Friction Damper Research Articles

Experimental study on a steel self-centering rocking column with SMA slip friction dampers

This paper investigates the cyclic behavior of a steel self-centering (SC) rocking column. The steel SC rocking column consists of an H-section steel column and a pair of shape memory alloy (SMA) slip-friction dampers (SMASFDs). As the kernel part, the SMASFDs enhance SC capability of the rocking column and dissipate the input energy. The working principle of the rocking column is first described, along with the analytical equations that govern the behavior under loading cycles, which are validated by experimental data. The component tests were conducted on the NiTi SMA bar and the slip-friction mechanism, separately. And then, the cyclic loading tests were conducted on a 1:2-scaled rocking column specimen. The considered axial force ratio included 0, 0.1 and 0.2. During the entire experimental procedure, the SMA bars were neither repaired nor replaced. It is found that up to a drift ratio of 7 %, the rocking column maintained stable flag-shaped hysteresis, which is characterized by excellent SC capability and satisfactory damping capacity. The testing results also indicated that increasing axial force ratio effectively increased the strength and stiffness of the rocking column, whereas it reduced the post-decompression stiffness due to the P-Δ effect. Finally, the numerical models were established in ABAQUS and OpenSees, both of which were verified by the experimental data, and a parametric study was carried out.

Parametrized multi-objective seismic optimization for precast concrete frame with a novel post-tensioned energy dissipation beam-column joint

From the aspects of earthquake resilience, energy dissipation efficiency and building functionality, a novel post-tensioned energy dissipation (NPTED) joint with replaceable rhombus driving friction (RDF) damper is developed. To reach a well-balanced design scheme of a precast concrete (PC) frame with the NPTED joints, a multi-objective seismic optimization strategy with the dual concern of material cost and energy dissipation is put forward. The hysteretic behavior of the RDF damper is analytically derived, tested and numerically implemented into a finite element platform as a uniaxial material with the NPTED joint. To respond to the optimization problem in a more efficient way, the non-dominated sorting genetic algorithm (NSGA-II) is modified to improve the quality of population. The development of some interfaces and batteries within the finite element analytical platform and Grasshopper® makes the parametrized modeling and structural finite element analysis be automated during the optimization process. The effectiveness of the proposed optimization strategy, as well as the NPTED joints, has been fully demonstrated by a case study on a 12-story PC frame. The results indicate that the seismic design of those performance-dominant cases is controlled by rare-level earthquake while that of those cost-dominant ones is controlled by frequent-level earthquake.

Study on the high‐temperature damping properties of silicone rubber modified by boron‐terminated polysiloxane

AbstractRubber damping materials have important applications in modern industrial systems. However, their damping temperature range is low, which is not suitable for the damping demand under high temperature conditions. At present, there is very little research on the damping performance of rubber under high temperature conditions. Silicone rubber has excellent high temperature resistance but poor damping in its application temperature range. In this study, a boron‐terminated polysiloxane (PBS) was prepared by modifying hydroxy‐terminated polydimethylsiloxane (PDMS‐OH) with boric acid (BA). The molecular structure of PBS was confirmed by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) analysis. Rheology measurements revealed that PBS was a “shear hardening” material. Then, the silicone rubber was modified with PBS. With the introduction of boron atoms, boron and oxygen dative bonds with dynamic properties could be formed inside the silicone rubber, which played an energy dissipation role in the process of association/dissociation. Dynamic mechanical analysis (DMA) showed that the loss factor (tan δ) of modified silicone rubber was greater than 0.3 in the temperature range of 81.5°C–250°C, which was higher than the loss temperature range of conventional damping rubber. The cyclic stress–strain test also showed that the modified silicone rubber still had high dissipation coefficient (DE) at high temperature. Therefore, the PBS‐modified silicone rubber prepared by this method achieved excellent damping performance under high temperature conditions.

Longitudinal Vibration Transmission Control of Marine Propulsion Shafting with Friction Damper Integrated into the Thrust Bearing

Propeller-induced longitudinal vibration resonance in marine propulsion shafting systems causes great harm to the hull structure and is the primary source of shipboard noise. Integrating a friction damper with designed parameters into thrust bearings can prevent these issues. To investigate the performance of the damper-integrated thrust bearing in longitudinal vibration transmission control, an experimental and theoretical study is carried out in a laboratory-assembled test rig, which consists of components similar to the existing marine propulsion system. We developed a prototype of a thrust bearing designed with a friction-damping generation that allows switching from two supporting states, i.e., damper-connected and damper-disconnected states. Furthermore, a nonlinear analysis method for friction dampers is proposed. By this method, the way in which the friction damper changes the dynamic characteristics of the shafting system is analyzed. Based on the test rig, the acceleration frequency response function (AFRF) of the thrust bearing with and without a friction damper is measured. By comparison, the effectiveness of the friction damper is proved. The experimental results show that the friction damper suppresses the shafting longitudinal vibration response in a broadband frequency range and also confirms the stability of the damping effect, which does not change with the shafting rotational speed or static thrust from the propeller.

Development of a shape memory alloy-based friction damper and its experimental characterization considering rate and temperature effects

A new hybrid shape memory alloy (SMA)-based damper was developed to address two major challenges for SMA-based seismic control devices: (i) insufficient force capacity for real-world application and (ii) relatively low energy dissipation capacity. The hybrid damper, named Superelastic Friction Damper (SFD), leverages the high tensile resistance and excellent self-centering capability of SMA cables and non-sacrificial energy dissipation of a frictional damping mechanism. In this paper, the components and basic working principle of the proposed damper are first described, and the advantages of the proposed damper compared to the existing SMA-based hybrid dampers are highlighted. Then, the fabrication of a prototype damper and its experimental testing are discussed. The mechanical response of the damper under repeated cyclic loading at various displacement amplitudes and loading rates is revealed. The effects of ambient temperature on the hysteretic behavior of the developed damper are explored. Results reveal that the proposed damper exhibits stable hysteretic behavior with negligible sensitivity to the loading rate and temperature. The damper provides an equivalent viscous damping of 12 %, accompanied by 89 % recovery of the peak damper displacement.

DEVELOPMENT OF KNEE-BRACE FRICTION DAMPER FOR MID-RISE TIMBER FRAME BUILDING

This study aims to develop a knee-brace friction damper for mid-rise timber frame buildings. First, time history seismic response analysis was conducted to investigate the performance of the damper to improve the seismic performance of a four-story timber building. Then, static cyclic loading test on a beam-column joint with/without a prototype friction damper was carried out to verify the effectiveness of the damper. It is found that the damper mitigates slip behavior and increases equivalent viscous damping ratio and equivalent stiffness.

Energy response of a passive variable friction damper and numerical simulation on the control effects for high‐rise buildings

In this study, the behavior of a passive displacement-dependent variable friction damper (VFD) was evaluated. The energy response behavior of a VFD specimen was investigated by conducting full-scale dynamic loading tests. Full-scale tests demonstrated that the VFD specimen produced a lower sliding force when the device response exceeded a predetermined displacement, resulting in a decreased dissipated energy ratio as the displacement increased. The VFD specimen exhibited stable energy response behavior as well as a stable friction sliding force and friction coefficient under sinusoidal, seismic response, and 100-cycle loadings. The energy response of the VFD specimen was almost independent of the loading frequency. Moreover, a response simulation was conducted using a two-dimensional 30-story nonlinear mainframe model with brace-type VFDs under various input motions, including observation records and long-period, long-duration waves. From the numerical simulations, the peak story drift in the case with brace-type VFDs was not significantly greater than in the case with conventional friction dampers (FDs). The dissipated energy ratios of the mainframe and dampers in the case with the VFDs were approximately identical to those in the case with the FDs. In comparison with conventional FDs, VFDs can produce a lower peak story shear force and axial compressive force in the lowest-story columns at the device installation span.

An Experimental Investigation on the Dynamic Response Variability of a Turbine Blade With Midspan Dampers

Abstract This paper addresses two main subjects. First, a novel test setup is described to experimentally study the nonlinear dynamic behavior of a turbine blade coupled with two midspan dampers (MSDs). To this end, a representative turbine blade and midspan friction dampers are originally designed, and they are assembled to a special test rig which has been previously developed at Politecnico di Torino. Second, the variability of the dynamic response is intensively investigated with a purposely defined loading/unloading strategy. To better understand the inherent kinematics of the blade–damper interaction, contact forces are measured through the novel design of the experimental campaign. It is shown that multiple responses, which are obtained in different tests while keeping all user-controlled inputs nominally same, are due to nonunique contact forces that provide different static force equilibria on the damper. This outcome is further supported by the qualitative illustration of hysteresis cycles. This study contributes to the understanding of the response repeatability linked to the nonuniqueness of friction forces.

Nonlinear dynamics of friction-induced regenerative chatter in internal turning with process damping forces

Stability in internal turning operation depends on several factors such as cutting conditions, tool overhang, associated tool dynamics, regeneration, friction and process damping. In the present work, an improved friction-induced regenerative chatter mechanism is introduced for internal turning operations with the help of a two-degree of freedom (DOF) cutting tool model by considering structural nonlinearities and process damping effects. The model is initially validated with the existing linear stability analysis theory via the natural parameter continuation method. The stability lobes obtained from the proposed model predict the stable regions with good accuracy. Furthermore, the nonlinear behaviour of the cutting tool with Stribeck and regenerative effects under internal resonance and primary resonance conditions is investigated. The nonlinear dynamic responses and the cutting stability are predicted using the higher-order method of multiple time scales (MMTS). The effect of nonlinearities on the frequency response and stability is studied in detail and the system parameters for stable cutting operations are identified. In order to validate the cutting states of the stability diagrams, internal turning experiments are performed on AISI 1020 carbon steel workpieces and the stability conditions are found to be in good agreement.

A force-resisting rotary friction damper (RFD): Verification and comparison with traditional RFD

A force-resisting rotary friction damper (RFD) is proposed in this paper, which can be applied where there is a large rotational deformation. Its exclusive configuration lies in that multiple bolts are symmetrically arranged on concentric circles centered on the hinge pin to apply preload, resulting in: [i] an independent force-transfer capability decoupled with the moment to meet shear or axial forces-transfer demands and [ii] providing larger friction bending-moment with smaller compressive stresses on friction shim and lower maximum stress on the steel plate compared to the traditional RFD under the same preload and friction coefficient. A prototype of the proposed RFD was manufactured and tested twice without tightening the bolts again and replacing the friction shims by cyclic loading to investigate its mechanical property and recoverability. The test results showed that the moment–angle hysteretic curve of the proposed RFD was an ideal rectangle, indicating a reasonable mechanism. The variation of the friction bending-moment was within 4.00 % between the two-time tests, indicating that the proposed RFD has satisfactory recoverability and can uninterruptedly provide energy absorption during dense aftershocks. Then, a refined finite element model was established and calibrated by the test results. For the numerical prototype studied, the friction bending-moment of the proposed RFD was approximately 35 % larger than that of the traditional RFD while its maximum pressure on friction shim was about 40 % of the corresponding traditional RFD. The difference in the friction moment between the theoretical and numerical results was within 4.50 %. The concept of the force-resisting RFD was justified.

Approximating nonlinear response to harmonic base-excitation using fixed-interface quasi-static modal analysis

The recently developed quasi-static modal analysis (QSMA) technique approximates the amplitude dependent modal characteristics of large-scale finite element models with frictional contact at preloaded interfaces. The nonlinear natural frequencies and damping ratios offer insight into the dynamic behavior of assembled structures, particularly the amount of frictional damping and stiffness loss introduced from an isolated modal oscillation due to the joints. This work presents an approach to approximate the nonlinear steady-state response of a base-excited structure using the nonlinear frequency and damping estimates from QSMA. A Hurty/Craig-Bampton transformation allows for the base-excited system to be expressed in terms of the fixed-interface modal coordinates, thus allowing the extension of previously developed analytical approximations using the prescribed base acceleration and the nonlinear, fixed-interface modes from QSMA. The accuracy and relevance of this non-intrusive approach rely on the applicability of Masing's hypothesis within QSMA to approximate the hysteresis curves from the initial loading curve. The limitations are investigated by considering both Masing and non-Masing joint models. A comparison to reference solutions demonstrates the accuracy of the approximation to efficiently obtain nonlinear steady-state solutions of large-scale models with frictional interfaces for cases that satisfy Masing's hypothesis.

Fractional Nonlinearity for the Wave Equation with Friction and Viscoelastic Damping

In this paper we consider a fractional nonlinearity for the wave equation with friction and viscoelastic damping. Using Fixed point theorem a global in time existence of small data solutions to the Cauchy problem is investigated in this research. Our main interest is to show the influence of the fractional nonlinearity parameter to the admissible range of exponent ς comparing with power nonlinearity and also the generating of loss of decay.

Variable Friction Dampers (VFD) for a modulated mitigation of the seismic response of framed structures: Characteristics and design criteria

In this paper a new approach for the energy dissipation is discussed based on the use of Variable Friction Dampers (VFDs). The VFD device is borrowed from braking systems mechanical engineering, able to modulate its capability of dissipation, providing a constant pure friction force coupled with an additional (variable) damping force with the increasing of the displacement.Resorting to a previous study, the characteristics and the efficiency of the “braking” system in terms of reduction of the displacements and the restoring forces is described for SDOF systems under seismic excitations and compared with the performances achievable by classic constant friction dampers (CFDs). Then, a design criterium based on structure stiffness, viscous damping and seismic demand is proposed evaluating its effectiveness through a statistical assessment of the dynamic response of SDOF models subjected to natural accelerograms.The results obtained by the proposed design approach have proven that is a robust approach and indicate that the device can be really considered suitable for the improvement of the energy dissipation and the reduction of the drift in framed structures in an extended range of the seismic demands (from low to high) differently from the classic friction devices whose characteristics make them effective in a smaller range of the seismic intensities.

Meta-interface textures for increased frictional damping in elastic structures

The unique behavior of acoustic and elastic metamaterials results from engineered subwavelength material composition and geometry. Though there has been a profusion of metamaterial research over the last two decades, relatively little focus has been on the dissipation of vibro-acoustic energy. Most research on metamaterials for acoustic damping have focused on viscous or viscoelastic effects [1]. However, the design of interfaces within materials or at connecting surfaces between elastic structures to amplify micro-friction events due to the relative motion of contacting surfaces is of interest for the reduction of vibro-acoustic energy. Dissipation due to friction is best represented as a nonlinear constitutive response. Here, we report on the use of friction via meta-interface textures to create interfaces with elevated damping, leading to increased macroscopic dissipation. We employ the five-parameter Bouc-Wen model to describe the complex behavior at these interfaces and study the influence of subwavelength interface texture on the parameters of the friction model. This increased dissipation from this approach can be used to reduce structural vibrations and the transmission of acoustical energy in structural components. [1] C. L. Bacquet et al., “Metadamping: Dissipation emergence in elastic metamaterials.” Adv. App. Mech. 51, 115i–164, (2018).

A numerical solution for seismic response prediction of bridge piers with high damping rubber bearings

The motion equation of a one-degree-of-freedom system when subjected to earthquakes is usually not solved by analytic methods. This problem can only be solved through the time step method, when integrating differential equations. This paper is devoted to presenting a numerical solution for a seismic analysis problem of a highway bridge pier with high damping rubber bearings under earthquakes. Based on time-stepping Newmark’s method, a numerical solution is developed to predict the seismic responses of the piers. The iteration Newton-Raphson method is also applied in the problem for static analysis of this nonlinear system. The ground acceleration in the analysis is the type- II earthquake in JRA 2004 (Japan Road Association). Further-more, high damping rubber bearings are modeled by the two models: the bilinear design model and the rheology model proposed by authors. After that, the stress responses and the displacement responses of the pier are obtained by a program that is implemented in Matlab software. The comparison results obtained from the two models show that the seismic responses of the pier strongly depend on the modeling of the rubber bearings. This is the important note for engineers to design the earthquake resistance of bridges with high damping rubber bearings. The solution is also a useful tool for engineers to predict the seismic responses of bridge piers in the design procedure.

Semi-active control of crankshaft skyhook based on magnetorheological torsional damper

The purpose of this study was to solve the problem that the damping of rubber or silicone oil torsional dampers used in crankshafts is not adjustable and cannot effectively control torsional vibration at different resonant frequencies. Based on the controlled rheological properties of magnetorheological (MR) smart materials, this study designed a new type of variable damping MR torsional damper (MRTD) and proposed a semi-active control method to effectively control the torsional vibration of the crankshaft under multiple harmonic resonances. First, a mechanical model of the MRTD and a lumped parametric mass model of the crankshaft system were developed, and the resonance frequency harmonic range of the crankshaft system operation was determined by the torsional vibration characteristics analysis. Then a semi-active skyhook control method for the MRTD was proposed, and a joint control simulation analysis was performed using Amesim and Matlab software. The torsional vibration control effects of the crankshaft system with no damper, MRTD with different damping coefficients, and MRTD with skyhook control under acceleration and uniform speed conditions were comprehensively investigated. The simulation results indicated that the skyhook damping control significantly reduced the torsional vibration amplitude under both acceleration and uniform speed conditions, verifying the effectiveness of the skyhook-based control strategy for MRTD.

A shallow cable with a tuned mass-high damping rubber damper

Tuned mass-high damping rubber damper (TM-HDR-D), as a high-efficiency damper, has great practical feasibility and good application prospect for cable vibration mitigation. To investigate the effect of TM-HDR-D on the cable dynamics, a refined model which considers the cable sag effect is established via complex modal method. Then, based on this model, the influence of cable sag and the stiffness, location, loss factor, and mass of the TM-HDR-D on the cable dynamics is systematically investigated. Meanwhile, the multi-mode damping effect of TM-HDR-D is also analyzed. Results show that TM-HDR-D can significantly increase the additional damping of the system. The cable sag only affects the first-order modal damping, and the effect of TM-HDR-D is significantly affected by its frequency, loss factor, and installation position. Improving the mass of the damper can improve the damping effect. Reasonable selection of damper tuning frequency can achieve multi-order modal damping enhancement.

Hysteretic behavior of high damping rubber bearings under multiaxial excitation

The high damping rubber bearing (HDRB) is an advanced seismic isolation component currently used in building structures with excellent energy dissipation capacity. To explore a deeper understanding of the HDRBs’ performance and effectiveness, a series of six-degree-of-freedom (6DOF) quasi-static tests were designed and conducted on three HDRB specimens with different dimensions. The main purposes of the tests are to reveal the hysteresis characteristics of the bearings in the rotational degrees of freedom, and to assess the influence of axial pressure and multiaxial coupling effect on the horizontal performance of the HDRBs. During the tests, the rotational, unidirectional, and bidirectional horizontal (coupled and uncoupled) hysteretic responses were obtained. Additionally, several important mechanical parameters are recommended and calculated to evaluate the coupling effect of axial load and rotation on HDRB performance. The results indicate that the axial pressure has a significant impact on the horizontal performance, while the effect of coupling the rotational degrees of freedom is not obvious. In addition, the tests also observed a significant level of stiffness degradation in the horizontal directions after multiple loading cycles.

Seismic resilient rocking shear wall with dual self-centering energy dissipation system: Introduction and A preliminary study

In this paper, a new rocking shear wall with dual self-centering energy dissipation system is proposed for seismic resilient application. It mainly consists of pinned RC wall, pre-pressed disc spring friction damper (PDSFD) and pre-pressed disc spring brace with U-shaped steel damper (PDSBUSD), while the pinned wall with PDSFD located at the bottom (PDSFD-wall) and the PDSBUSD form the dual system to resist lateral load and dissipate energy. This study aims to introduce its details and preliminarily investigate the seismic performance. Firstly, mechanical models of PDSFD and PDSBUSD are revealed and reliable numerical models for them are built to analyze the hysteretic performance. Subsequently, theoretical skeleton model and design principle of PDSFD-wall component are derived, following which the cyclic behavior under different design parameters is numerically analyzed. Combined the above analyses, theoretical hysteresis model and design procedure of the presented rocking shear wall are given, and the influence of critical parameter on its cyclic behavior is discussed by performing numerical simulations. The results show that the theoretical hysteresis models are in accordance with the numerical results; by improving with PDSFD and PDSBUSD the bearing, energy dissipation and self-centering capacities are significantly enhanced, while the damage of RC wall is significantly reduced; the designed rocking shear walls exhibit desirable seismic resilience with about 80% of the energy dissipated by the replaceable friction and steel dampers, and the expected dual yielding energy dissipation mechanism is realized. During the design, it is suggested that the preload of PDSBUSD should be no less than the yielding strength of the steel damper; the ratio of preload to friction force for PDSFD adopts 1.5; the ratio of lateral resistance contribution of PDSBUSD to PDSFD-wall adopts 0.2–0.5.

Evaluation of seismic response of coupled wall structure with self-centering and viscous damping composite coupling beams

In order to reduce the residual displacement and floor acceleration of coupled wall structures, a novel self-centering and viscous damping composite coupling beam is proposed. The proposed coupling beam consists of the elastic beam segments and the fuse part, which incorporates self-centering friction dampers and viscous dampers. The self-centering friction damper can provide strength and stiffness for the proposed coupling beam and reduce the residual displacement of the coupled wall structure. The viscous damper can add supplemental damping to the system, and this can control the peak lateral displacement demands and floor accelerations of the structure. Moreover, the proposed coupling beam can eliminate the beam elongation effect of the self-centering coupling beam with a rocking behavior. Design methodology and nonlinear numerical model of the proposed coupling beam are developed. The seismic behaviors of the coupled wall structure with the self-centering and viscous damping composite coupling beams (CW-SCVCCB) are assessed and compared with the structure with reinforced concrete coupling beams (CW-RCCB), the structure with steel coupling beams (CW-SCB) and the structure with self-centering coupling beams (CW-SCCB). Analysis results showed that the supplemental viscous damping can effectively reduce the peak interstory drift ratio and floor accelerations of the structure. The residual displacement of the novel coupled wall system is larger than that of the CW-SCCB, however, it is significantly reduced compared with the CW-SCB and the CW-RCCB.