Traveling-wave control of the bending wave in a beam for high quality sound radiation

2021 ◽  
Vol 263 (6) ◽  
pp. 925-928
Author(s):  
Ki-Ho Lee ◽  
Jeong-Guon Ih ◽  
Donghyun Jung
Keyword(s):  
Traveling Wave ◽  
Control Method ◽  
Wave Form ◽  
Frequency Range ◽  
Effective Frequency ◽  
Reflected Waves ◽  
Radiated Sound ◽  
Sound Spectrum ◽  
Bending Wave ◽  
Wave Control

The bending wave generated by the actuator exciting a panel can be controlled to be in the traveling wave form void the structural resonances, which deteriorates the radiated sound if the panel is used as a speaker. Although such traveling-wave control method (TCM) yields a wider effective frequency range than the modal control method, the requirement of using many actuators is the practical problem yet. If a beam is employed instead of a plate as a panel speaker, the number of actuators can be reduced despite a smaller radiating surface than a plate. This study adopts three actuators for the beam control using TCM. An actuator excites the beam in the middle position, and the two actuators near the two edges are used to suppress the reflected waves from the boundaries. The control result shows that the driving-point mobility of the primary actuator is converted into that of an infinite beam, which means that the boundaries are changed into anechoic ones and the structural resonances are eliminated. Accordingly, the beam radiates a smooth sound spectrum without sharp peaks and troughs related to the resonant responses. Effects of material and dimension in determining the effective frequency range are also explored.

scholarly journals Extending the Application of One-Terminal Fault Location Method Available in Actual Time Domain Relay

2020 ◽  
Author(s):  
Gustavo A. Cunha ◽  
Felipe V. Lopes ◽  
Tiago H. Honorato
Keyword(s):  
Transmission Lines ◽  
Time Domain ◽  
Traveling Wave ◽  
Fault Location ◽  
Reflected Waves ◽  
Location Method ◽  
Actual Time ◽  
The One

Traveling wave-based fault location has attracted more and more attention from industries worldwide. This theory allowed the implementation of functions in order to increase the reliability of the obtained fault location results. Among existing functions, the classical one-terminal method requires the detection of the wave reflected from the fault, which is still considered a challenging task. A commercial relay was released with a function able to identify these reflected waves by evaluating patterns and weighted hypotheses, identifying the wavefront most likely to be the one re ected from the fault. However, as this function is embedded into a relay, it is not possible to change the method settings. Thus, this paper presents a validation of this function which is implemented externally to the relay. Besides, its application is extended for transmission lines to which the relay can not be applied, such as huge HVDC lines.

scholarly journals Feasibility Study on the Wave-Control Method using Navigation Channel with V-Shaped Cross Section

2007 ◽  
Vol 54 ◽  
pp. 771-775
Author(s):  
Osamu KUNITA ◽  
Masatoshi YUHI ◽  
Junichi YAMAZAKI ◽  
Shinya KOTAKI ◽  
Hajime ISHIDA
Keyword(s):  
Cross Section ◽  
Feasibility Study ◽  
Control Method ◽  
Navigation Channel ◽  
Shaped Cross Section ◽  
Wave Control

The Method of Successive Decrease and the Concept of Harmonic Wave Filter in Structural Wave Control

1995 ◽  
Author(s):  
Dajun Wang ◽  
Quan Wang ◽  
A. Y. T. Leung
Keyword(s):  
Vibration Control ◽  
Structural Control ◽  
Natural Frequencies ◽  
Control Method ◽  
Harmonic Wave ◽  
Flexible Structures ◽  
Modal Control ◽  
Large Space ◽  
Wave Filter ◽  
Wave Control

Abstract Most of the available vibration control methods for flexible structures are based on the modal control method, which, however, sometimes meets with problems. For examples, the problem of spillover has not been solved adequately. And, for flexible large space structures with closely spaced natural frequencies, it is very difficult to use modal method to treat vibration control problems because the modes corresponding to closely spaced and repeated frequencies can not be computed accurately. In recent years, the method of structural wave control has been developed, but it has not been studied sufficiently. The object of this paper is an attempt to solve some of the existing problems raised due to the application of the modal control method. A wave control method — the method of successive decrease is set up at first, which is aimed at one harmonic wave. Then, a new design method in wave control is proposed, based on the above method. The problem of control spillover is analyzed and the concept of harmonic wave filter is introduced. As an example, the problem of the control of structures with closely spaced natural frequencies is treated by both the method of modal control and the method of successive decrease. The numerical results show that the method of successive decrease is more effective than the method of modal control. It proves that the method of successive decrease and the concept of harmonic wave filter is promising in solving the problems of structural control.

scholarly journals HIS-Based Semiactive Suspension Dual-Frequency-Range Switching Control to Improve Ride Comfort and Antiroll Performance

2019 ◽  
Vol 2019 ◽  
pp. 1-16
Author(s):  
Xiaojian Wu ◽  
Xiang Qiu ◽  
Bing Zhou ◽  
Juhua Huang ◽  
Tingfang Zhang
Keyword(s):  
Ride Comfort ◽  
Control Method ◽  
Excitation Frequency ◽  
Switching Control ◽  
Parameter Sensitivity ◽  
The Body ◽  
Semiactive Control ◽  
Frequency Bandwidth ◽  
Dual Frequency ◽  
Frequency Range

The parameter sensitivity analysis of a hydraulically interconnected suspension (HIS) system shows that the sensitivity of the vibration responses in the bounce and roll modes to the hydraulic parameters are complementary. A novel HIS-based semiactive control method was thereby proposed to improve ride comfort and antiroll performance. In addition, the classic sky-hook max-min damping switched strategy provides significant benefits around the body resonance, but otherwise performs similarly to, or sometimes even worse than, passive suspension. Therefore, a dual-frequency-range switching strategy, which has optimal max-min damping in both frequency ranges, was developed for improving the ride comfort in a wider frequency bandwidth. In this study, a 9-DOF HIS system dynamics model was established, and the hydraulically interconnected subsystem model was validated experimentally. Subsequently, the elastic and damping characteristics of the hydraulically interconnected subsystem, as well as the parameter sensitivity in bounce mode and roll mode, were analyzed. Next, the sensitive parameters were optimized under sinusoidal excitation at various frequencies, and a frequency-range selector used to determine the excitation frequency range and adjust the shock absorber damping was designed. Finally, simulations in the frequency domain and time domain show that the proposed HIS-based semiactive dual-frequency-range switching control suspension improves the ride comfort in a wider frequency bandwidth and enhances the antiroll performance in the transient and steady steering process.

scholarly journals Free Vibration Analysis of Circular Cylindrical Shells with Arbitrary Boundary Conditions by the Method of Reverberation-Ray Matrix

2016 ◽  
Vol 2016 ◽  
pp. 1-18 ◽  
Author(s):  
Dong Tang ◽  
Guoxun Wu ◽  
Xiongliang Yao ◽  
Chuanlong Wang
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Traveling Wave ◽  
Vibration Analysis ◽  
Cylindrical Shells ◽  
Free Vibration Analysis ◽  
Wave Form ◽  
Arbitrary Boundary ◽  
Arbitrary Boundary Conditions ◽  
Circular Cylindrical Shells

An analytical procedure for free vibration analysis of circular cylindrical shells with arbitrary boundary conditions is developed with the employment of the method of reverberation-ray matrix. Based on the Flügge thin shell theory, the equations of motion are solved and exact solutions of the traveling wave form along the axial direction and the standing wave form along the circumferential direction are obtained. With such a unidirectional traveling wave form solution, the method of reverberation-ray matrix is introduced to derive a unified and compact form of equation for natural frequencies of circular cylindrical shells with arbitrary boundary conditions. The exact frequency parameters obtained in this paper are validated by comparing with those given by other researchers. The effects of the elastic restraints on the frequency parameters are examined in detail and some novel and useful conclusions are achieved.

Hybrid Active Wave/Mode Control of Space Prestressed Taut Cable Net Structures

2018 ◽  
Vol 10 (06) ◽  
pp. 1850062 ◽  
Author(s):  
Xiao-Fei Ma ◽  
Tuan-Jie Li ◽  
Zuo-Wei Wang
Keyword(s):  
Shape Control ◽  
Large Scale ◽  
Control Method ◽  
Wave Mode ◽  
Control Model ◽  
Force Balance ◽  
Control Force ◽  
Mode Control ◽  
Active Wave ◽  
Wave Control

The space environments and special mission demands require large-scale and high shape accuracy cable net structures. The vibration control is an essential issue for shape control and performance conservation of large flexible cable net structures. This paper investigates the hybrid active wave/mode control of space prestressed taut cable net structures. First, the traveling wave dynamic model of cable net structures is explored by elemental waveguide and propagation equations of cables together with force balance conditions and compatibility conditions of joints. Then, the active wave control model is established by using the assumption forms of wave controllers to adjust the mechanical boundaries of the controlled joints. Finally, the hybrid active wave/mode control model is proposed by constructing the mapping relationship between wave control force, modal damping and natural frequencies. The proposed control method is verified by a planar cable net structure and the results show that the hybrid active wave/mode control can give a better broadband vibration attenuation performance for space prestressed taut cable net structures.

A Novel Trapezoidal Wave Control Method for a Single-Phase Grid-Tied T-Type Inverter

2021 ◽  
Vol 36 (4) ◽  
pp. 4711-4722
Author(s):  
Zhen Zhang ◽  
Junming Zhang ◽  
Shuai Shao
Keyword(s):  
Single Phase ◽  
Control Method ◽  
Wave Control

Vibroacoustic Optimization of Mechanical Structures: A Controlled Random Search Approach

2012 ◽  
Vol 622-623 ◽  
pp. 158-161 ◽  
Author(s):  
Mostafa Ranjbar ◽  
Steffen Marburg
Keyword(s):  
Random Search ◽  
Power Level ◽  
Search Method ◽  
Frequency Range ◽  
Controlled Random Search ◽  
Sound Power Level ◽  
Specific Frequency ◽  
Radiated Sound ◽  
Search Approach ◽  
Radiated Sound Power

A combination of controlled random search method and geometry modification concept is used to minimize the root mean square level of structure borne sound for a model. The structure is a rectangular plate made of steel. A specific frequency range for this porpuse is considered. The results show that this approach could produce significant reduction in the value of radiated sound power level of the structure within a limited time.

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