PASSIVE AND ACTIVE ISOLATION OF STRUCTURAL VIBRATION TRANSMISSION BETWEEN TWO PLATES CONNECTED BY A SET OF MOUNTS

2000 ◽  
Vol 237 (3) ◽  
pp. 483-511 ◽  
Author(s):  
P. GARDONIO ◽  
S.J. ELLIOTT
Keyword(s):  
Structural Vibration ◽  
Vibration Transmission ◽  
Active Isolation

A Study of Control Strategies for the Reduction of Structural Vibration Transmission

1999 ◽  
Vol 121 (4) ◽  
pp. 482-487 ◽  
Author(s):  
P. Gardonio ◽  
S. J. Elliott
Keyword(s):  
Kinetic Energy ◽  
Degrees Of Freedom ◽  
Control Strategies ◽  
Structural Vibration ◽  
Total Power ◽  
Vibration Transmission ◽  
Active Isolation ◽  
Axial Forces ◽  
Common Framework ◽  
Base Structure

A theoretical study of the active control of structural vibration transmission in a multiple isolator system comprising a piece of equipment mounted on a base structure via active mounts is presented. Two types of problem have been studied with a common framework: first, the active isolation of vibration transmission from the equipment to the base structure and, second, the active isolation of vibration transmission from the base structure to the equipment. Four different control strategies using the measured axial velocity or/and axial force underneath or at the top of the mounts have been investigated and compared with the effectiveness of the reference control approaches of minimizing the total power transmitted from the equipment to the flexible base structure or minimizing the total kinetic energy of the suspended rigid equipment when driven by the base structure. For the first type of isolation problem the best control is achieved when a cost function which minimizes the weighted mm of the square values of the axial velocities and axial forces is implemented. For the second isolation problem the best control performance is given by the minimization of an estimate of the kinetic energy of the suspended equipment related to the translational degrees of freedom.

scholarly journals Study on Vibration Transmission among Units in Underground Powerhouse of a Hydropower Station

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3015 ◽  
Author(s):  
Jijian Lian ◽  
Hongzhen Wang ◽  
Haijun Wang
Keyword(s):  
Low Frequency ◽  
Field Tests ◽  
Vertical Vibration ◽  
Transmission Mechanism ◽  
Structural Vibration ◽  
Hydropower Station ◽  
Fe Model ◽  
Vibration Transmission ◽  
Underground Powerhouse ◽  
Mechanical Models

Research on the safety of powerhouse in a hydropower station is mostly concentrated on the vibration of machinery structure and concrete structure within a single unit. However, few studies have been focused on the vibration transmission among units. Due to the integrity of the powerhouse and the interaction, it is necessary to study the vibration transmission mechanism of powerhouse structure among units. In this paper, field structural vibration tests are conducted in an underground powerhouse of a hydropower station on Yalong River. Additionally, the simplified mechanical models are established to explain the transmission mechanism theoretically. Moreover, a complementary finite element (FE) model is built to replicate the testing conditions for comprehensive analysis. The field tests results show that: (1) the transmission of lateral-river vibration is greater than those of longitude-river vibration and vertical vibration; (2) the vibration transmission of the vibrations that is caused by the low frequency tail fluctuation is basically equal to that of the vibrations caused by rotation of hydraulic generator. The transmission mechanism is demonstrated by the simplified mechanical models and is verified by the FE results. This study can provide guidance for further research on the vibration of underground powerhouse structure.

Use of Cepstra in Acoustical Signal Analysis

1982 ◽  
Vol 104 (2) ◽  
pp. 303-306 ◽  
Author(s):  
R. H. Lyon ◽  
A. Ordubadi
Keyword(s):  
Signal Analysis ◽  
Nonlinear Filtering ◽  
Structural Vibration ◽  
Research Directions ◽  
Vibration Transmission ◽  
Transmission Path ◽  
Source Characteristics ◽  
Cepstral Analysis ◽  
Frequency Domains ◽  
Time And Frequency Domains

Cepstral Analysis is an example of nonlinear filtering that has been applied to extracting the properties of transmission path and source characteristics in acoustics. To see why this is so, we review some of the properties of linear windowing in the time and frequency domains with a view to revealing the limitations that these methods have. We then describe the cepstrum and the conditions under which it can be helpful in separating source and path characteristics. The method is illustrated by describing some applications. Finally, research directions that may help to extend the applicability of cepstral analysis to structural vibration transmission are discussed.

Investigation on vibration transmission control of a shafting system with active orthogonal support

2021 ◽  
pp. 107754632199358
Author(s):  
Yueyue Zhu ◽  
Xiling Xie ◽  
Zhiyi Zhang
Keyword(s):  
Control Method ◽  
Acoustic Radiation ◽  
Coupled System ◽  
Structural Vibration ◽  
Local Velocity ◽  
Electromagnetic Actuators ◽  
Vibration Transmission ◽  
Hull Structure ◽  
Dynamic Forces ◽  
Vibration And Sound Radiation

A large proportion of the fluctuating propulsion forces transmit to the hull structure of an underwater vehicle through the stern support and cause structural vibration and sound radiation. To reduce the influence of the dynamic forces on the hull structure, a control method that uses an active orthogonal support is proposed. The active orthogonal support is arranged in the vertical and horizontal directions to connect the stern bearing and the hull structure and equipped with electromagnetic actuators to generate counter forces. A shaft–hull-coupled system is used to investigate the effectiveness of active orthogonal support, and numerical results indicate that the hull vibration and acoustic radiation can be significantly suppressed. The effectiveness of active orthogonal support was experimented as well. The experimental results have demonstrated that the active orthogonal support with local velocity feedback control is able to attenuate vibration transmission in the shaft–hull-coupled system.

scholarly journals Train-Induced Building Vibration and Radiated Noise by Considering Soil Properties

2020 ◽  
Vol 12 (3) ◽  
pp. 937
Author(s):  
Chao Zou ◽  
Yimin Wang ◽  
Ziyu Tao
Keyword(s):  
Soil Properties ◽  
Ground Improvement ◽  
Three Dimensional ◽  
Structural Vibration ◽  
Population Increase ◽  
Land Resource ◽  
Development Mode ◽  
Vibration Transmission ◽  
Radiated Noise ◽  
The Impact

Constructing buildings above subway tracks exploits urban-area space intensively by adopting the three-dimensional overlapping development mode, which is one of the important measures for solving the contradictions among urban population increase, land resource shortage, and environmental protection. However, the vibration generated by the frequent train operations is transmitted to the upper buildings through the track structure and ground soil, which can cause structural vibrations and radiated noise and bring physical and mental side effects to occupants within the buildings. Subway projects are often located in geologically sensitive areas, while the influences of the encountered geological problems on the generation and propagation of structural vibration and structure-radiated noise within the buildings are not yet clear. Hence, this paper presents a method of studying the train-induced vibration transmission from the ground up into the buildings and the structure-radiated noise within the building. The method consists of a train-track model, track-soil-building model, and structure-radiated noise simulation. The impact of soil properties on the building vibration and structure-radiated noise is analyzed and ground-improvement measures are proposed in order to mitigate vibration and structure-radiated noise within buildings. The results show that the interaction between soil and structure has a great impact on vibration transmission from the ground into the building. Good foundations reduce vibration transmission from ground soil up into the building and lead to a lower level of structure-radiated noise. Ground improvements increase the impedance of ground soil, thereby weakening the vibration transmission and lowering the structure-radiated noise.

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