scholarly journals A near-field error sensing strategy for compact multi-channel active sound radiation control in free field

2019 ◽  
Vol 146 (4) ◽  
pp. 2179-2187 ◽  
Author(s):  
Jiancheng Tao ◽  
Qin Guo ◽  
Xiaojun Qiu
Keyword(s):  
Near Field ◽  
Free Field ◽  
Sound Radiation ◽  
Radiation Control

scholarly journals Effect of Soil Classification on Seismic Behavior of SMFs considering Soil-Structure Interaction and Near-Field Earthquakes

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Shahrokh Shahbazi ◽  
Iman Mansouri ◽  
Jong Wan Hu ◽  
Armin Karami
Keyword(s):  
Soil Structure ◽  
Near Field ◽  
Free Field ◽  
Soil Structure Interaction ◽  
Nonlinear Time History Analysis ◽  
Type Ii ◽  
Steel Buildings ◽  
Moment Frames ◽  
Structure Interaction ◽  
Soil Flexibility

Seismic response of a structure is affected by its dynamic properties and soil flexibility does not have an impact on it when the bottom soil of foundation is supposedly frigid, and the soil flexibility is also ignored. Hence, utilizing the results obtained through fixed-base buildings can lead to having an insecure design. Being close to the source of an earthquake production causes the majority of earthquake’s energy to reach the structure as a long-period pulse. Therefore, near-field earthquakes produce many seismic needs so that they force the structure to dissipate output energy by relatively large displacements. Hence, in this paper, the seismic response of 5- and 8-story steel buildings equipped with special moment frames (SMFs) which have been designed based on type-II and III soils (according to the seismic code of Iran-Standard 2800) has been studied. The effects of soil-structure interaction and modeling of the panel zone were considered in all of the two structures. In order to model radiation damping and prevent the reflection of outward propagating dilatational and shear waves back into the model, the vertical and horizontal Lysmer–Kuhlemeyer dashpots as seen in the figures are adopted in the free-field boundary of soil. The selected near- and far-field records were used in the nonlinear time-history analysis, and structure response was compared in both states. The results obtained from the analysis showed that the values for the shear force, displacement, column axial force, and column moment force on type-III soil are greater than the corresponding values on type-II soil; however, it cannot be discussed for drift in general.

scholarly journals Sound Radiation Control Resulting from Tire Structural Vibration

2005 ◽  
Author(s):  
Kiho Yum ◽  
Kwanwoo Hong ◽  
J. Stuart Bolton
Keyword(s):  
Sound Radiation ◽  
Structural Vibration ◽  
Radiation Control

Near-Field Ground Motion of the 2002 Denali Fault, Alaska, Earthquake Recorded at Pump Station 10

2004 ◽  
Vol 20 (3) ◽  
pp. 597-615 ◽  
Author(s):  
W. L. Ellsworth ◽  
M. Celebi ◽  
J. R. Evans ◽  
E. G. Jensen ◽  
R. Kayen ◽  
...  
Keyword(s):  
Ground Motion ◽  
Near Field ◽  
Free Field ◽  
Monitoring And Control ◽  
Peak Acceleration ◽  
Permanent Displacement ◽  
Soil Response ◽  
Denali Fault ◽  
Field Recording ◽  
Pump Station

A free-field recording of the Denali fault earthquake was obtained by the Alyeska Pipeline Service Company 3 km from the surface rupture of the Denali fault. The instrument, part of the monitoring and control system for the trans-Alaska pipeline, was located at Pump Station 10, approximately 85 km east of the epicenter. After correction for the measured instrument response, we recover a seismogram that includes a permanent displacement of 3.0 m. The recorded ground motion has relatively low peak acceleration (0.36 g) and very high peak velocity (180 cm/s). Nonlinear soil response may have reduced the peak acceleration to this 0.36 g value. Accelerations in excess of 0.1 g lasted for 10 s, with the most intense motion occurring during a 1.5-s interval when the rupture passed the site. The low acceleration and high velocity observed near the fault in this earthquake agree with observations from other recent large-magnitude earthquakes.

Free-field sound radiation measurement with multiple synchronous cameras

Measurement ◽  
2021 ◽  
pp. 110605
Author(s):  
Paolo Gardonio ◽  
Roberto Rinaldo ◽  
Loris Dal Bo ◽  
Roberto Del Sal ◽  
Emanuele Turco ◽  
...  
Keyword(s):  
Free Field ◽  
Sound Radiation ◽  
Radiation Measurement ◽  
Field Sound

Classical Electrodynamics and Acoustics: Sound Radiation by Moving Multipoles

1997 ◽  
Vol 119 (2) ◽  
pp. 271-282 ◽  
Author(s):  
G. C. Gaunaurd ◽  
T. J. Eisler
Keyword(s):  
Dirac Equation ◽  
Free Field ◽  
Sound Radiation ◽  
Equation Of Motion ◽  
Rotating Machinery ◽  
Classical Electrodynamics ◽  
Radiation Patterns ◽  
Frequency Distributions ◽  
Acoustic Sources ◽  
Power Radiation

In classical electrodynamics (CED) P. Dirac used the average of retarded and advanced fields to represent the bound field and their difference to represent the free field in his derivation of the (Lorentz-Dirac) equation of motion for an electron. The latter skew-symmetric combination filtered out the radiation part of the field. It can also be used to derive many properties of the power radiated by acoustic sources, such as angular and frequency distributions. As in CED there is radiation due to source acceleration and radiation patterns exhibit the “headlight effect.” Power radiation patterns are obtained by this approach for point multipoles undergoing various motions. Applications to sound radiation problems from rotating machinery are shown. Numerous computed plots illustrate all cases.

Optimization of Dynamic Vibration Absorbers for Suppressing Sound Radiation of Plate Structures

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Guanghe Huo ◽  
Zhaobo Chen ◽  
Yinghou Jiao ◽  
Xuezhi Zhu
Keyword(s):  
Fixed Points ◽  
Frequency Ratio ◽  
Vibration Suppression ◽  
Damping Ratio ◽  
Sound Radiation ◽  
Thin Plates ◽  
Optimal Frequency ◽  
Radiation Control ◽  
Dynamic Vibration ◽  
Analytical Expressions

Abstract Dynamic vibration absorber (DVA) is a practical tool used for sound and vibration suppression in the specific frequency band. The parameters of DVAs should be optimally tuned to obtain the best sound and vibration suppression application effects. When the DVAs are used for structural vibration reduction, DVAs’ two parameters which are the optimal frequency ratio and damping ratio have simple analytical expressions. However, the concise analytical expressions of the DVAs that are used for suppressing the structural sound radiations have not been reported. First, this paper investigates the characteristics of DVAs in suppressing sound radiation from thin plates. Second, the fixed points’ phenomenon of the sound radiations of the plate carrying DVAs is revealed. In addition, the classical fixed points’ theory is extended into the optimization process of the DVAs that are used for sound radiation control of the plate. The analytical expression of the optimal frequency ratio, as well as the damping ratio optimization method of the DVA, is simultaneously proposed. Third, the installation position of DVAs is also presented to obtain a better acoustic radiation effect. Finally, the numerical simulations are performed to verify the availability of the method. It is showed that the best sound radiation control effect could be obtained by adopting the optimization means proposed in this paper.

Sound radiation from a centrifugal blower in a free field.

1996 ◽  
Vol 99 (4) ◽  
pp. 2509-2529
Author(s):  
Shigong Su ◽  
Sean F. Wu ◽  
Morris Y. Hsi
Keyword(s):  
Free Field ◽  
Sound Radiation ◽  
Centrifugal Blower
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