scholarly journals Analysis on Vibration Characteristics of Air Film Damping with Open Boundaries

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Hong Zhang ◽  
Dong-ze Cui ◽  
Ying-jie Jiao ◽  
Xi Chen
Keyword(s):  
Vibration Suppression ◽  
Laser Vibrometer ◽  
Skin Thickness ◽  
Vibration Exciter ◽  
Suppression Effect ◽  
Open Boundaries ◽  
Thin Skin ◽  
Dissipation Equation ◽  
Air Film ◽  
Made In

Air film damping (AFD) has been a research focus for the fatigue damage suppression problem of aeroengine blade decades ago; however significant progress has not been made in the past decade. In this paper, we present a theoretical model and experimental analysis about this technology. The dissipation mechanism of the AFD is established by assumption that the viscous gas inside the thin air film is Poiseuille flow and the energy dissipation equation of AFD with open boundaries is deduced and evaluated. Blade simulated testing specimens are designed. The vibration measurements are performed by RC-3000 vibration exciter and detected by applying the contactless laser vibrometer system. The theoretical results consist with the experimental results, and both show that AFD appears promising performance in vibration suppression. We also present how the structure parameters, such as installation position, air film length and thickness, and thin skin thickness, influence the vibration suppression effect.

scholarly journals The Influence of Skin Thickness on Flash Glucose Monitoring System Accuracy in Dogs with Diabetes Mellitus

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 408
Author(s):  
Francesca Del Baldo ◽  
Alessia Diana ◽  
Claudia Canton ◽  
Nikolina Linta ◽  
Roberto Chiocchetti ◽  
...  
Keyword(s):  
Monitoring System ◽  
Glucose Monitoring ◽  
Skin Thickness ◽  
Flash Glucose Monitoring ◽  
Thin Skin ◽  
Clinical Accuracy ◽  
The Mean ◽  
Group 2 ◽  
Diabetic Dogs ◽  
Flash Glucose Monitoring System

A flash glucose monitoring system (FGMS) has been validated for use in diabetic dogs. However, it is unknown whether skin thickness affects FGMS measurements. The aim of this study was to evaluate whether FGMS accuracy is affected by skin thickness. Fourteen client-owned diabetic dogs on insulin treatment were prospectively enrolled in the study. The dogs were divided into two groups according to their ultrasound-measured skin thickness: dogs with skin thickness < 5 mm (Group 1) and dogs with skin thickness > 5 mm (Group 2). On days 1, 7 and 14, glucose curves were obtained simultaneously using the FGMS and a validated portable blood glucose meter. Paired measurements were used to calculate the mean bias and to determine accuracy according to ISO 15197:2013 criteria. The mean bias was significantly inversely correlated (p = 0.02; r = −0.6) with the mean skin thickness. Clinical accuracy was observed only in Group 2, with 99% of the results in zone A + B of the Parkes consensus error grid analysis. In conclusion, skin thickness seems to affect FGMS measurements, and the device is accurate in dogs with thicker skin (>5 mm); in dogs with thin skin (<5 mm), the clinical accuracy is low, and the results should be interpreted with caution.

The Influence of Variable-Speed Waveforms on Vibration Suppression in Time-Varying Speed Cutting

2013 ◽  
Vol 690-693 ◽  
pp. 2514-2518
Author(s):  
Juan Cong ◽  
Yun Wang ◽  
Wei Na Yu
Keyword(s):  
Wave Speed ◽  
Vibration Suppression ◽  
Sine Wave ◽  
Time Varying ◽  
Variable Speed ◽  
Suppression Effect ◽  
Speed Variation ◽  
Input And Output ◽  
System Input ◽  
Better Than

Through the research on the change of system input and output energy in time-varying speed cutting, the influence of variable-speed waveforms on vibration suppression effect in time-varying speed cutting is quantitatively analyzed in this paper. A conclusion can be drawn that sine wave speed variation is better than triangle wave speed variation in vibration suppression.

The Fairing Arrangement for Vortex Induced Vibration Suppression Effect in Soliton Current

2020 ◽  
Vol 103 (sp1) ◽  
pp. 293
Author(s):  
Xiaoliang Qi ◽  
Dagang Zhang ◽  
Haiyan Guo ◽  
Youxiao Chen
Keyword(s):  
Vibration Suppression ◽  
Vortex Induced Vibration ◽  
Suppression Effect

Vibration suppression effect in a maglev system for flexible steel plate with curvature

2019 ◽  
Vol 59 (3) ◽  
pp. 993-1001
Author(s):  
Makoto Tada ◽  
Hikaru Yonezawa ◽  
Hiroki Marumori ◽  
Takayoshi Narita ◽  
Hideaki Kato ◽  
...  
Keyword(s):  
Steel Plate ◽  
Vibration Suppression ◽  
Suppression Effect ◽  
Maglev System

VIBRATION SUPPRESSION USING A LASER VIBROMETER AND PIEZOCERAMIC PATCHES

2000 ◽  
Vol 235 (2) ◽  
pp. 261-280 ◽  
Author(s):  
A. GHOSHAL ◽  
E.A. WHEATER ◽  
C.R. ASHOK KUMAR ◽  
M.J. SUNDARESAN ◽  
M.J. SCHULZ ◽  
...  
Keyword(s):  
Vibration Suppression ◽  
Laser Vibrometer

scholarly journals Numerical and Experimental Study on Suppression Effect of Acoustic Black Hole on Vibration Transmission of Refrigerator Compressor

2021 ◽  
Vol 11 (18) ◽  
pp. 8622
Author(s):  
Xiaofei Du ◽  
Qidi Fu ◽  
Jianrun Zhang ◽  
Chaoyong Zong
Keyword(s):  
Numerical Simulation ◽  
Black Hole ◽  
Vibration Suppression ◽  
Structural Vibration ◽  
Flexural Wave ◽  
Response Analysis ◽  
Flexural Waves ◽  
Suppression Effect ◽  
Support Plate ◽  
The Time Domain

The acoustic black hole (ABH) structures have the potential to achieve structural vibration suppression and noise reduction through the effect of the ABH on the concentration and manipulation of flexural waves. In this paper, a new solution is proposed to embed 2-D ABHs on the support plate to suppress the transmission of compressor vibration to the refrigerator body. The vibration and acoustic measurement experiment of the compressor, the support plate and the refrigerator body, and the coherence analysis of the vibration signals and acoustic signal are carried out to determine the influence of the compressor vibration on the vibration of the refrigerator body and the radiation sound of the back wall. The concentration and manipulation effects of 2-D ABH on flexural waves are verified by numerical simulation of flexural wave propagation in the time domain. FEM models of the original support plate and the damping ABH support plate are established to investigate the comprehensive effect of the 2-D ABHs and the damping layers on the vibration characteristics of the support plate through vibration modal and dynamic response analysis. Numerical simulation results show that the 2-D damping ABHs can suppress the vibrations generated by the compressor at specific frequencies in the middle and high-frequency bands from being transmitted to the refrigerator body through the support plate.

scholarly journals Numerical Investigation on Vortex-Induced Vibration Suppression of a Circular Cylinder with Axial-Slats

2019 ◽  
Vol 7 (12) ◽  
pp. 454 ◽  
Author(s):  
Wei Wang ◽  
Zhaoyong Mao ◽  
Wenlong Tian ◽  
Tingying Zhang
Keyword(s):  
Circular Cylinder ◽  
Frequency Ratio ◽  
Vibration Suppression ◽  
Amplitude Ratio ◽  
Number Range ◽  
Vortex Induced Vibration ◽  
Suppression Effect ◽  
Coverage Ratio ◽  
Region I ◽  
Region Ii

The vortex-induced vibration (VIV) suppression of a circular cylinder with the axial-slats is numerically investigated using the computational fluid dynamics (CFD) method for Reynolds number range of 8.0 × 103–5.6 × 104. The two-dimensional unsteady Reynolds averaged Navier–Stokes (RANS) equations and Shear-Stress-Transport (SST) turbulence model are used to calculate the flow around the cylinder in ANSYS Fluent. The Newmark-β method is used to evaluate structural dynamics. The amplitude response, frequency response and vortex pattern are discussed. The suppression effect of the axial-slats is the best when the gap ratio is 0.10 and the coverage ratio is 30%. Based on the VIV response, the whole VIV response region is divided into four regions (Region I, Region II, Region III and Region IV). The frequency ratio of isolated cylinder jumps between region II and region III. However, the frequency ratio jumps between region I and region II for a cylinder with the axial-slats. The axial-slats destroy the original vortex and make the vortex easier to separate. The online amplitude ratio is almost completely suppressed, and the cross-flow amplitude ratio is significantly suppressed.

Control on Dynamic Response of Fluid-Driven Deployable Mechanism by Application of Magnetorheological Elastomeric Materials

2011 ◽  
Vol 183-185 ◽  
pp. 2313-2317 ◽  
Author(s):  
Shi Rong Guo ◽  
Ling Yu Sun ◽  
Wei Wei Chen
Keyword(s):  
Vibration Suppression ◽  
Variable Magnetic Field ◽  
Nonlinear Material ◽  
Original Design ◽  
Dynamic Impact ◽  
Suppression Effect ◽  
Wide Range ◽  
Elastomeric Materials ◽  
Deployable Mechanism ◽  
Rotating Plate

A kind of intelligent materials named magnetorheological elastomers (MREs) is applied on the surface of a rotating plate to avoid resonance vibration and to attenuate the vibration amplitude. Under a variable magnetic field, the stiffness of structure with MREs can be changed in wide range. First, the field-induced shear modulus is numerically studied and compared with the experimental results. Then, other equivalent parameters in nonlinear material equation of MREs are determined. Finally, the vibration suppression effect is verified through numerical simulation of the dynamic impact response of rotating plate in a fluid-driven deployable mechanism subjected to impact loads. On the condition that the weight of the plate is fixed, its vibration response is suppressed in shorter time than original design.

The research of the operating mode of the concrete mixture plane depth compactor with a circular vibration exciter

2019 ◽  
Vol 1 (52) ◽  
pp. 5-12 ◽  
Author(s):  
Alexander Maslov ◽  
Janar Batsaikhan
Keyword(s):  
Vertical Plate ◽  
Operating Mode ◽  
Concrete Mixture ◽  
Vibration Exciter ◽  
Torsional Vibrations ◽  
Plate Movement ◽  
Concrete Mixtures ◽  
Linear Vibrations ◽  
Design Diagram ◽  
Made In

The paper proposes an essentially new design of a concrete mixture depth compactor made in the form of a vertical plate witha circular vibration exciter mounted on its upper part. A design diagram of the «plane depth compactor – concrete mixture»dynamic system is presented and the vertical plate movement equations describing its linear vibrations in the horizontal planeand torsional vibrations in relation to the center of gravity are provided. It has been determined the regularity of the verticalplate motion during the compaction of concrete mixtures. The provided results of the research enable the substantiation of therational parameters of the plane depth compactor performing spatial vibrations and the efficient modes of the vibratory actionon the concrete mixtures of different consistence.

Sign in / Sign up

Export Citation Format

Share Document