Research progress of the laser vibration measurement techniques for acoustic-to-seismic coupling landmine detection

2020 ◽  
Vol 13 (0) ◽  
pp. 1-16
Author(s):  
LI Jin-hui ◽  
◽  
MA Hui ◽  
YANG Chen-ye ◽  
ZHANG Xiao-qing ◽  
...  
Keyword(s):  
Measurement Techniques ◽  
Landmine Detection ◽  
Vibration Measurement ◽  
Research Progress ◽  
Seismic Coupling

An effective fluid model for landmine detection using acoustic to seismic coupling

2004 ◽  
Vol 115 (5) ◽  
pp. 1993-2002 ◽  
Author(s):  
Doru Velea ◽  
Roger Waxler ◽  
James M. Sabatier
Keyword(s):  
Fluid Model ◽  
Landmine Detection ◽  
Seismic Coupling

Study of Oil Starvation in Journal Bearing Using Acoustic Emission and Vibration Measurement Techniques

2020 ◽  
Vol 142 (12) ◽  
Author(s):  
Surojit Poddar ◽  
N. Tandon
Keyword(s):  
Acoustic Emission ◽  
Journal Bearing ◽  
Measurement Techniques ◽  
Peak Frequency ◽  
Vibration Measurement ◽  
Frequency Range ◽  
Frequency Shifts ◽  
Deformation And Fracture ◽  
Asperity Contacts ◽  
Ae Signals

Abstract This present article evaluates the state of starvation in a journal bearing using acoustic emission (AE) and vibration measurement techniques. A journal bearing requires a constant supply of oil in an adequate amount to develop a hydrodynamic film, thick enough to separate the surfaces and avoid asperity contacts. On a microscopic level, the surface interaction under starved lubrication results in deformation and fracture of asperities. This causes a proportionate increase in AE and vibration. The AE activities resulting from asperities interaction have significant energy in the frequency range of 100–400 kHz with peak frequencies in the range of 224–283 kHz. Further, the peak frequency shifts from the higher to lower side as the asperity interaction transits from the elastic to plastic contact. This information derived from the spectral analysis of AE signals can be used to develop condition monitoring parameters to proactively control the lubrication and prevent bearing failure.

Vibration Measurement Techniques on an Industrial Gas Turbine Rotor Train

1998 ◽  
Author(s):  
Stefan S. Florjancic ◽  
Wes Franklin ◽  
Noel Lively
Keyword(s):  
Gas Turbine ◽  
Support System ◽  
Data Reduction ◽  
Dynamic Properties ◽  
Measurement Techniques ◽  
Turbine Rotor ◽  
Vibration Measurement ◽  
Analytical Models ◽  
System Parameters ◽  
Industrial Gas Turbine

The rotordynamic behavior of an industrial gas turbine rotor train was assessed on site, and the sensitivity to unbalance was quantified. An outline of the measurement procedure is given. Differential data reduction with test unbalances was undertaken to minimize the influence of measurement uncertainty. A test unbalance was installed for one run and then shifted by 180° for the consecutive run. With differential data, the effective dynamic properties of the rotor - support - system can be estimated more accurately. A rotordynamic model was used to identify the support system parameters based on measured data. For the analysis, the anisotropic, elliptical vibration orbits were decomposed into two counter-rotating circular orbits, and the support system parameters identified match the originally predicted values well. The methods of differential data reduction, rotor train mode shape presentation, elliptical orbit decomposition, and the link of measurement to analytical models with parameter definition are described. Examples from on-site measurements are included for illustration.

Accelerated Vibration Reliability Testing of Electronic Assemblies Using Sine Dwell With Resonance Tracking

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Quang T. Su ◽  
Mohammad A. Gharaibeh ◽  
Aaron J. Stewart ◽  
James M. Pitarresi ◽  
Martin K. Anselm
Keyword(s):  
Resonant Frequency ◽  
Measurement Techniques ◽  
Excitation Frequency ◽  
Building Blocks ◽  
Test Method ◽  
Circuit Board ◽  
Vibration Measurement ◽  
Fe Model ◽  
Reliability Testing ◽  
Sinusoidal Vibration

In this work, a sinusoidal vibration test method with resonance tracking is employed for reliability testing of circuit assemblies. The system continuously monitors for changes in the resonant frequency of the circuit board and adjusts the excitation frequency to match the resonant frequency. The test setup includes an electrodynamic shaker with a real-time vibration control, resistance monitoring for identifying electrical failures of interconnects, and vibration logging for monitoring changes in the dynamic response of the assembly over time. Reliability tests were performed using the resonance tracking sinusoidal test method for assemblies, each consisting of a centrally mounted ball grid array (BGA) device assembled with 63Sn37Pb and SAC105 solder alloys. These tests show that the resonance tracking method gives more consistent failure times. Failure analysis for the tested devices shows the primary failure mode is “input” trace crack first, followed by fatigue through the solder for complete failure. A finite element (FE) model, correlated with experimental modal analysis, is shown to accurately estimate the circuit board deflection estimated from the harmonic vibration data. This provides a means of estimating the stresses in the electronic interconnections while accounting for the variability between test parts. These fine-tuned vibration measurement techniques and related FE models provide the building blocks for high cycle solder fatigue plots (i.e., S–N curves).

Use of laser speckle shearing interferometric vibration measurement system for acoustic-to-seismic landmine detection

2021 ◽  
Vol 60 (08) ◽  
Author(s):  
Xiao-Qing Zhang ◽  
Chi Wang ◽  
Jin-Hui Li ◽  
Xin-Yu Luo ◽  
Chao Wang ◽  
...  
Keyword(s):  
Measurement System ◽  
Laser Speckle ◽  
Landmine Detection ◽  
Vibration Measurement

Benchmarking of deformation and vibration measurement techniques for nuclear fuel pins

Measurement ◽  
2013 ◽  
Vol 46 (9) ◽  
pp. 3647-3653 ◽  
Author(s):  
B. De Pauw ◽  
S. Vanlanduit ◽  
K. Van Tichelen ◽  
T. Geernaert ◽  
K. Chah ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Measurement Techniques ◽  
Vibration Measurement
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