Damping Control Research Articles

Performance Evaluation of Inerter and Negative Stiffness-Based Dampers for Seismic-Induced Vibration Response Control of a Cable-Stayed Bridge: A Comparative Study

The excessive main girder displacement responses of the large-span cable-stayed bridges during seismic events may precipitate collisions between the main girder and the approach bridge. The viscous dampers (VDs) have been extensively employed in the seismic response control of long-span bridges, yet their effectiveness is limited. To augment the seismic-induced vibration control performance of the VD, inerter element, negative stiffness (NS) element, and spring element have been incorporated into the VD to achieve energy dissipation capacity enhancement. The equations of motion for the simplified cable-stayed bridge-damper systems are established under stochastic seismic excitation, and the design parameters of inerter and NS-based damper are optimized by using the genetic algorithm. The seismic control performance of the VD and five types of dampers are systematically compared, demonstrating that these dampers can substantially enhance the main girder displacement mitigation performance in cable-stayed bridges. Owing to the NS characteristics attributes of the inerter element and NS element and the tuning effect of the spring element, the tuned viscous mass damper (TVMD) with NS achieves a 24.56% higher efficiency in control performance compared to the VD.

Semi-Active Suspension Design for Truck Using Pneumatic Spring Joining MR Fluid Damper Based on Neural Networks Controller

<div>In order to modify both stiffness and damping rates according to various road conditions, this research introduces a pneumatic spring in conjunction with a magnetorheological (MR) fluid damper as a single suspension unit for each wheel in the truck. Preventing weight transfer and improving riding comfort during braking, acceleration, and trajectory prediction are the main objectives. A two-axle truck has been used, consisting of three degrees of freedom for the sprung mass, including vertical, pitch, and roll motions, and four degrees of freedom for the unsprung masses, which have been redesigned according to the different types of springs and dampers. Pneumatic-controlled springs, often referred to as dynamic or classic models, replace laminated leaf springs commonly found in vehicles. Additionally, an MR damper replaces a hydraulic double-acting telescopic shock absorber. These models are studied to evaluate the effect of pneumatic spring parameters on truck dynamics. Pneumatic stiffness and the intended damping force are monitored by a recurrent neural network in conjunction with leveling control. This process provides the recommended voltage for the MR damper based on the Signum function damper controller. The performance of the suspension is assessed in the time and frequency domains for both step and random road excitations using vehicle dynamic parameters. Six suspension system configurations are compared with the air spring dynamic model integrated with the MR damper (Model 6), which is recommended as a suspension system for trucks. According to simulation data, when compared to alternative suspension systems, Model 6 significantly enhances both ride comfort and vehicle stability. Model 6 offers improvements in tire workload, truck path, tire–ground contact point during acceleration, braking efficiency, and stopping distance. Compared to previous controlled models, Model 6 also demonstrates zero steady-state offset and zero steady-state error.</div>

A novel robust active damping control strategy based on H∞ loop shaping for the grid-tied LCL inverter

LCL-type grid-connected inverters have been widely used in renewable power generation due to their size and cost advantages. However, the LCL filter has a problem of insufficient damping, which may lead to power system instability. Two common methods are used to address this problem: passive damping (PD) and active damping (AD). PD methods suppress resonance by adding resistors to the LCL filter, but this approach increases system losses. AD methods enhance damping through control to suppress resonance. Existing AD methods are often significantly affected by grid-side inductance perturbation, resulting in insufficient robustness. To address this issue, this article proposes a novel robust active damping (RAD) control strategy based on H∞ loop shaping. Simulation analysis and experimental research show that the RAD control method exhibits superior robustness compared with the traditional capacitor current active damping control.

Theoretical and experimental investigation of flexible air spring stiffness in a tuned liquid column gas damper for vertical vibration control

This study investigates the effectiveness of equivalent linear air spring stiffness in a Vertical Tuned Liquid Column Gas Damper (VTLCGD) for reducing vertical structural vibrations, particularly considering different sealing conditions. The VTLCGD system, designed with a single sealed vertical air column, allows flexible frequency tuning by adjusting the air spring stiffness. It aims to be used in low-frequency structures where conventional VTLCGD designs with two sealed ends are less efficient. The geometric configuration and working principle of the VTLCGD are first described. The equation of motion is derived using liquid dynamic equilibrium and the pressure-volume relationship, with expressions for natural frequency and control force validated through shaking table tests conducted with varying VTLCGD lengths. Experimental investigations are conducted to examine the parameters affecting damper performance using pressure data. The system's vibration reduction performance is then numerically evaluated on a cantilevered floor subjected to human walking. The numerical results, based on the equation of motion for liquid displacement and natural frequency, show good agreement with experimental data, which confirms the effectiveness of using linearized air spring stiffness for frequency tuning. The effects of total liquid length and height difference on control force are further investigated, and a polytropic index of 1.2 is determined for the VTLCGD frequency formula. The VTLCGD system achieves a maximum vibration reduction of 52.63 % in acceleration response on the cantilevered floor compared to the uncontrolled case. Moreover, the variation in stiffness due to changes in the sealing condition is presented to validate the damper's adaptability over a wide frequency range.

Uplift derailment for near-fault high speed train-track-hybrid control cable-stayed bridge system

Seismic uplift of a high-speed rail (HSR) cable-stayed bridge’s bearing affects train safety. Existing technique lacks improved seismic isolation in the vertical direction due to the bearing’s vertical stiffness. Based on the on-site dynamic test and train derailment table experiments and different software, the train running safety of the semi-floating system of the cable-stayed bridge-rail-train system was analyzed using different damping and isolation control strategies. The larger vertical seismic component increases the danger of flange climb derailment when subjected to near-fault earthquakes. After installing lateral/or viscous fluid dampers (VFDs) and magnetorheological (MR) bearing (A = 3.0), the bridge has an obvious bearing uplift response. Still, it is not enough to threaten the structure, and the seismic damping capacity of the bridge structure is improved, making the train ride safe. This research presents discoveries on the impact of bearing uplift on train operational safety. Specifically, it reveals that the lifting of the end bearings on both sides of the main girder is not synchronized. This investigation presents a technical reference for comparable initiatives.

A variable damping viscous damper for control of buildings under wind loading

High-rise buildings are susceptible to low-frequency vibrations induced by wind loading, and the traditional constant damping viscous damper (CDVD) falls short in effectively suppressing vibrations of high-rise buildings under wind loadings because of its constant damping coefficient. To address this, a novel variable damping viscous damper (VDVD) is first designed and fabricated. The characterization tests were conducted to evaluate the variable damping characteristics under different velocities. The control performance of the VDVD in high-rise buildings under wind loadings with varying wind pressures is simulated and analysed, as comparisons with CDVD. The test results show that the damping coefficient of the VDVD increases with the input velocity. Furthermore, it exhibits the capability to achieve both constant and variable damping through the adjustment of the pre-pressure force in the spring. Compared with cases using CDVD, the VDVD demonstrates a significantly greater reduction in structural response, with cumulative dissipated energy ratios ranging from 1.0 to 3.14 as wind pressure increases. The VDVD offers excellent potential for various engineering applications in terms of new concepts and new devices for vibration control and mitigation induced by wind loadings.

Reprogramming multi-stable snapping and energy dissipation in origami metamaterials through panel confinement.

With a focus on a class of origami-inspired metamaterials, this work explores the role of panel confinement in their mechanical response under cyclic loading. The goal is twofold: (i) quantify the magnitude change in snapping force and energy dissipation attained by varying the severity of confinement of selected panels; and (ii) leverage insights to modulate in situ their mechanical response as dictated by a given application, hence propose panel confinement modulation as a practical design route for response reprogrammability. Through computational modelling, proof-of-concept fabrication and cyclic testing, we first identify and characterize the governing factors enabling either the alteration or the preservation of the snapping force magnitude during repeated cycles of forward and backward loading. Then, we demonstrate how the in situ modulation of the constrained distance between selected panels enables reprogramming their snapping sequence and energy dissipation. The results contribute to expanding the versatility and application of this class of origami metamaterial across sectors, from aerospace to protective equipment, requiring precise control of mechanical damping and energy dissipation.This article is part of the theme issue 'Origami/Kirigami-inspired structures: from fundamentals to applications'.

Validation of a three-dimensional finite element constitutive modeling approach for a thermoplastic polyurethane calibrated with uniaxial tests

This paper presents the three-dimensional finite element constitutive modeling validation for a Thermoplastic Poly-Urethane (TPU) material. The material parameters are those given in a previous study obtained by calibrating the constitutive model with uniaxial material-level test results (1-D tensile and compression tests). Confined compression tests were performed to estimate the bulk modulus for more accurate material characterization. The parameters were validated by comparing the results of experimental tests on TPU components with those obtained by its equivalent finite element simulations. The TPU component tests comprised cyclic compression tests of (i) a TPU cylinder, (ii) a solid 100 mm diameter TPU ball, and (iii) a 100 mm diameter TPU ball with an 80 mm steel core. In all tests, the constitutive model parameters showed an excellent performance in representing the mechanical behavior of the material observed in the tests, including the nonlinear stiffness and hysteresis. Finally, a brief case study is presented to illustrate the applicability of the validated constitutive model parameters in modeling a novel TPU damper for structural control before its manufacturing and experimental testing. The validated constitutive modeling approach and available material parameters will allow the performance of reliable and early-stage finite element simulations to prototype the mechanical behavior of TPU components of different shapes and boundary conditions and thus gain relevant insight into the component level response before manufacturing and testing.

Experimental study of rotational friction damper for seismic response control: friction material comparison and configuration optimization

Rotational friction dampers (RFDs) can be incorporated into structures flexibly as energy-dissipation devices for seismic response control. However, the basic primary form of RFD has three main challenges and objectives in enhancing its performance: (1) avoiding strength fluctuation and jittering, namely, improving the stability of the performance, (2) enhancing the strength, and (3) relieving the basic assumption that the clamping pressure is uniformly distributed on the friction pads and ensuring the accuracy of the theoretical equation. To address these issues, this study proposes four potential approaches: (1) selecting a friction material with a stable performance, (2) increasing the friction coefficient, (3) increasing the clamping force, and (4) optimizing key configurations. Based on these concepts, two sets of experimental studies, including 27 friction pad material comparison tests and 17 lug plate and clamping bolt configuration optimization tests, were conducted. According to the test results, the fiber-reinforced resin-based composite (FRRC) material was found to be better than H62 brass and 7075 aluminum alloy in realizing a high friction coefficient and stable performance, as well as achieving uniformly distributed pressure. The four-bolt lug plate and six-bolt lug plate with stiffening ribs were found to be effective in realizing a high clamping force and, thus, a high RFD strength, as well as in achieving a uniformly distributed pressure. In contrast, the single-bolt lug plate could not realize a high clamping force because of the tightening torque limit. A six-bolt lug plate can cause pressure concentration and edge damage to the friction pad.

Application of conical spring to maintain tuning of mass damper for wave-induced vibration control of offshore jacket platform subjected to changes in natural frequency

Offshore jacket platforms are situated in challenging environmental conditions and often experience changes in mass and stiffness, resulting in alteration in its dynamic properties. The tuned mass damper (TMD), known for its effectiveness in vibration control, has been earlier studied for implementation in jacket platforms. However, it is sensitive to tuning and would suffer a performance loss if the structural frequency undergoes modification. This can be overcome by connecting the damper mass to the structure by a conical spring that exhibits multilinear behaviour. This allows the TMD to remain tuned to different values of the structural frequency. In this study, the jacket platform is modelled as a multi-degree-of-freedom (MDOF) system, and the performance of the designed TMD with conical spring (TMD-C) is investigated in both frequency and time domain. Two possible variations in the fundamental period of an example jacket structure are considered and the results of wave-induced vibration control of deck responses achieved by the TMD-C are compared with those by the conventional TMD. Results indicate that despite being a passive device, the TMD-C can maintain the desired tuning to the structural frequency and thereby outperforms the conventional TMD in the reduction of the deck responses.

Dynamic characteristics of a novel inerter-enhanced tuned mass damper for structural vibration control

Dynamic characteristics of a novel inerter-enhanced tuned mass damper for structural vibration control

Testing, Validation, and Simulation of a Novel Economizer Damper Control Strategy to Enhance HVAC System Efficiency

Buildings account for over 40% of global carbon dioxide (CO2) emissions, with supply and return fans in air handling units consuming a significant portion of energy. To address this, researchers have explored innovative economizer damper control methods and identified the “split-signal” strategy, which optimizes supply airflow using a single damper as a promising approach. In this study, split-signal was further refined for practical application and energy simulation, aiming to demonstrate its effectiveness and encourage adoption in real-world building mechanical systems. Laboratory testing on chilled water variable air volume (VAV) system showed fan energy savings of 0.2–5% compared to traditional “three-coupled” control, depending on ventilation air proportions, and prevented reverse airflow. A statistical regression model, based on experimental data, was developed to predict energy savings and streamline comparisons. Energy simulations were conducted across various U.S. climate zones and revealed potential savings of 15–20% in energy use, operational costs, and CO2 emissions. With minimal financial investment, split-signal control offers a cost-effective solution to improve energy efficiency and reduce environmental impact, promoting its adoption in real-world building applications.

The influence of semi-actively controlled magnetorheological bogie yaw dampers on the guiding behaviour of a railway vehicle in an S-curve: Simulation and on-track test

Many publications have shown that semi-actively controlled dampers could significantly improve the behaviour of a road or rail vehicle. In the case of a railway vehicle, these dampers promise to solve the contradiction between the damping requirements of different running modes (fast running on a straight track vs negotiating a tight curve). It is known that semi-active control of a bogie yaw damper can improve the vehicle behaviour when running fast on a straight track, but it is not known whether such semi-active control worsens the vehicle behaviour when negotiating a tight curve. This paper investigates the application of magnetorheological bogie yaw dampers in the locomotive bogie to reduce guiding forces and wear in wheel-rail contact when the vehicle negotiates the S-curve. The paper describes the magnetorheological damper, its mathematical model and the strategies for its semi-active control, followed by the results of simulations on a complex multi-body locomotive model and on-track testing on a real vehicle. The simulations and on-track tests have shown that the use of semi-active control of the yaw dampers reduces the guiding force by about 10%. The reduction in these forces will lead to a reduction in wear in the wheel-rail contact.

A study on the annular cylindrical tuned liquid damper for dynamic control of spar buoy based measurement system

A study on the annular cylindrical tuned liquid damper for dynamic control of spar buoy based measurement system

Performance of differently arranged double-tuned mass dampers for structural seismic response control including soil-structure interaction

Reducing vibrations occurring in structures under environmental loads makes a significant contribution to the development of structural safety. Tuned mass dampers (TMD) are one of the systems commonly used to control structural vibrations. Since TMD is adjusted according to the dominant frequency of the structure, factors that may cause changes in the frequency of the structure can significantly reduce the effectiveness of TMD. One of the main factors that can cause changes in the frequency values of the structure is the interaction between the structure and the soil. To overcome this situation, it is recommended to apply control systems consisting of multiple TMDs (MTMD) to the main structure instead of a single TMD. MTMD systems are arranged in two different types, serial and parallel. In this paper, a methodology that considers the structure-soil interaction (SSI) is presented for the optimum design of control systems with different configurations placed on a main structure under the influence of ground motion. To research the SSI effects, the TMDs-structure coupled system is supported by rocking and swaying springs and the corresponding dashpots, and then the equations of motions of the structural system are derived. In the optimization process based on particle swarm optimization in the frequency domain, different soil types, configuration types, and mass ratios are considered. The efficiency of optimum TMDs arranged in series and parallel is also evaluated using near and far fault ground motions in the time domain. Numerical results show that if structures are constructed on soils with low shear wave velocities, ignoring SSI can significantly change the design parameters and effectiveness of the control system.

Particle Tuned Mass Dampers for Wind-Induced Vibration Control in Supertall Building Tower Crowns

This study aims to investigate the performance of Particle Tuned Mass Damper (PTMD) in mitigating wind-induced vibrations in tower crown structures, providing findings to tower crowns with hinged boundary conditions in supertall buildings. A multi-degree-of-freedom (MDOF) model of the tower crown and a PTMD model based on the discrete element method (DEM) are established and validated. The intermediate story is a suitable choice for arranging damping devices in hinged tower crown structures. By analyzing the vibration response of the tower crown structure with PTMD under wind excitation, the study reveals the vibration mitigation effects of PTMD and the particle energy dissipation mechanism. The results indicate that the vibration reduction ratios of peak displacement and acceleration for the tower crown are 12.29% and 14.53%, respectively. Field test experiment shows its effectiveness from another perspective. Additionally, the energy dissipation between particles is the primary method of energy dissipation during collisions, accounting for approximately 80% of the total dissipated energy. Furthermore, the wide tuning frequency band characteristic of PTMD is examined through experimental testing, and its damping performance is compared with traditional Tuned Mass Damper (TMD) and Multiple Tuned Mass Damper (MTMD). Finally, the research findings, limitations, and potential impacts are discussed. This study contributes to advancing the development of tower crowns and their vibration reduction technology.

A novel casing-pipe type TMD for seismic control of free-spanning submarine pipelines: Shaking table tests and numerical simulations

Submarine pipelines are vital lifeline engineering structures for transporting offshore oil and gas resources, which may experience adverse vibrations against structural safe operation when encountering strong offshore earthquakes. This paper proposes an innovative casing-pipe type tuned mass damper (CPTMD) for the seismic control of free-spanning submarine pipelines (FSSPs). The design concept and control mechanism of the CPTMD are firstly presented. Both shaking table tests and numerical simulations are performed to examine the effectiveness of using the CPTMD to reduce seismic-induced vibration of FSSPs, through comparing structural seismic responses with and without damper device. In the experimental and numerical studies, the effect of seawater around submarine pipelines is simplified using the added hydrodynamic mass method. The experimental and numerical results consistently demonstrate that the proposed CPTMD has a good capacity for suppressing seismic-induced vibration of FSSPs. Moreover, the impacts of stiffness, damping coefficient, mass ratio and casing-pipe length on the seismic control effectiveness of the CPTMD device are investigated and discussed comprehensively, and the optimal values of these design parameters are determined. As a result, the proposed CPTMD could be an effective and simple solution for the vibration control of FSSPs induced by offshore seismic motions.

Analysis and experimental evaluation of an inertial eddy current damper for vibration control

Electromagnetic damping features non-contact operation, easy adjustability, convenient processing, and high energy consumption. Combined with the damping efficiency enhancement effect of the inertial system, it is conducive to further improving its damping effect. This paper proposes an inertial mass damper, named the Inertial Eddy Current Damper (IECD). The proposed IECD has the advantage of adjustability, meaning that the eddy current damping force can be adjusted by regulating the current in the coil. First, the mechanical model of the IECD was proposed through theoretical methods. Secondly, performance tests were conducted to verify the accuracy of the proposed mechanical model. Finally, numerical models of structures employing various applications of the IECD were established to conduct seismic response analysis. The results show that the proposed mechanical model effectively reflects the actual performance of the IECD. When used for energy dissipation and vibration reduction, the IECD demonstrates superior control performance in terms of displacement and velocity compared to the LVD, and the switch control strategy can address the issue of poor acceleration control performance. Combining the IECD with isolation bearings not only further reduces the seismic response of the superstructure but also enhances the safety of the isolation bearings, preventing excessive deformation.

Numerical Analysis of Pressure Drop and Photoresist Particle Defect Accretion in HVAC Pipe System with Dampers

The operational efficiency of HVAC (Heating, Ventilation, and Air Conditioning) systems is significantly impacted by the accumulation of particles leading to duct blockages. This research investigates the implementation of Lateral Dampers and Butterfly Dampers for airflow control, delving into the intricate mechanisms governing pressure loss within ducts due to particle deposition.Efficient HVAC operation is paramount for energy conservation and indoor air quality. The hindrance caused by particle deposition-induced blockages in ducts impedes system efficiency. This study innovates airflow control mechanisms critical for optimizing energy consumption and ensuring sustainable HVAC performance.Highlighting the novelty of this study, while prior research has explored fluid dynamics and particle deposition within ducts, the nuanced effects of damper configurations on particle deposition and pressure loss remain largely unexplored. This research addresses this gap by investigating the interplay between damper states, particle deposition, and pressure losses within HVAC duct systems.The primary objective is to unravel the relationship between damper configurations and particle accretion within HVAC ducts. Utilizing Inventor 3D modeling and Computational Fluid Dynamics (CFD) simulations employing DPM (Discrete Phase Model) and Accretion Model, the study provides insights into how damper states influence particle deposition and subsequent pressure losses. The use of the Eulerian Wall Film (EWF) model enhances the accuracy of predicting the accretion on duct and damper surfaces.Furthermore, this study extends its scope to investigate the particle information resulting from the photoresist bake process, including the generation of outgas and the principal component, benzo-pyrene. Specifically, the study examines the industrial duct's particle accretion and film formation arising from the interaction of these particles during outgas transport.Findings reveal that, for Damper 1 to 3, variations in opening ratios have negligible effects on pressure within 5 Pa, suggesting minimal influence on system performance. Notably, Butterfly Dampers demonstrate a unique behavior where any one damper reaching full closure immediately results in a pressure drop to zero. Moreover, Butterfly Damper 1 and 2 significantly impact pressure, showcasing that at a 45-degree opening, the particle deposition rate is approximately 0.5 times the rate of pressure change.The key takeaway is the development of a sophisticated algorithm for damper control, maintaining consistent pressure within ducts while optimizing airflow distribution. This algorithm has the potential to transform HVAC systems, ensuring minimal pressure loss, substantial energy savings, and heightened environmental sustainability.In summary, this paper represents a comprehensive exploration of the intricate relationships between particle deposition, pressure loss, and damper control within HVAC duct systems. By shedding light on the complex mechanisms governing these phenomena, the study contributes to the development of advanced strategies for optimizing energy efficiency in HVAC operations. Keywords: Photoresist, Particle Accretion, Film Formation, Eulerian Wall Film, Particle Deposition, CFD simulation, HVAC, Damper Control, Pressure Loss, Energy Efficiency. Figure 1

Distributed Frequency Interactive Damping Control for Multiple VSGs in Islanded Microgrids

Distributed Frequency Interactive Damping Control for Multiple VSGs in Islanded Microgrids