering and machine building because of rubber and rubberlike materials (elastomers) have a capability of absorbing input energy much better than other construction materials. The elastic properties of rubber in such supports allows reverse backward to its original position under dynamic load action. Along with the instantaneous elastic deformation these materials exhibit a retarded elastic deformation, viscous flow (creep) and relaxation. The mechanical properties of rubber which are necessary for the optimal design of antivibration devices are next: bulk modulus of compression, dynamic and static shear modulus, energy dissipation factor. To describe the relationship between the compressive (or shear) stress σ(t) and strain ԑ(t) the creep and relaxation kernel, taking into account the viscoelastic properties of the rubber, is used. The kernels proposed by A. Rzhanitsin, Y. Rabotnov, M. Koltunov give satisfactory results for the mechanical properties of rubber in the mean frequency domain (10-3 < ω < 10 3 s-1). In this paper for the accounting of dissipative properties of the rubber Rabotnov's kernel is used, the energy loss during one oscillation period is calculated. The flat-type RM absorber with kinematic excitation, which lower base oscillates harmonically is considered, oscillation parameters of the upper base on which the protected object is placed, are calculated. Damping properties are expressed by the ratio of the amplitude of the forced oscillations of the upper base (and object) to the amplitude of driving lower base.

The Abstracts of ATEM : International Conference on Advanced Technology in Experimental Mechanics : Asian Conference on Experimental Mechanics

Even though high damping rubber (HDR) is used in various fields such as vibration isolation and seismic isolation, few studies have been conducted to investigate thermo-mechanical behaviors. Besides, modeling on thermo-mechanical coupling is not available. This paper presents experimental investigations of temperature dependency behavior of HDR material and its thermo-mechanical constitutive modeling. The use of infrared thermographs to measure temperature field in HDR under cyclic shear is presented. Changes of mechanical properties of HDR are investigated with respect to frequency of loading and rubber body temperature. Based on the results of rubber material tests, a temperature dependent constitutive model for HDR is proposed, which combines elasto-plastic body with strain dependent isotropic hardening law and hyperelastic body with damage model. Temperature dependent parameters, which can express rate dependent hardening, yielding and thermal softening are introduced to the model. The proposed constitutive model can express both temperature dependent and frequency dependent behavior of HDR. Finally, the energy balance equation is constructed to evaluate average surface temperature of the material. The modeling results agree well with the experimental ones.

A new rubber-based isolation device, with added damping capacity, is proposed. Similarly to the LRB&#39;s (Lead Rubber Bearings) or HDRB&#39;s (High Damping Rubber Bearings), the proposed solution combines, in a single compact device, the functions of supporting vertical loads, providing horizontal flexibility and restoring force together with the function of dissipate a great amount of energy. On the other hand, the proposed device shows a series of advantages with respect to LRB&#39;s and HDRB&#39;s, which are herein properly discussed. A comprehensive program of experimental tests was carried out at the Structural Laboratory of the University of Basilicata, to characterize the mechanical behaviour of the new Added viscous Damping-Rubber-Isolator (ADRI). Several non linear numerical analysis were then carried out, in order to investigate the effectiveness of ADRI in reducing the response of seismically isolated bridges. In this paper the main results of both experimental tests and...

Vibroengineering PROCEDIA

The vibration dampers, shock absorbers, seismic isolation, bearing seals, compensation devices are widely applied in civil engineering, machine manufacturing and shipbuilding, aviation and aerospace engineering. For these details fabrication elastomeric materials are used. Rubber and rubber-like materials (elastomers) have the capability of absorbing input energy much better than other engineering materials. Elastomeric materials give many engineering advantages due to their high elasticity, good dynamic properties, low volume compressibility, a linear relationship between stress and strain at small and middle deformation, resistance to aggressive environmental factors. The disadvantage of elastomeric materials is ageing, i.e. changing their mechanical properties over time and lowering their operational capability. In given paper the influence of ageing of elastomeric materials on the damping properties of shock absorbers is considered based on the mechanical models of elastomers-Maxwell and Burgers modes.

19th International Scientific Conference Engineering for Rural Development Proceedings

Rubber and rubber-like materials (elastomers) are widely used for anti-vibration mounts and shock absorbers for vehicles, machinery, building structures due to their specific properties: ability to absorb vibration and shock loads, low elastic modulus, high mechanical strength, high elongation at brake, reversible elastic deformation. Rubber is a material that is capable of recovering from large deformations quickly and forcibly, which is suitable for work under cyclic loading. During deformation elastomeric materials absorb in an irreversible way part of the energy, causing this deformation. The energy absorbed during each cycle heats the deformed rubber element and dissipates in media. Heat generation in rubber causes additional stresses and deformations which are poorly known, and they are a subject of our study. In the presented paper the work of a rubber anti-vibration mount in the form of a straight circular cylinder under action of cyclic loading is studied. Poisson's ratio of the rubber material is μ = 0.5, the weight of the mount is not taken into account. Temperature field is assumed known based on the previous work (it depends on the frequency and amplitude of vibration, heat conductivity and heat capacity of the material, etc.). The stress-strain state analysis was carried out based on the Reissner variational principle. Analytical dependences for temperature additions to stresses and displacements are derived that allows estimating stiffness of the anti-vibration mount and its increase as a result of self-heating. Obtained results may be useful for proper design of anti-vibration mounts allowing changing geometrical dimensions in order to reach the required temperature field.

Plos One, 2017

Conventional seismic rehabilitation methods may not be suitable for some buildings owing to their high cost and time-consuming foundation work. In recent years, viscoelastic damp-ers (VEDs) have been widely used in many mid-and high-rise buildings. This study introduces a viscoelastic passive control system called rotary rubber braced damper (RRBD). The RRBD is an economical, lightweight, and easy-to-assemble device. A finite element model considering nonlinearity, large deformation, and material damage is developed to conduct a parametric study on different damper sizes under pushover cyclic loading. The fundamental characteristics of this VED system are clarified by analyzing building structures under cyclic loading. The result show excellent energy absorption and stable hysteresis loops in all specimens. Additionally, by using a sinusoidal shaking table test, the effectiveness of the RRBD to manage the response displacement and acceleration of steel frames is considered. The RRBD functioned at early stages of lateral displacement, indicating that the system is effective for all levels of vibration. Moreover, the proposed damper shows significantly better performance in terms of the column compression force resulting from the brace action compared to chevron bracing (CB).

This is the first of two companion articles addressing an integrated study on the mathematical modeling and assessment of the efficiency of surface mounted or embedded viscoelastic damping treatments, typically used to reduce structural vibration and/or noise radiation from structures, incorporating the adequate use and development of viscoelastic (arbitrary frequency dependent) damping models, along with their finite element (FE) implementation, and the experimental identification of the constitutive behavior of viscoelastic materials. This first article (Part I) is devoted to the development of mathematical descriptions of material damping to represent the linear viscoelastic constitutive behavior, their implementation into FE formulations and the use of the underlying different solution methods. To this end, internal variables models, such as the Golla-Hughes-McTavish (GHM) and anelastic displacement fields (ADF) models, and other methods such as the direct frequency response (DFR), based on the complex modulus approach (CMA), iterative modal strain energy (IMSE) and an approach based on an iterative complex eigensolution (ICE) are described and implemented at the global FE model level. The experimental identification of viscoelastic materials properties and the aforementioned viscoelastically damped FE modeling approaches are assessed and validated in the companion article [Vasques, C.M.A. et al., Viscoelastic damping technologies-Part II: Experimental identification procedure and validation, Journal of Advanced Research in Mechanical Engineering 1(2): 96-110 (2010)].