scholarly journals Adaptive Torsional Tuned Vibration Absorber for Rotary Equipment

Vibration ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 116-134 ◽  
Author(s):  
Taher Abu Seer ◽  
Nader Vahdati ◽  
Oleg Shiryayev
Keyword(s):  
Natural Frequency ◽  
Degree Of Freedom ◽  
Vibration Absorber ◽  
Torsional Vibrations ◽  
Rotating System ◽  
Laboratory Test Results ◽  
Innovative Solution ◽  
Bond Graph Modeling ◽  
Rotary Equipment ◽  
Tuned Vibration Absorber

This paper proposes an innovative solution to suppress torsional vibrations in any rotating machinery with a variable frequency of excitation, or a variable natural frequency. The adaptive torsional tuned vibration absorber (ATTVA) was designed using an integrated electromagnetic circuit, which can adapt its natural frequency to match the varying natural frequency of any Multi Degree of Freedom (MDOF) rotating system. A two degree of freedom rotating system was modeled along with the integrated ATTVA using the bond graph modeling technique. Simulation results showed that torsional vibrations can be easily attenuated by controlling the capacitance shunted to the voice coil circuit. The ATTVA was designed, fabricated and evaluated on a test rig in the laboratory. Test results revealed good matching between the mathematical model and the experimental data. Experiments were performed with different configurations of the ATTVA, and the experimental results showed reasonable suppression in vibration magnitude at the desired frequency.

Adaptive Electromagnetic Torsional Tuned Vibration Absorber and its Application in Rotating Equipment

2012 ◽  
Author(s):  
Taher Abu Seer ◽  
Nader Vahdati ◽  
Hamad Karki ◽  
Oleg Shiryayev
Keyword(s):  
Natural Frequency ◽  
Torsional Vibration ◽  
Natural Frequencies ◽  
Vibration Reduction ◽  
Vibration Absorber ◽  
Torsional Vibrations ◽  
Wide Range ◽  
Simulation Results ◽  
Rotating Equipment ◽  
Tuned Vibration Absorber

Rotating equipment is susceptible to torsional vibrations whenever the RPM of the rotating equipment matches one of the torsional natural frequencies. For rotating equipment running at constant RPM, it is easy to control and mitigate the torsional vibrations, but in applications where the RPM is no longer a constant and varies widely or natural frequencies are changing: there is a need for a wide range vibration reduction device. In this paper, a translational adaptive electromagnetic tuned vibration absorber (ETVA) is described where its natural frequency is varied using electronics. The ETVA is modeled and its simulation results correlate very well with experimental results. Later, this concept is used to develop a torsional tuned vibration absorber (TTVA) device. The electromagnetic TTVA can be attached to rotating equipment to control torsional vibrations. The electromagnetic TTVA adapts itself and controls the torsional vibrations as and when the RPM varies. Here in this paper, the rotating equipment and the electromagnetic TTVA are modeled. Analysis results indicate that the torsional vibration of rotating equipment can be easily controlled using this newly developed electromagnetic TTVA.

A Robust Semi-Active Tuned Vibration Absorber for Reducing Vibrations in Force-Excited Structures

2002 ◽  
Author(s):  
Jeong-Hoi Koo ◽  
Mehdi Ahmadian ◽  
Mehdi Setareh ◽  
Thomas M. Murray
Keyword(s):  
Natural Frequency ◽  
Primary Structure ◽  
Equivalent Model ◽  
Design Parameters ◽  
Vibration Absorber ◽  
Structural Systems ◽  
Mass Ratio ◽  
Closed Form Solutions ◽  
Floor Systems ◽  
Tuned Vibration Absorber

A passive TVA is only effective when it is tuned properly; otherwise, it can magnify the vibration levels. Often, inevitable off-tuning of a TVA occurs due to changes in the primary structure mass and stiffness for force-excited structural systems such as a floor. The main purpose of this study is to evaluate the robustness of semi-active groundhook TVAs to structure mass and stiffness off-tuning. In the case of floor systems, adding external mass to an existing floor, such as people and furniture, will increase the floor mass, and reduce the mass ratio. Theses changes result in off-tuning of the frequency ratio, which is defined by the ratio of the natural frequency of the TVA to the primary structure natural frequency. In order to study the effect of off-tuning, a force-excited equivalent model of a groundhook TVA is developed and its closed-form solutions are obtained for dynamic analysis of such systems. Moreover, the optimal design parameters of both passive and groundhook equivalent semiactive TVA models are obtained based on minimization of peak transmissibility. The two optimally tuned models are compared as the primary mass and primary structure stiffness changes. The results indicate that the peak transmissibility of the groundhook TVA is lower than that of passive, implying that the groundhook TVA is more effective in reducing vibration levels. The results further indicate that the groundhook TVA is more robust to changes in primary structure mass and stiffness.

Design Development of Rotational Energy Harvesting Vibration Absorber (R-EHTVA)

2018 ◽  
Author(s):  
Francesco Infante ◽  
William Kaal ◽  
Sara Perfetto ◽  
Sven Herold
Keyword(s):  
Energy Harvesting ◽  
Optimization Method ◽  
Degree Of Freedom ◽  
Structural Vibration ◽  
Vibration Absorber ◽  
Design Development ◽  
Dynamic Vibration Absorber ◽  
Rotating System ◽  
Power Sources ◽  
Piezoelectric Energy

This paper proposes a novel idea of a combined piezoelectric energy harvesting and torsional vibration absorber for rotating system. In particular, among possible alternative solutions for durable power sources useable in mechanical components, vibration represents a suitable method for the amount of power required to feed a wireless sensor network. For this purpose energy harvesting from structural vibration has received much attention in the past few years. Suitable vibration can be found in numerous mechanical environments including automotive moving structures, household applications, but also buildings and bridges. Similarly, a dynamic vibration absorber (DVA) is one of the most used devices to mitigate the vibration structures. This device is used to transfer the primary structural vibration to the auxiliary system. Thus, vibration energy is effectively localized in the secondary less sensitive structure and it can be harvested. This paper describes the design process of an energy harvesting tuned vibration absorber for rotating system using piezoelectricity components. Instead of being dissipated as heat, the energy of vibration is converted into electricity. The device proposed is designed to mitigate torsional vibrations as a rotational vibration absorber and to harvest energy as a power source for immediate use. The initial rotational multi degree of freedom system is initially reduced in equivalent single degree of freedom (SDOF) systems. An optimization method is used for evaluating the optimal mechanical parameters of the initial absorber for the SDOF systems defined. The design is modified for the integration of the active patches without detuning the absorber. In order to estimate the real power generated, a complex storage circuit is implemented. A fixed voltage is obtained as output. Through the introduction of a big capacitor, the energy stored is measured at different frequencies. Finally, the simultaneously achievement of the vibration reduction function and the energy harvesting function is evaluated.

Control of a Tuned Vibration Absorber Based on SMA Wires

2005 ◽  
Author(s):  
Eric Williams ◽  
Mohammad H. Elahinia ◽  
Jeong-Hoi Koo
Keyword(s):  
Shape Memory ◽  
Natural Frequency ◽  
Constitutive Relations ◽  
Robustness Analysis ◽  
Vibration Absorber ◽  
Primary System ◽  
Frequency Change ◽  
Simulation Results ◽  
Close Loop Control ◽  
Tuned Vibration Absorber

This paper presents the control simulation results of a tuned vibration absorber (TVA) that utilizes the properties of shape memory alloy (SMA) wires. A conventional passive TVA is effective when it is precisely tuned to the frequency of a vibration mode; otherwise, resonance may occur that could damage the system. Additionally, in many applications the frequency of the primary system often changes over time. For example, the mass of the primary system can change causing a change in its natural frequency. This frequency change of the primary system can significantly degrade the performance of the TVA. To cope with this problem, many alternative TVA’s (such as semiactive, adaptive, and active TVA’s) have been studied. As another alternative, this paper investigates the use of Shape Memory Alloys (SMA’s) in passive TVA’s in order to improve the robustness of the TVA’s subject to mass change in the primary system. This allows for effective tuning of the stiffness of the TVA to adapt to the changes in the primary system’s natural frequency. To this end, a close-loop control system adjusts the applied current to the SMA wires in order to maintain the desired stiffness. The model, presented in this paper, contains the dynamics of the TVA along with the SMA wire model that includes phase transformation, heat transfer, and the constitutive relations. The closed-loop robustness analysis is performed for the SMA-TVA and is compared with the equivalent passive TVA. For the robustness analysis, the mass of the primary system is varied by ± 30% of its nominal mass. The simulation results show that the SMA-TVA is more robust than the equivalent passive TVA in reducing peak vibrations in the primary system subject to change of its mass.

Case Studies on the Use of Two and Three Degree of Freedom Models to Understand Fundamental Vibration Behavior of Complex Systems

2014 ◽  
Author(s):  
Ryan D. Hodge ◽  
Caner Demirdogen
Keyword(s):  
Complex System ◽  
Natural Frequency ◽  
Lessons Learned ◽  
Degree Of Freedom ◽  
Modal Testing ◽  
Vibration Absorber ◽  
Engine Component ◽  
Three Degree Of Freedom ◽  
Base Structure ◽  
Simple Models

Mathematical models of simple two and three degree of freedom vibrating systems are beneficial to ease understanding of a complex system by providing an opportunity to readily identify the effect of one degree of freedom on another. When dealing with short timelines in industry, simple models provide the opportunity to quickly develop potential solutions to excessive vibration issues or understand unexpected results. Simple models are not always appropriate and may have significant uncertainties but such an option may still add value when compared to the time and effort required to develop larger, detailed models. This paper presents two cases regarding the use of simple models to develop understanding of a complex system. In each case, the focus is on the insights that can be gained from a simple model rather than the detailed calculations and calibrations necessary to ensure its complete accuracy. Case 1 employs a two degree of freedom system to relate how an experimental modal test of an engine component can be affected by the base structure on which it is mounted. This study directly relates to the experimental modal testing of large engine components which are tested both in laboratories and on engines. Two charts are presented to evaluate the error of a measured natural frequency as a function of both the mass and natural frequency of the component to be tested and the base structure. Case 2 utilizes a three degree of freedom system built in a commercial finite element analysis (FEA) code and solved via a multi-disciplinary optimizer to determine the ideal parameters of a vibration absorber to effect the greatest possible reduction in vibration levels of a component. The lessons learned from this study are applicable to developing a vibration absorber to be installed on an engine component that is being excited by global modes of a generator set. Both cases display the significant lessons that can be learned from extremely simple systems.

Dual-mass flywheels with tuned vibration absorbers for application in heavy-duty truck powertrains

2020 ◽  
Vol 234 (10-11) ◽  
pp. 2500-2508 ◽  
Author(s):  
Lina Wramner
Keyword(s):  
Combustion Engine ◽  
Vibration Absorber ◽  
Torsional Vibrations ◽  
Vibration Absorbers ◽  
Heavy Duty ◽  
Heavy Duty Truck ◽  
Tuned Vibration Absorbers ◽  
Resonance Frequencies ◽  
Tuning Frequency ◽  
Tuned Vibration Absorber

As the heavy-duty combustion engine development goes towards lower rotational speeds and higher cylinder pressures, the torsional vibrations increase. There is therefore a need to identify and study new types of vibration absorbers that can reduce the level of torsional vibrations transmitted from the engine to the gearbox. In this work, the concept of a dual-mass flywheel combined with a tuned vibration absorber is analysed. The tuned vibration absorber efficiently reduces the vibration amplitudes for engine load frequencies near the tuning frequency, but it also introduces an additional resonance into the system. By placing the tuned vibration absorber on an intermediate flange between the two dual-mass flywheels, the introduced resonance frequency will be lower than the tuning frequency and a resonance in operating engine speed range can be avoided. Numerical simulations are used to show how the torsional vibration amplitudes in a heavy-duty truck powertrain are affected by the tuned vibration absorber and how the different parameters of the tuned vibration absorber and the dual-mass flywheel affect the torsional vibrations and the resonance frequencies.

Studies on the damping mechanism of shape memory alloy-spring tuned vibration absorber attached to a multi-degree-of-freedom structure

2021 ◽  
pp. 107754632110185
Author(s):  
Zheng Lu ◽  
Kunjie Rong ◽  
Li Tian ◽  
Canxing Qiu ◽  
Jiang Du
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Waves ◽  
Numerical Models ◽  
Degree Of Freedom ◽  
Hysteretic Behavior ◽  
System Response ◽  
Vibration Absorber ◽  
Transmission Tower ◽  
Tuned Vibration Absorber

To mitigate the adverse structural responses, an improved version of the traditional tuned vibration absorber has been proposed based on the shape memory alloy spring, referred as the shape memory alloy-spring tuned vibration absorber. The finite element numerical models of the multi-degree-of-freedom structure (e.g., transmission tower) and shape memory alloy-spring tuned vibration absorber are developed by using the commercial software ANSYS, and the nonlinear behavior of the shape memory alloy spring is validated based on a previous experimental study. The damping mechanism of the shape memory alloy-spring tuned vibration absorber attached to a multi-degree-of-freedom structure under seismic excitations is investigated, and the nonlinear hysteretic behavior of the shape memory alloy spring is also discussed. The results show that the proposed damper has a two-stage damping mechanism, and its control performance is remarkable. Because the coupled system response is sensitive to the amplitude level, the optimal configuration of the shape memory alloy-spring tuned vibration absorber can be obtained by parametric analysis. Particularly, because of the nonlinear target energy transfer and transient resonance capture mechanism, the shape memory alloy-spring tuned vibration absorber exhibits stable control ability under different seismic waves, indicating a good stability in vibration control of a multi-degree-of-freedom system.

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