Tunable metamaterial beam using negative capacitor for local resonators coupling

2019 ◽  
Vol 31 (3) ◽  
pp. 389-407 ◽  
Author(s):  
Guobiao Hu ◽  
Jiawen Xu ◽  
Lihua Tang ◽  
Chunbo Lan ◽  
Raj Das
Keyword(s):  
Vibration Suppression ◽  
Element Model ◽  
Band Gaps ◽  
Analytical Models ◽  
Negative Capacitance ◽  
Multiple Band ◽  
Coupling Stiffness ◽  
Tunable Metamaterial ◽  
Circuit Technique ◽  
Shunt Circuit

This article presents a theoretical study of a tunable metamaterial beam for low-frequency broadband vibration suppression. First, the mechanism of employing the shunt circuit technique to realize the internal coupling between two adjacent local resonators is introduced. The working principle of the proposed metamaterial beam by integrating the shunt circuit technique is demonstrated. The stability of the proposed metamaterial beam is then analysed, and the corresponding criterion is proposed. Subsequently, analytical models of the proposed metamaterial beam are developed. The band structures and the transmittances are calculated. The analytical study demonstrates the generation of multiple band gaps using a shunt negative capacitance circuit, which is equivalent to a coupling spring. A parametric study is conducted to investigate the effect of the equivalent coupling stiffness on the band gaps and the corresponding suppression regions. It is found that the band gaps are controllable by varying the equivalent coupling stiffness. Finally, to verify the analytical solutions, a finite-element model of the proposed metamaterial beam is developed. The simulation results confirm the existence of multiple band gaps, which are tunable through modification of the negative capacitance. The broadband vibration-suppression ability of the proposed metamaterial beam is thus confirmed.

Application of a Negative Capacitance Circuit in Synchronized Switch Damping Techniques for Vibration Suppression

2011 ◽  
Vol 133 (4) ◽  
Author(s):  
Hongli Ji ◽  
Jinhao Qiu ◽  
Jun Cheng ◽  
Daniel Inman
Keyword(s):  
Composite Beam ◽  
Vibration Suppression ◽  
Piezoelectric Element ◽  
Single Mode ◽  
Resonant Circuit ◽  
Negative Capacitance ◽  
Control Performance ◽  
Damping Effect ◽  
Mode Control ◽  
Shunt Circuit

In the synchronized switching damping (SSD) techniques, the voltage on the piezoelectric element is switched synchronously with the vibration to be controlled using an inductive shunt circuit (SSDI). The inherent capacitance and the inductance in the shunt circuit comprise an electrically resonant circuit. In this study, a negative capacitance is used in the shunt circuit instead of an inductance in the traditional SSD technique. The voltage on the piezoelectric element can be effectively inverted although the equivalent circuit is capacitive and no resonance occurs. In order to investigate the principle of the new SSD method based on a negative capacitance (SSDNC), the variation of the voltage on the piezoelectric element and the current in the circuit are analyzed. Furthermore, the damping effect using the SSDNC is deduced, and the energy balance and stability of the new system are investigated analytically. The method is applied to the single-mode control and two-mode control of a composite beam, and its control performance was confirmed by the experimental results. For the first mode in single-mode control, the SSDNC is much more effective than SSDI. In other cases, the SSDNC is also more effective than the SSDI, although not significantly.

Research of vibration and crack propagation controls on an asymmetrical cracked rotor

2021 ◽  
pp. 107754632199822
Author(s):  
Jun Liu ◽  
Zhu Han ◽  
Rong Hu
Keyword(s):  
Crack Propagation ◽  
Vibration Suppression ◽  
Control Method ◽  
Element Model ◽  
Electromagnetic Actuator ◽  
Contact Method ◽  
Cracked Rotor ◽  
Mapping Model ◽  
Differential Control ◽  
Opening And Closing

To investigate vibration characteristics and delay crack propagations of an asymmetric cracked rotor, the 3D finite element model of the rotor system with a nonlinear contact method is established. Resonance characteristics of the asymmetrical rotor without a crack and within different locations of a crack are investigated systematically. Numerical results show that a crack affects vibration frequencies and the unstable region of the rotor. Meanwhile, an improved proportional integral differential control method with the electromagnetic actuator is used to accomplish the delay crack propagation and the vibration suppression. Based on the mapping model of opening and closing states of a crack, the effects of rotational speeds, an unbalance, and asymmetries of the rotor are discussed in detail. Experimental results show that vibrations and the breathing behavior of cracks in the rotor with the electromagnetic actuator can be suppressed, and the effectiveness of the proposed mapping model of opening and closing states of a crack is verified.

A new design of unsymmetrical shunt circuit with negative capacitance for enhanced vibration control

2021 ◽  
Vol 155 ◽  
pp. 107576
Author(s):  
Hongli Ji ◽  
Yufei Guo ◽  
Jinhao Qiu ◽  
Yipeng Wu ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Vibration Control ◽  
Negative Capacitance ◽  
Shunt Circuit

scholarly journals Structural and Acoustic Responses of a Submerged Stiffened Conical Shell

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Meixia Chen ◽  
Cong Zhang ◽  
Xiangfan Tao ◽  
Naiqi Deng
Keyword(s):  
Conical Shell ◽  
Element Model ◽  
Analytical Models ◽  
Superposition Method ◽  
Far Field ◽  
Fluid Loading ◽  
Low Frequencies ◽  
Structural Responses ◽  
The Individual ◽  
Field Sound

This paper studies the vibrational behavior and far-field sound radiation of a submerged stiffened conical shell at low frequencies. The solution for the dynamic response of the conical shell is presented in the form of a power series. A smeared approach is used to model the ring stiffeners. Fluid loading is taken into account by dividing the conical shell into narrow strips which are considered to be local cylindrical shells. The far-field sound pressure is solved by the Element Radiation Superposition Method. Excitations in two directions are considered to simulate the loading on the surface of the conical shell. These excitations are applied along the generator and normal to the surface of the conical shell. The contributions from the individual circumferential modes on the structural responses of the conical shell are studied. The effects of the external fluid loading and stiffeners are discussed. The results from the analytical models are validated by numerical results from a fully coupled finite element/boundary element model.

Experimental Characterization of a Flexible Two-Link Manipulator Arm

1993 ◽  
Author(s):  
Randall L. Mayes ◽  
G. Richard Eisler
Keyword(s):  
Element Model ◽  
Input Voltage ◽  
Analytical Models ◽  
Experimental Characterization ◽  
Frequency Range ◽  
Flexible Links ◽  
Beam Elements ◽  
Output Torque ◽  
Manipulator Arm

Abstract Experiments were performed to verify the analytical models for a robotic manipulator with two flexible links. A finite element model (FEM) employing two-dimensional beam elements was used to model the structure. A proportional model relating input voltage to output torque was used for both hub and elbow joint motors. With some minor adjustments to the link stiffness, the FEM modal frequencies matched the experimentally extracted frequencies within 1.5%. However the voltage-torque relationship for the hub motor was found to exhibit dynamics in the frequency range of interest.

Accurate Evaluation of Bolt and Clamped Members Stiffnesses Of Bolted Joints

2021 ◽  
Author(s):  
Rashique Iftekhar Rousseau ◽  
Abdel-Hakim Bouzid ◽  
Zijian Zhao
Keyword(s):  
Finite Element ◽  
Joint Stiffness ◽  
Element Model ◽  
Fe Analysis ◽  
Bolted Joints ◽  
Analytical Models ◽  
Fe Modeling ◽  
Bolted Joint ◽  
A New Technique ◽  
External Loads

Abstract The axial stiffnesses of the bolt and clamped members of bolted joints are of great importance when considering their integrity and capacity to withstand external loads and resist relaxation due to creep. There are many techniques to calculate the stiffnesses of the joint elements using finite element (FE) modeling, but most of them are based on the displacement of nodes that are selected arbitrarily; therefore, leading to inaccurate values of joint stiffness. This work suggests a new method to estimate the stiffnesses of the bolt and clamped members using FE analysis and compares the results with the FE methods developed earlier and also with the existing analytical models. A new methodology including an axisymmetric finite element model of the bolted joint is proposed in which the bolts of different sizes ranging from M6 to M36 are considered for the analysis to generalize the proposed approach. The equivalent bolt length that includes the contribution of the thickness of the bolt head and the bolt nominal diameter to the bolt stiffness is carefully investigated. An equivalent bolt length that accounts for the flexibility of the bolt head is proposed in the calculation of the bolt stiffness and a new technique to accurately determine the stiffness of clamped members are detailed.

Broadband Vibration Suppression Assessment of Negative Impedance Shunts

2008 ◽  
Author(s):  
Benjamin Beck ◽  
Kenneth A. Cunefare ◽  
Massimo Ruzzene
Keyword(s):  
Active Control ◽  
Vibration Suppression ◽  
Piezoelectric Materials ◽  
Input Power ◽  
Experimental Results ◽  
Spatial Average ◽  
Negative Capacitance ◽  
Damping Properties ◽  
Control Solution ◽  
Stiffness And Damping

Piezoelectric materials allow for the manipulation of stiffness and damping properties of host structures by the application of electrical shunting networks. The use of piezoelectric patches for broadband control of vibration using a negative impedance shunt has been shown to be an effective active control solution. The wave-tuning and minimization of reactive input power shunt selection methodologies require the use a negative capacitance. This paper shows that the two theories are comparative and obtain the same shunt parameters. The results of the theoretical shunt selection and simulation are compared to experimental results of tip vibration suppression, spatial average vibration, and reactive input power minimization.

Band Gap Control in an Active Elastic Metamaterial With Negative Capacitance Piezoelectric Shunting

2014 ◽  
Vol 136 (6) ◽  
Author(s):  
Y. Y. Chen ◽  
G. L. Huang ◽  
C. T. Sun
Keyword(s):  
Band Gap ◽  
Elastic Waves ◽  
Low Frequency ◽  
Lattice System ◽  
Band Gaps ◽  
Negative Capacitance ◽  
Bending Waves ◽  
Stiffness Constant ◽  
Elastic Metamaterials ◽  
Gap Control

Elastic metamaterials have been extensively investigated due to their significant effects on controlling propagation of elastic waves. One of the most interesting properties is the generation of band gaps, in which subwavelength elastic waves cannot propagate through. In the study, a new class of active elastic metamaterials with negative capacitance piezoelectric shunting is presented. We first investigated dispersion curves and band gap control of an active mass-in-mass lattice system. The unit cell of the mass-in-mass lattice system consists of the inner masses connected by active linear springs to represent negative capacitance piezoelectric shunting. It was demonstrated that the band gaps can be actively controlled and tuned by varying effective stiffness constant of the linear spring through appropriately selecting the value of negative capacitance. The promising application was then demonstrated in the active elastic metamaterial plate integrated with the negative capacitance shunted piezoelectric patches for band gap control of both the longitudinal and bending waves. It can be found that the location and the extent of the induced band gap of the elastic metamaterial can be effectively tuned by using shunted piezoelectric patch with different values of negative capacitance, especially for extremely low-frequency cases.

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