Low-frequency multi-mode vibration suppression of a metastructure beam with two-stage high-static-low-dynamic stiffness oscillators

2019 ◽  
Vol 230 (12) ◽  
pp. 4341-4356 ◽  
Author(s):  
Qichen Wu ◽  
Gangting Huang ◽  
Chong Liu ◽  
Shilin Xie ◽  
Minglong Xu
Keyword(s):  
Vibration Suppression ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Two Stage ◽  
Mode Vibration ◽  
Multi Mode

Reducing Multiple Modes of Vibration by Digital Filtering and Input Shaping

2010 ◽  
Author(s):  
Joshua Vaughan ◽  
William Singhose
Keyword(s):  
Vibration Suppression ◽  
Single Mode ◽  
Input Shaping ◽  
Notch Filters ◽  
Modes Of Vibration ◽  
Design Computation ◽  
Mode Vibration ◽  
Notch Filtering ◽  
Multi Mode ◽  
Better Than

The residual vibration of flexible systems can be reduced by properly shaping the reference command. There has been substantial evidence presented that input shaping is better than notch filtering for shaping reference commands to suppress vibration in mechanical systems. Much of this evidence is empirical comparisons between traditional filters and robust input shapers. Recently, a proof showing that notch filters are always equal to or longer in duration than an input shaper with identical single-mode vibration suppression constraints was presented. This paper expands on that previous result by extending the proof to multi-mode systems. The important ramification of this proof is that multi-mode input shapers suppress vibration more quickly than multi-mode notch filters. Ease of design, computation, and implementation are also discussed. Simulations of an industrial bridge crane demonstrate the key differences between the two methods.

A corrugated-core sandwich beam with local resonators for low-frequency broadband elastic wave attenuation

2021 ◽  
pp. 107754632110349
Author(s):  
Chenyang Xi ◽  
Xiaosong Zhu ◽  
Hui Zheng
Keyword(s):  
Vibration Suppression ◽  
Wave Attenuation ◽  
Dynamic Stiffness ◽  
Sandwich Beam ◽  
Low Frequency ◽  
Spectral Element ◽  
Experimental Investigations ◽  
High Attenuation ◽  
Low Frequency Vibration ◽  
Resonant Effect

This article attempts to enhance the low-frequency vibration suppression performance of corrugated-core sandwich beams. Multiple local resonators are introduced into the corrugated-core sandwich beam to acquire low-frequency bandgaps with broader bandwidth and higher wave attenuation capability. The governing equations for vibration analysis of the local resonator–attached corrugated-core sandwich beam are established based on the spectral element method, which incorporates the locally resonant effect by adding the dynamic stiffness term of one specific resonator to the degree of freedom that it attaches to. The bandgaps of the proposed periodic structure are further derived by imposing the Bloch boundary conditions. After validating the numerical model through finite element simulations as well as experimental investigations, the bandgaps and vibration transmissibility of the corrugated-core sandwich beam are carried out, both with and without attached local resonators. It is found that the vibration reduction capability of the corrugated-core sandwich beam is greatly enhanced, bringing two low-frequency bandgaps with high attenuation factors and wide bandwidths. Meantime, the first bandgap of resonator-free corrugated-core sandwich beam is broadened apparently. An interesting result is that the bandgap with higher frequency is split by a newly generated passband. Furthermore, parametric studies are performed, and it is found that the regulating characteristics of the bandgaps obtained through varying the attachment location of local resonators are similar to those through tuning their inherent parameters.

Vibration Control of Rotationally Periodic Structures Using Passive Piezoelectric Shunt Networks and Active Compensation

1999 ◽  
Vol 121 (3) ◽  
pp. 379-390 ◽  
Author(s):  
J. Tang ◽  
K. W. Wang
Keyword(s):  
Network Performance ◽  
Vibration Suppression ◽  
Periodic Structures ◽  
Hybrid Approach ◽  
Control Parameters ◽  
Current Feedback ◽  
Control Effort ◽  
Active Approach ◽  
Mode Vibration ◽  
Multi Mode

This paper proposes a multi-mode vibration suppression scheme for rotationally periodic structures. Identical active-passive hybrid piezoelectric networks are applied on each of the substructures, where active charge and current feedback is used together with passive piezoelectric shunts to optimize the network performance. By exploiting the rotational periodicity, a new algorithm is synthesized to analytically determine the control parameters. It is shown that this hybrid approach can suppress all the spatial harmonics, which cannot be achieved by purely passive piezoelectric shunts. It is also observed that such a configuration requires much less control effort (voltage and power) when compared to a purely active approach.

scholarly journals Using Waveguides to Model the Dynamic Stiffness of Pre-Compressed Natural Rubber Vibration Isolators

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1703
Author(s):  
Michael Coja ◽  
Leif Kari
Keyword(s):  
Natural Rubber ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Complex Problem ◽  
Wide Frequency Range ◽  
Vibration Isolators ◽  
Standard Linear Solid ◽  
Standard Linear ◽  
Frequency Magnitude ◽  
Good Agreement

A waveguide model for a pre-compressed cylindrical natural rubber vibration isolator is developed within a wide frequency range—20 to 2000 Hz—and for a wide pre-compression domain—from vanishing to the maximum in service, that is 20%. The problems of simultaneously modeling the pre-compression and frequency dependence are solved by applying a transformation of the pre-compressed isolator into a globally equivalent linearized, homogeneous, and isotropic form, thereby reducing the original, mathematically arduous, and complex problem into a vastly simpler assignment while using a straightforward waveguide approach to satisfy the boundary conditions by mode-matching. A fractional standard linear solid is applied as the visco-elastic natural rubber model while using a Mittag–Leffler function as the stress relaxation function. The dynamic stiffness is found to depend strongly on the frequency and pre-compression. The former is resulting in resonance phenomena such as peaks and troughs, while the latter exhibits a low-frequency magnitude stiffness increase in addition to peak and trough shifts with increased pre-compressions. Good agreement with nonlinear finite element results is obtained for the considered frequency and pre-compression range in contrast to the results of standard waveguide approaches.

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