Design, fabrication and vibration analysis of a lightweight head expander for a high frequency electrodynamic shaker

2019 ◽  
Vol 61 (10) ◽  
pp. 965-972 ◽  
Author(s):  
Hüseyin Dal ◽  
Murat Baklacı
Keyword(s):  
High Frequency ◽  
Vibration Analysis ◽  
Electrodynamic Shaker

A Shock Absorber Vibration Analysis - High-Frequency and Low-Frequency

1991 ◽  
Author(s):  
Kazufumi Kumagai ◽  
Toshiro Abe ◽  
John L. Bretl ◽  
Teruhiko Ishigaki ◽  
Ryugo Takgi
Keyword(s):  
High Frequency ◽  
Vibration Analysis ◽  
Shock Absorber ◽  
Low Frequency

A Novel Accelerometer Mounting Method for Sensing Performance Improvement in Acoustic Measurements From the Knee

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Goktug C. Ozmen ◽  
Mohsen Safaei ◽  
Lan Lan ◽  
Omer T. Inan
Keyword(s):  
Frequency Band ◽  
High Frequency ◽  
Low Frequency ◽  
Adhesive Tape ◽  
Spectral Centroid ◽  
Wearable Systems ◽  
Electrodynamic Shaker ◽  
3D Printed ◽  
The Mean ◽  
Sensing Performance

Abstract In this study, we propose a new mounting method to improve accelerometer sensing performance in the 50 Hz–10 kHz frequency band for knee sound measurement. The proposed method includes a thin double-sided adhesive tape for mounting and a 3D-printed custom-designed backing prototype. In our mechanical setup with an electrodynamic shaker, the measurements showed a 13 dB increase in the accelerometer's sensing performance in the 1–10 kHz frequency band when it is mounted with the craft tape under 2 N backing force applied through low-friction tape. As a proof-of-concept study, knee sounds of healthy subjects (n = 10) were recorded. When the backing force was applied, we observed statistically significant (p < 0.01) incremental changes in spectral centroid, spectral roll-off frequencies, and high-frequency (1–10 kHz) root-mean-square (RMS) acceleration, while low-frequency (50 Hz–1 kHz) RMS acceleration remained unchanged. The mean spectral centroid and spectral roll-off frequencies increased from 0.8 kHz and 4.15 kHz to 1.35 kHz and 5.9 kHz, respectively. The mean high-frequency acceleration increased from 0.45 mgRMS to 0.9 mgRMS with backing. We showed that the backing force improves the sensing performance of the accelerometer when mounted with the craft tape and the proposed backing prototype. This new method has the potential to be implemented in today's wearable systems to improve the sensing performance of accelerometers in knee sound measurements.

scholarly journals Energy Flow Boundary Element Method for Vibration Analysis of One and Two Dimension Structures

2008 ◽  
Vol 15 (1) ◽  
pp. 33-50 ◽  
Author(s):  
Ho-Won Lee ◽  
Suk-Yoon Hong ◽  
Do-Hyun Park ◽  
Hyun-Wung Kwon
Keyword(s):  
Boundary Element Method ◽  
Boundary Element ◽  
High Frequency ◽  
Energy Flow ◽  
Vibration Analysis ◽  
Thin Plates ◽  
Two Dimensional ◽  
Flow Boundary ◽  
Energy Equations ◽  
Element Method

In this paper, Energy Flow Boundary Element Method (EFBEM) was developed to predict the vibration behavior of one- and two-dimensional structures in the medium-to-high frequency ranges. Free Space Green functions used in the method were obtained from EFA energy equations. Direct and indirect EFBEMs were formulated for both one- and two-dimensional cases, and numerically applied to predict the energy density and intensity distributions of simple Euler-Bernoulli beams, single rectangular thin plates, and L-shaped thin plates vibrating in the medium-to-high frequency ranges. The results from these methods were compared with the EFA solutions to verify the EFBEM.

Research on Fault Diagnosis of Ship Stern Bearing Based on Vibration Analysis

2010 ◽  
Vol 139-141 ◽  
pp. 2354-2358
Author(s):  
Yong Jin ◽  
Lin Liu Zheng
Keyword(s):  
Fault Diagnosis ◽  
High Frequency ◽  
Vibration Analysis ◽  
Vibration Characteristics ◽  
Vibration Source ◽  
High Frequency Vibration ◽  
Rotary Machine ◽  
Vibration Data ◽  
Analysis Platform ◽  
Diagnostic Mode

The application of vibration analysis in fault diagnosis of rotary machine becomes more and more popular. Aiming at an abnormal high frequency vibration of a stern bearing, this paper proposed a method of fault diagnosis based on the analysis of vibration characteristics and the spectral analysis. From the gathered vibration data of a stern shaft bench through Pulse Vibration Analysis Platform, using the speed spectrum array to determine the characteristics of vibration source, with the analysis of vibration characteristics of the bench, it concluded that the abnormal high frequency vibration source of the stern bearing is a weak rigidity part of bench─ tacho-torque meter. The vibration data of again test after strengthening the part illustrated the validity of this diagnostic mode.

Dynamic Variational-Asymptotic Procedure for Laminated Composite Shells—Part II: High-Frequency Vibration Analysis

2008 ◽  
Vol 76 (1) ◽  
Author(s):  
Chang-Yong Lee ◽  
Dewey H. Hodges
Keyword(s):  
High Frequency ◽  
Vibration Analysis ◽  
Shell Theory ◽  
Low Frequency ◽  
Normal Displacement ◽  
Difficult Situation ◽  
Long Wavelength ◽  
First Approximation ◽  
Low Frequency Vibration ◽  
Characteristic Wavelength

Shell theories intended for low-frequency vibration analysis are frequently constructed from a generalization of the classical shell theory in which the normal displacement (to a first approximation) is constant through the thickness. Such theories are not suitable for the analysis of complicated high-frequency effects in which displacements may change rapidly along the thickness coordinate. Clearly, to derive by asymptotic methods, a shell theory suitable for high-frequency behavior requires a different set of assumptions regarding the small parameters associated with the characteristic wavelength and timescale. In Part I such assumptions were used to perform a rigorous dimensional reduction in the long-wavelength low-frequency vibration regime so as to construct an asymptotically correct energy functional to a first approximation. In Part II the derivation is extended to the long-wavelength high-frequency regime. However, for short-wavelength behavior, it becomes very difficult to represent the three-dimensional stress state exactly by any two-dimensional theory; and, at best, only a qualitative agreement can be expected. To rectify this difficult situation, a hyperbolic short-wave extrapolation is used. Unlike published shell theories for this regime, which are limited to homogeneous and isotropic shells, all the formulas derived herein are applicable to shells in which each layer is made of a monoclinic material.

Sign in / Sign up

Export Citation Format

Share Document