Damping Structural Resonances Using Viscoelastic Shear-Damping Mechanisms: Part II—Experimental Results

1961 ◽  
Vol 83 (4) ◽  
pp. 414-424 ◽  
Author(s):  
Jerome E. Ruzicka
Keyword(s):  
Structural Design ◽  
Vibration Isolation ◽  
Level Structure ◽  
Experimental Results ◽  
Cantilever Beams ◽  
Structural Shape ◽  
Response Characteristics ◽  
Vibration Excitation ◽  
Isolation Systems ◽  
Shear Damping

This paper describes the experimental dynamic response characteristics of structural design configurations employing viscoelastic shear-damping mechanisms that have been discussed in a previous paper. Experimental results are given for cantilever beams fabricated from viscoelastic-damped sheet and structural shape members; results are also given for cantilever beams damped by use of the strip damper (an additive damping technique). The effects of shock excitation, steady-state vibration excitation, vibration excitation level, structure resonant frequency, and environmental temperature on the damping properties of the structural design configurations are demonstrated. The effects of structural damping on the performance of vibration isolation systems are determined and the significance of employing highly damped structural designs in fabrications intended for use in modern dynamic environments is discussed.

A Modular-Type Three-Axis Vibration Isolation System Using Negative Stiffness

2010 ◽  
Author(s):  
Md. Emdadul Hoque ◽  
Takeshi Mizuno ◽  
Yuji Ishino ◽  
Masaya Takasaki
Keyword(s):  
Vibration Isolation ◽  
Degree Of Freedom ◽  
Experimental Results ◽  
Negative Stiffness ◽  
Isolation System ◽  
Single Degree Of Freedom ◽  
Vibration Isolation System ◽  
Single Degree ◽  
In Series ◽  
Isolation Systems

A vibration isolation system is presented in this paper which is developed by the combination of multiple vibration isolation modules. Each module is fabricated by connecting a positive stiffness suspension in series with a negative stiffness suspension. Each vibration isolation module can be considered as a self-sufficient single-degree-of-freedom vibration isolation system. 3-DOF vibration isolation system can be developed by combining three modules. As the number of motions to be controlled and the number of actuators are equal, there is no redundancy in actuators in such vibration isolation systems. Experimental results are presented to verify the proposed concept of the development of MDOF vibration isolation system using vibration isolation modules.

Dynamics Enhancements of Advanced LIGO Multi-Stage Active Vibration Isolators and Related Control Performance Improvement

2012 ◽  
Author(s):  
Fabrice Matichard ◽  
Ken Mason ◽  
Richard Mittleman ◽  
Brian Lantz ◽  
Ben Abbott ◽  
...  
Keyword(s):  
Vibration Isolation ◽  
Experimental Results ◽  
Dynamical Response ◽  
Control Performance ◽  
Vibration Isolators ◽  
Multi Stage ◽  
Final Design ◽  
Active Vibration ◽  
And Performance ◽  
Isolation Systems

The control bandwidth and performance of active vibration isolation systems are usually directly related to the system dynamic characteristics. In this paper, we present results from a 4 years study carried out to improve the dynamical response and control performance on the two-stage isolator designed for Advanced LIGO detectors. The paper will focus on the platform’s first stage to illustrate prototyping, optimization, final design and the experimental results obtained during this program. The system concept, architecture and prototype will be presented. The factors initially limiting the prototype’s performance will be analyzed. Solutions based on sensors relocation, payload reduction, structural stiffening and passive techniques to damp the residual high frequency flexible modes will be presented. Experimental results obtained with the prototype will be compared with the system’s final version. The series of improvement obtained help not only to increase the system’s bandwidth, robustness and performance but also to simplify and speed up the control commissioning, which is very important for the Advanced LIGO project that will be using 5 of these platforms in each of its 3 detectors.

Theoretical and Experimental Investigation of Electrohydraulic Vibration Isolation Systems

1969 ◽  
Vol 91 (4) ◽  
pp. 981-990 ◽  
Author(s):  
Dale W. Schubert ◽  
Jerome E. Ruzicka
Keyword(s):  
Vibration Isolation ◽  
Broad Band ◽  
System Stability ◽  
Automatic Frequency ◽  
Hydraulic Actuator ◽  
Isolation System ◽  
Response Characteristics ◽  
Wide Range ◽  
Isolation Systems ◽  
System Configurations

This paper presents the results of an investigation of electrohydraulic vibration isolation systems that employ multiple electronic feedback signals to control the action of a hydraulic actuator in a closed-loop servocontrol system. The theoretical basis for the operation of the isolation system is discussed, including consideration of system stability. Experimental data are provided for unidirectional single-mass isolation system configurations that provide limited-band isolation, broad-band isolation, single-notch isolation, combined notch and broad-band isolation, multiple-notch isolation, and notch isolation with automatic frequency tracking. The results emphasize the unique performance characteristics of electrohydraulic isolation systems, including isolation of ultralow-frequency vibration, zero static and steady-state relative deflections, response substantially independent of the weight of the isolated body, and the ability to tailor the frequency-response characteristics to satisfy a wide range of specific requirements.

scholarly journals The transmissibility of a vibration isolation system with ball-screw inerter based on complex mass

2018 ◽  
Vol 37 (4) ◽  
pp. 1097-1108 ◽  
Author(s):  
Huabing Wen ◽  
Junhua Guo ◽  
Yang Li ◽  
Yue Liu ◽  
Kun Zhang
Keyword(s):  
Vibration Isolation ◽  
Damping Ratio ◽  
Experimental Tests ◽  
Experimental Results ◽  
Ball Screw ◽  
Type Ii ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Complex Mass ◽  
Isolation Systems

The wide application of the ball-screw inerter for vibration isolation has made it increasingly important to precisely determine the vibration transmissibility of the isolation system. In this reported work, the transmissibility of a vibration isolation system containing an inerter was predicted by using a complex mass M* in the calculations. The reported theoretical analysis showed that in the design of the type II inerter-spring-damper and inerter-rubber vibration isolation systems, the inertance-mass ratio must be less than twice the damping ratio to achieve improved vibration isolation performance when designing the system. To validate the findings, experimental tests were conducted on the type II inerter-spring-damper and inerter-rubber vibration isolation systems with ball-screw inerter. The experimental results showed that, based on M*, the transmissibility of these two systems was close to the experimental results, which illustrated the rationale for using M*. The results of this reported study will help facilitate the parameter design and performance analysis of a vibration isolation system with an inerter.

scholarly journals A Multi-Mode Broadband Vibration Energy Harvester Composed of Symmetrically Distributed U-Shaped Cantilever Beams

Micromachines ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 203
Author(s):  
Xiaohua Huang ◽  
Cheng Zhang ◽  
Keren Dai
Keyword(s):  
Energy Harvester ◽  
Low Frequency ◽  
Experimental Results ◽  
Vibration Energy ◽  
Cantilever Beams ◽  
Resonant Frequencies ◽  
Promising Alternative ◽  
Piezoelectric Energy ◽  
Straight Beam ◽  
Resonance Frequencies

Using the piezoelectric effect to harvest energy from surrounding vibrations is a promising alternative solution for powering small electronic devices such as wireless sensors and portable devices. A conventional piezoelectric energy harvester (PEH) can only efficiently collect energy within a small range around the resonance frequency. To realize broadband vibration energy harvesting, the idea of multiple-degrees-of-freedom (DOF) PEH to realize multiple resonant frequencies within a certain range has been recently proposed and some preliminary research has validated its feasibility. Therefore, this paper proposed a multi-DOF wideband PEH based on the frequency interval shortening mechanism to realize five resonance frequencies close enough to each other. The PEH consists of five tip masses, two U-shaped cantilever beams and a straight beam, and tuning of the resonance frequencies is realized by specific parameter design. The electrical characteristics of the PEH are analyzed by simulation and experiment, validating that the PEH can effectively expand the operating bandwidth and collect vibration energy in the low frequency. Experimental results show that the PEH has five low-frequency resonant frequencies, which are 13, 15, 18, 21 and 24 Hz; under the action of 0.5 g acceleration, the maximum output power is 52.2, 49.4, 61.3, 39.2 and 32.1 μW, respectively. In view of the difference between the simulation and the experimental results, this paper conducted an error analysis and revealed that the material parameters and parasitic capacitance are important factors that affect the simulation results. Based on the analysis, the simulation is improved for better agreement with experiments.

Design and analysis of a vibration isolation system with cam–roller–spring–rod mechanism

2021 ◽  
pp. 107754632110005
Author(s):  
Yonglei Zhang ◽  
Guo Wei ◽  
Hao Wen ◽  
Dongping Jin ◽  
Haiyan Hu
Keyword(s):  
Vibration Isolation ◽  
Dynamic Stiffness ◽  
Experimental Studies ◽  
Excitation Amplitude ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Stiffness Characteristic ◽  
Negative Stiffness Mechanism ◽  
Isolation Systems ◽  
Vibration Isolation Performance

The vibration isolation system using a pair of oblique springs or a spring-rod mechanism as a negative stiffness mechanism exhibits a high-static low-dynamic stiffness characteristic and a nonlinear jump phenomenon when the system damping is light and the excitation amplitude is large. It is possible to remove the jump via adjusting the end trajectories of the above springs or rods. To realize this idea, the article presents a vibration isolation system with a cam–roller–spring–rod mechanism and gives the detailed numerical and experimental studies on the effects of the above mechanism on the vibration isolation performance. The comparative studies demonstrate that the vibration isolation system proposed works well and outperforms some other vibration isolation systems.

Structural analysis of the trajectories of random processes formed in non-linear vibration isolation systems

2021 ◽  
Author(s):  
A.S. Gusev ◽  
L.V. Zinchenko ◽  
S.A. Starodubtseva
Keyword(s):  
Structural Analysis ◽  
Vibration Isolation ◽  
Fundamental Principle ◽  
Statistical Dependence ◽  
Absolute Maximum ◽  
Time Interval ◽  
Apparent Lack ◽  
The Road ◽  
Isolation Systems ◽  
Non Gaussian

When designing technical structures, the safety of their elements is a fundamental principle. This highlights the significance of the proposed solution to the structural analysis of the trajectories of non-Gaussian stationary processes. The solution aims to acquire source data for calculating the stress-strength reliability of structural elements operating under random loads. We analyze an approach that makes it possible to account for the statistical dependence between processes and their derivatives, despite the apparent lack of correlation between them. The considered approach can be utilized in the design of vibration protection of transport vehicles to calculate the probability of a shock absorber breakdown, the probability of loss of the road-wheel contact, etc. The operation reliability of such systems is defined as the probability that the absolute maximum of the process does not exceed the specified standard level during a certain time interval. The article presents the reliability calculation using structural analysis on the example of a one-dimensional stochastic system.

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