Realization of Resonance of a Diaphragm at Any Desired Frequency

2015 ◽  
Vol 34 (1) ◽  
pp. 29-34
Author(s):  
Y. Zhang ◽  
L. Huang
Keyword(s):  
Mechanical Property ◽  
Resonance Frequency ◽  
Vibration Control ◽  
Mechanical System ◽  
Electromechanical Coupling ◽  
Mass System ◽  
Low Frequencies ◽  
Control Applications ◽  
Noise And Vibration ◽  
Lc Circuit

AbstractIn noise control, the reactance of a mechanical system needs to be minimized while the resistance is chosen suitably. This work illustrates the possibility of and the ease at which such design tasks may be accomplished by utilizing strong electromechanical coupling. Moving-coil loudspeaker is chosen as the vehicle of illustration and it is considered as a simple spring-mass system when operated below its first diaphragm mode. It is shown that the system mechanical property may be tuned easily by a simple R-LC circuit. In addition to the assigned resonance frequency, there can be a maximum of two other resonances. It is argued that the ability to tune the system mechanical resonance to any frequency, such as the ones at very low frequencies, can be very useful for noise and vibration control applications.

Optimum tuning of a vibration neutralizer for global vibration control

2001 ◽  
Vol 215 (8) ◽  
pp. 933-942 ◽  
Author(s):  
J Dayou ◽  
M. J. Brennan
Keyword(s):  
Resonance Frequency ◽  
Vibration Control ◽  
Dynamic Stiffness ◽  
Control Device ◽  
Single Frequency ◽  
Active Device ◽  
Low Frequencies ◽  
Quadratic Minimization ◽  
Minimization Technique ◽  
Insight Into

This paper is concerned with optimization of the natural frequency of a vibration neutralizer to minimize the global vibration of a structure at a single frequency. The optimization is carried out using a quadratic minimization technique to determine the dynamic stiffness of the control device that is required, and then the optimum resonance frequency of the neutralizer is determined. It is shown that, with the exception of very low frequencies, an optimally adjusted vibration neutralizer can be as effective as an active device at a single frequency. Simulations are presented with a single neutralizer on a beam to facilitate insight into the mechanisms of control.

scholarly journals Design and Analysis of a Novel Piezoceramic Stack-based Smart Aggregate

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6438
Author(s):  
Guangtao Lu ◽  
Xin Zhu ◽  
Tao Wang ◽  
Zhiqiang Hao ◽  
Bohai Tan
Keyword(s):  
Resonance Frequency ◽  
Electromechanical Coupling ◽  
Structural Parameters ◽  
Electromechanical Coupling Factor ◽  
Coupling Factor ◽  
Stress Waves ◽  
Parallel Connection ◽  
Smart Aggregate ◽  
In Series ◽  
Piezoelectric Wafers

A novel piezoceramic stack-based smart aggregate (PiSSA) with piezoceramic wafers in series or parallel connection is developed to increase the efficiency and output performance over the conventional smart aggregate with only one piezoelectric patch. Due to the improvement, PiSSA is suitable for situations where the stress waves easily attenuate. In PiSSA, the piezoelectric wafers are electrically connected in series or parallel, and three types of piezoelectric wafers with different electrode patterns are designed for easy connection. Based on the theory of piezo-elasticity, a simplified one-dimensional model is derived to study the electromechanical, transmitting and sensing performance of PiSSAs with the wafers in series and parallel connection, and the model was verified by experiments. The theoretical results reveal that the first resonance frequency of PiSSAs in series and parallel decreases as the number or thickness of the PZT wafers increases, and the first electromechanical coupling factor increases firstly and then decrease gradually as the number or thickness increases. The results also show that both the first resonance frequency and the first electromechanical coupling factor of PiSSA in series and parallel change no more than 0.87% as the Young’s modulus of the epoxy increases from 0.5 to 1.5 times 3.2 GPa, which is helpful for the fabrication of PiSSAs. In addition, the displacement output of PiSSAs in parallel is about 2.18–22.49 times that in series at 1–50 kHz, while the voltage output of PiSSAs in parallel is much less than that in parallel, which indicates that PiSSA in parallel is much more suitable for working as an actuator to excite stress waves and PiSSA in series is suitable for working as a sensor to detect the waves. All the results demonstrate that the connecting type, number and thickness of the PZT wafers should be carefully selected to increase the efficiency and output of PiSSA actuators and sensors. This study contributes to providing a method to investigate the characteristics and optimize the structural parameters of the proposed PiSSAs.

Active Rejection of Harmonic Disturbances with Nonstationary Harmonically Related Frequencies Using Varying-Sampling-Time LPV Control

2016 ◽  
Vol 248 ◽  
pp. 19-26
Author(s):  
Xin Yu Shu ◽  
Pablo Ballesteros ◽  
Christian Bohn
Keyword(s):  
Vibration Control ◽  
Fundamental Frequency ◽  
Sampling Time ◽  
Linear Parameter ◽  
Linear Parameter Varying ◽  
Noise And Vibration ◽  
Active Noise ◽  
Lpv Control ◽  
Parameter Varying ◽  
Time Linear

This paper presents a method for the active noise and vibration control (ANC/AVC) of harmonically related nonstationary disturbances using varying-sampling-time linear parameter-varying (LPV) controller. The frequencies are assumed to be known and varying within given ranges and they are multiples of one fundamental frequency.

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