Design Of Damper Research Articles

Multi-objective optimization design and multi-physics simulation analysis of a novel magnetorheological fluid-elastomer damper

Aiming at the problem of the suspension isolator not being able to adjust the damping, magnetorheological damping technology was introduced based on the traditional rubber passive suspension. A magnetorheological (MR) fluid damper was designed inside the rubber suspension and connected with the rubber structure to form a magnetorheological fluid-elastomer (MRFE) damper. The design principle of the MR damper was described. The principle prototype of the initial MRFE damper was designed, and the mechanical properties of the damper were tested through experiments. Taking the damping force, dynamic adjustable range and power as the optimization objectives, the structure of the MR damper was optimized using the non-dominated sorting genetic algorithm II (NSGA-II). The Pareto optimal solution set of MR damper parameters was obtained, and the structural parameters of the MR damper were determined based on the principle of minimum response time. A multi-physics field simulation model of the optimal damper was established to analyze the dynamic performance of the MR damper. The principle prototype of the optimal MRFE damper was obtained, and the optimal MR damper increased the damping force by 63.1% and the dynamic adjustable range by 104.9% compared with the initial MR damper, while the optimal MRFE damper increased the damping force by 9.27% and the dynamic adjustable range by 8.85% compared with the initial MRFE damper. The design results meet the requirements, and the proposed optimization method can provide a theoretical basis for the optimal design of related vibration-damping equipment.

Design and performance analysis of a vibration energy harvesting magnetorheological damper

Magnetorheological (MR) dampers have a promising application in vehicle semi-active suspension system, but the direct application of MR dampers in vehicle semi-active suspension system inevitably requires a large amount of electrical energy from the on-board battery and there will be a power failure problem. At the same time, mechanical energy is converted into heat due to the friction between the cylinder and the damper piston of the MR damper. In order to avoid excessive energy waste and realize the self-powered supply of the MR damper to a certain extent, a new vibration energy harvesting MR damper (VEHMRD) is developed in this paper. First, energy harvesting, damping force and self-powered mathematical models are established. Then, the structural parameters of the proposed VEHMRD are designed, and the multi-objective water-cycle algorithm is applied to find out the optimal parameters of the proposed MR damper. Power generation and damping performance are simulated using Comsol software. Finally, a prototype is fabricated, and the power generation, damping force, and self-power ability of the VEHMRD are also tested. The experimental results are also compared with the simulated ones. The results show that the experimental induction voltage is lower than the simulated one with an error of about 15 %. The difference between the experimental damping force and the simulated damping force is small, with an error within 6 %, and the maximum damping force is about 1800 N at an applied current of 1.75A. When the collected electric energy is rectified and supplied to the MR damper, the damping force can reach over 400 N. The developed VEHMRD has a higher vibration energy harvesting capability. When powered by an external power source, the damping performance of the proposed MR damper is good. In addition, it can provide a certain damping force even when self-powered.

Development and characterization of a magnetorheological damper with low-velocity sensitivity

Magnetorheological (MR) dampers, utilizing the unique properties of advanced materials, are extensively applied in vibration control systems. However, their performance is often compromised by the structural limitations of conventional designs. The damping force in conventional MR dampers is highly sensitive to velocity variations, primarily due to the interdependence between the piston area and the dimensions of the throttling channels, which are typically inseparable. This inherent coupling restricts the simultaneous optimization of the damping force and adjustable damping ratio, reducing the effectiveness of the magnetorheological dampers in velocity-sensitive environments. Moreover, conventional MR dampers are often characterized by complex structures and large sizes. To overcome these limitations, a novel double-rod bypass magnetorheological damper is proposed. Through the application of fluid mechanics principles and the rheological behavior of MR fluids, the velocity distribution within the throttling channel is thoroughly examined. The Bingham model is employed to establish both the velocity profile and the corresponding mechanical model, and the theoretical results align closely with experimental data, confirming the accuracy of the quasi-static model. Experimental results further demonstrate the proposed damper’s superior sensitivity to low velocities. This approach provides valuable theoretical guidance for the design of advanced MR dampers.

Improvement of Stockbridge Damper Design for Cable-Stayed Bridges

Stockbridge dampers are widely used to mitigate the vibrations of cable-stayed bridges and of many other cable-suspended or cable structures exposed to the action of pedestrians, traffic or wind load. Within the current research work, one of the most effective and likely used damper types, the Stockbridge damper, was investigated to support its design and application within the daily engineering praxis. The Stockbridge damper has a relatively simple structural layout, which ensures its modular design allows it to easily adapt the damper to cables having different dynamic properties (eigenfrequencies, mass, etc.). This paper focuses on two main research areas: (i) to understand the static and dynamic behaviour of the damper and the stay cable interaction to investigate the effectiveness of its damping; (ii) to study the sensitivity of the natural frequencies of the damper to the design parameters. The final aim of the research is to develop a simple design method that is easy to apply in engineering practice and allows the efficient adaptation of the Stockbridge damper to different cable-stayed bridges. Key findings include the recommendation to position the damper at approximately 20% of the cable length for optimal attenuation, the importance of detuning to maintain effectiveness under varying cable forces, and the observation that increasing the damper mass improves efficiency, particularly for detuned elements.

Torsional damper design for diesel engine: theory and application

Abstract Torsional vibration is the primary cause of engine crankshaft failure. Consequently, the reduction of engine vibration is of paramount importance for the enhancement of automotive safety and comfort. However, the lack of comprehensive insight into the damping mechanism of the torsional damper has impeded the effective control of engine torsional vibration. In order to gain insight into the vibration characteristics of the shaft system in an inline six-cylinder diesel engine, an analysis of the system’s behaviour during both free and forced vibration was conducted. A mathematical relationship was deduced between the dimensions, material, operational temperature and damping properties of the silicone oil damper. The objective was to determine the optimal damping and moment of inertia of the damper, with the aim of minimizing the torsional amplitude of the sixth harmonic. The results demonstrate a reduction in the six-harmonic torsional amplitude from 0.32° to 0.14° following the installation of the damper. The mean and relative deviations between the calculated and experimental results are 0.0018° and 0.83%, respectively. To facilitate the design of the silicone oil damper, a software program, Vibsim, was developed based on Visual Studio for the design and torsional vibration analysis of the silicone oil damper. This software is reliable in calculating results and is user-friendly.

Design, dynamic modeling and testing of a novel MR damper for cable-stayed climbing robots under wind loads

To increase the adaptability of bridge construction equipment in high-altitude settings, this study examines a magnetorheological (MR) damper designed for cable-stayed climbing robots. Initially, a novel damper incorporating a spring-MR fluid combination and three magnetic circuit units is developed. A robot-cable-wind coupling dynamic model is subsequently formulated via Hamilton’s principle, based on force analysis. The simulation results indicate that the damper’s maximum output force is 204.60 N, with optimal working currents of 0.2 A (Force 4) and 0.4 A (Force 7). To verify the analysis, testing is conducted using an MR damper. The results reveal an average relative error of 4.60% for the actual output damping force. When mounted on the robot, the climbing speed range, average relative error, and maximum relative error are controlled within 0.66 mm/s, 0.78% and 2.5%, respectively. This approach allows for the rapid selection of suitable working currents and markedly enhances the climbing stability of the robot.

Cyclic performance evaluation and hysteretic modelling of a brace-type damper with multi-phase energy dissipation

This paper presents an experimental investigation of a novel brace-type damper for seismic mitigation in steel truss framed structures. The damper exhibits a two-stage energy dissipation behaviour by combining friction damping and yielding of steel struts. The two-stage design allows for adaptability and adjustability to different levels of earthquake events. During low-to-medium intensity seismic events, the friction mechanism is responsible for energy dissipation. While during high-intensity events, the yielding of steel struts is activated to provide additional damping and ensure effective energy dissipation. A test programme comprising five proof-of-concept specimens was conducted to investigate the seismic performance of the damper. The test results demonstrated the anticipated two-stage energy dissipation sequence with exceptional ductility. The sliding surface pairs of stainless steel/mild steel and brass/mild steel performed more stable and predictable friction behaviour compared to surface pairs of mild steel/mild steel. To facilitate practical design of the novel dampers, theoretical hysteretic models were developed to quantify critical mechanical quantities of the damper. The adequacy of the design model was validated by comparing the test responses with the design predictions. The hysteretic model offered a quantitative framework for analysing and predicting the response of brace under cyclic loading.

Passivity Principle-Based Active Damper Design to Enhance Stability of a Voltage Source Converter for Weak Grid Scenario

Passivity Principle-Based Active Damper Design to Enhance Stability of a Voltage Source Converter for Weak Grid Scenario

Tuned mass dampers ‐ evaluation of the effect on two real footbridges

AbstractPedestrian comfort, subtle design, minimizing the number of fixed supports of the footbridge or material saving. These are the key arguments for integrating tuned mass dampers into the bridge project. The goal is to protect people and structure from vibrations and damage. The following paper presents findings from the design, production and tuning of mass dampers, their optimization possibilities and benefits for bridge engineering. The validity of damper design was verified on two footbridges in the Czech Republic and Slovakia. It concerns the footbridge over the Svitava River in Bílovice nad Svitavou and the footbridge over the high‐speed road in Banská Bystrica. Dynamic tests including measurement were carried out on both bridges before and after the installation of the dampers. The dynamic monitoring of the compliance of modal parameters was conducted using operational modal analysis (OMA). The evaluation of the dynamic tests also includes the response to pedestrian effects (comfort criteria) and the determination of the logarithmic decrement of the damping.

Design and test of a contactless damper for HTS maglev systems via electromagnetic shunt dampers

High-temperature superconducting (HTS) maglev system is promising to become the future high-speed transport due to its numerous advantages. However, the low-damping dynamic characteristics of superconductors make the system vulnerable to external disturbances, which present a significant challenge to its implementation. To enhance the vibration attenuation effect of the HTS maglev system, a non-contact damper that employs electromagnetic shunt damping (EMSD) and negative resistance is incorporated into the HTS maglev system. This study elucidates the principles of EMSD and negative resistance, and establishes the governing equations to describe the behavior of the HTS maglev model equipped with EMSD. Subsequently, the EMSD coupling coefficients are analysed via the finite element method (FEM) under varying conditions. Finally, a dedicated vibration test rig is designed and fabricated to validate the effectiveness of the proposed damper. The results demonstrate that the proposed damper, in combination with negative resistance, is capable of effectively suppressing vibration in HTS maglev systems. The maximum acceleration of the test model can be reduced by 86% compared with the original system without the damper. This work may provide valuable guidance for future practical implementations.

Optimal Design of Variable Peripheral Mass Dampers in Passive and Active Vibration Control of Tall Buildings

Optimal Design of Variable Peripheral Mass Dampers in Passive and Active Vibration Control of Tall Buildings

Development of a semi-active suspension using a compact magnetorheological damper with negative-stiffness components

Semi-active suspension with traditional magnetorheological (MR) dampers can attenuate vehicle’s vibration with less power consumption and high stability, nevertheless, it is not as effective as an active suspension. To further improve its vibration attenuation performance, this paper proposes a new MR damper with compact negative-stiffness components and analyses the effect of negative-stiffness characteristics on vibration attenuation performance. Its primary advantages include its high compactness which enables the suspension to be installed into the very limited space of real vehicles without any configuration change, and also its high effectiveness on reducing the vibrations as well as improving the vehicle stability. Upon the design of the new MR damper, a theoretical model and a mechanical model for the compact negative-stiffness component and the MR damper piston is established, respectively, to determine the suitable size of the negative-stiffness component and to optimize the parameters of the piston. Then the mechanical performance of the proposed new MRF damper is verified through an MTS machine. Finally, the new MR damper was mounted on a quarter-car system to evaluate its vibration attenuation performance under sky-hook algorithm by subjecting to different excitations. The experimental results demonstrated that the compact negative-stiffness MR damper has excellent vibration attenuation performance comparable to that of the active suspension.

A computationally efficient approach of tuned mass damper design for a nuclear cabinet based on two-step machine learning and optimization methods

Enhancing nuclear power plant (NPP) safety is demanded because of the recent beyond-design-basis earthquake near a NPP. Therefore, research on improving the seismic performance of the electrical cabinet, which ensures the safe operation of NPPs, is needed. In this paper, a tuned mass damper (TMD) is employed to control the seismic response of cabinet. To design the TMD, we employ existing design equations or perform numerical model–based optimization. However, limitations, such as inconsistencies with targeted control of the load and structure, the possibility of converging a local solution, and the high cost of numerical analysis. Therefore, this paper proposes a two-step machine learning and optimization method. Such an approach is utilized to find the optimal global design solution and reduce numerical analysis costs. Each step involves the design of experiment (DOE), response surface, and optimization. Notably, range setting in the DOE accounts for the difference between each step. In the first step, the sampling range is widened to determine the relationship between the design variables and the cabinet's response, and in the second step, the sampling range is narrowed depending on the result of the first step. Consequently, the proposed method reduced the cabinet's response by 35.4 % on average and numerical analysis cost declined by 1/3.

Design and modeling of a double rod magnetorheological grease damper

Design and modeling of a double rod magnetorheological grease damper

Design and experimental study of a stepped magnetorheological damper with power generation

Traditional vehicle suspension magnetorheological dampers have problems with low output damping force and require additional energy input to operate, to improve the performance of the vehicle suspension magnetorheological damper, in this paper, we propose and investigate a stepped magnetorheological damper structure with power generation, and conducts structural design and magnetic circuit analysis. The effects of different currents, damping gaps, coil slot positions, and coil turns on the damping performance of the stepped magnetorheological damper with power generation are numerically studied. The magnetic circuit sensitivity analysis of the power generation structure and the magnetorheological damper structure is also performed. Experiments have verified the effects of different input excitations on damping and energy-feeding performance, and the results of numerical analysis have been verified. The results show that when the excitation coil is wound for 257 turns, the magnetic circuit requirements are met. And the influence of different amplitudes, frequencies, and currents on the output damping force was studied through experiments. The results showed that the damping force would increase with the increase of single parameter values. When the amplitude was 7 mm, the frequency was 1 Hz, and the current was 2 A, the output damping force could reach 4500 N, meeting the requirements for use.

Simulation Analysis of Non-concentric Squeeze Film Damper

Squeeze film dampers are components that provide additional damping for rotating motors. In general, in order to achieve the best results of the squeeze film damper, it is necessary to appropriately increase the damping value, reduce the stiffness and set a reasonable eccentricity. In the process of designing the squeeze film damper, we can apply the rotor dynamics module of COMSOL software to model and simulate it, so as to achieve better simulation results and lay a foundation for the subsequent development and design of the product. In COMSOL software, in order to simplify the modeling of rotor components, we usually model squeeze film dampers based on the damping coefficient. The model calculates the damping coefficient for a short squeeze film damper and compares the results with the analytically calculated values. In addition, the damping coefficient depends on the position of the journal in the damper, i.e., the magnitude of the eccentricity. In this paper, by analyzing the dimensionless damping coefficient, bearing stiffness, journal displacement, and fluid load at different eccentricity, and plotting the fluid pressure distribution and the average oil film flow rate of the squeeze film damper, we can find the most suitable range of eccentricity and the damage-prone part of the damper, which can provide an important reference for the actual design of the squeeze film damper.

Self-centering dual rocking core system with viscous dampers in additional rocking sections

To mitigate the high mode effects and reduce the force requirements of the structural members in the multi-story self-centering dual rocking core (SDRC) system, this paper proposes the multiple self-centering dual rocking core system with viscous dampers in additional rocking sections (MSDRCV system). The sketch and ideal working mechanisms of the MSDRCV system are interpreted. The additional rocking sections are set to decrease the force requirements of structural members and viscous dampers are included to mitigate high mode responses of the additional rocking sections, introducing seismic performance enhancement. Comparative analyses on a 9-story MSDRCV system with viscous dampers in rocking sections, a 9-story multiple self-centering dual rocking core system without viscous dampers in rocking sections (MSDRC system) and a 9-story SDRC system were carried out. The MSDRCV and MSDRC system can realize the reduction of the force demands in structural members in contrast to the SDRC system. Nevertheless, the high mode responses caused the uncontrollable displacement concentration in the MSDRC system and hence aggravated the seismic performance under rare seismic events. The analysis results in the frequency domain confirmed that the viscous dampers in the MSDRCV system can efficiently control the high-mode responses. The effects of the design parameters of the viscous dampers on the peak responses of the MSDRCV systems were comprehensively studied via parametric analyses. The results offer guidance for the viscous dampers design.

Viscoelastic Fluid Flow Model for Hydrodynamic Behaviour of Magnetorheological Fluid in Valve and Shear Modes for a Damper System

In this present study, the flow behaviour of magnetorheological fluid in valve and shear modes for damping system is modelled and analysed. The fluid is modelled as viscoelastic fluid flowing between two parallel plates in pressure driven flow mode, and also as direct shear mode. In the work, the post-yield shear thinning or thickening behaviour of magnetorheological fluids are accounted for. The velocity and pressure distributions in the unsteady magnetorheological fluid flow between the electrodes of the damper are obtained by solving the momentum equation of the magnetorheological fluid flow using the Laplace transform method. There is an excellent agreement between the results of the present model and the results of the experimental studies. The adopted viscoelastic flow model describes that the rheological behaviour of the fluid is separated into distinct pre-yield and post-yield regimes. The fluid flow velocity, velocity gradient, and shear stresses have all been shown to be enhanced by an increase in the pressure drop. The viscosity of the fluid increases with an increase in the volume fraction of particles in the fluid, which causes the resistance of the fluid to flow to increase and thereby, reduces the fluid flow velocity. Fluid flow velocity is decreased as a result of increasing magnetic field strength. The design of clutches, rotary brakes, dampers, shock absorbers, prosthetic devices, polishing and grinding tools, etc. will all benefit greatly from the adoption of the current model.

Methodology for Design of Magnetorheological Dampers to Protect Wires of Overhead Power Lines

Methodology for Design of Magnetorheological Dampers to Protect Wires of Overhead Power Lines

Optimized design of silicone oil torsional damper for diesel generator

Abstract Due to the high cylinder pressure and high-performance requirements, the silicone oil damper of an inline six-cylinder diesel generator needs to be optimized to reduce the crankshaft stress. The centralized mass method was used to simplify the crankshaft system. A multi-body dynamic model was established, and the crankshaft stress and torsional vibration amplitude were simulated. The results show that the excessive shear stress at generator crank pin 5 is due to the resonance between the first-order intrinsic frequency of the shaft system and the 3rd harmonic torsional vibration. The shear stress was analyzed for different damper thicknesses and stiffnesses, and it was found that the shear stress at crank pin 5 was minimized when the damper thickness was 60 mm and the torsional stiffness was 250,000 N·m/rad. The torsional amplitudes at different speeds and frequencies were measured in the bench test, and the results were consistent with the calculations. The designed silicone oil torsional damper meets the requirements of the 2000-hour bench test.