How Geometric Misalignments can affect the Accuracy of Measurements by a Novel Configuration of Self-Tracking LDV

Dinardo, Giuseppe; Fabbiano, Laura; Vacca, Gaetano

doi:10.21014/acta_imeko.v3i4.151

Cited by 4 publications

(4 citation statements)

References 8 publications

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“…For the measurement of the wall pipe radial vibrations, a laser Doppler vibrometer (LDV) was employed. The LDV has the main advantage of non-intrusive and contactless measurements without distorting the dynamics of the structures under analysis, besides a very large bandwidth useful for investigating not well-known dynamic phenomena [17]. Each tested pipe belongs to a comprehensive hydraulic system, supplied by an electro-pump running at a fixed rotational speed.…”

Section: Measurement Methodologymentioning

confidence: 99%

Fluid flow measurements by means of vibration monitoring

Campagna

Dinardo

Fabbiano

et al. 2015

Meas. Sci. Technol.

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The achievement of accurate fluid flow measurements is fundamental whenever the control and the monitoring of certain physical quantities governing an industrial process are required. In that case, non-intrusive devices are preferable, but these are often more sophisticated and expensive than those which are more common (such as nozzles, diaphrams, Coriolis flowmeters and so on). In this paper, a novel, non-intrusive, simple and inexpensive methodology is presented to measure the fluid flow rate (in a turbulent regime) whose physical principle is based on the acquisition of transversal vibrational signals induced by the fluid itself onto the pipe walls it is flowing through. Such a principle of operation would permit the use of micro-accelerometers capable of acquiring and transmitting the signals, even by means of wireless technology, to a control room for the monitoring of the process under control. A possible application (whose feasibility will be investigated by the authors in a further study) of this introduced technology is related to the employment of a net of micro-accelerometers to be installed on pipeline networks of aqueducts. This apparatus could lead to the faster and easier detection and location of possible leaks of fluid affecting the pipeline network with more affordable costs. The authors, who have previously proven the linear dependency of the acceleration harmonics amplitude on the flow rate, here discuss an experimental analysis of this functional relation with the variation in the physical properties of the pipe in terms of its diameter and constituent material, to find the eventual limits to the practical application of the measurement methodology.

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Section: Measurement Methodologymentioning

confidence: 99%

Fluid flow measurements by means of vibration monitoring

Campagna

Dinardo

Fabbiano

et al. 2015

Meas. Sci. Technol.

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“…In particular, real-time blood velocity can be accurately measured within a sample volume (SV) in correspondence of a specified depth (adjustable by the operator) from the transducer/medium interface. In this regard, despite the lack of a shared worldwide standard on US equipment testing, performance evaluation of Doppler systems is a currently investigated issue in the scientific research field [1]- [9]. A great number of Doppler test parameters is recommended by the main medical US professional bodies, to be included in Quality Control (QC) protocols [10]- [12].…”

Section: Introductionmentioning

confidence: 99%

A preliminary study on an image analysis based method for lowest detectable signal measurements in Pulsed Wave Doppler ultrasounds

Fiori¹,

Fuiano²,

Scorza³

et al. 2021

ACTA IMEKO

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<span lang="EN-GB">Nowadays, Doppler system performance evaluation is a widespread issue because a shared worldwide standard is still awaited. Among the recommended Doppler test parameters, the lowest detectable signal could be considered mandatory in Quality Control (QC) protocols for Pulsed Wave (PW) Doppler. Such parameter is defined as the minimum signal level that can be clearly distinguished from noise and therefore, it is considered as related to PW Doppler sensitivity. The present study focuses on proposing and validating a novel image analysis based method for the estimation of the Lowest Detectable Signal in the spectrogram image (LDS<sub>IMG</sub>), namely Automatic Doppler Sensitivity Measurement Method (ADSMM), as well as to compare its results with the outcomes retrieved from the Naked Eye Doppler Sensitivity Method (NEDSM), based on the mean judgment of three independent observers. Data have been collected from a Doppler flow phantom, through three ultrasound systems for general purpose imaging, equipped with two linear array probes each and with two configuration settings. Results are globally compatible among the proposed methods, US systems and settings. Further studies could be carried out on a higher number of US diagnostic systems, Doppler frequencies and observers, as well as with different probe and phantom models.</span>

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“…The authors claimed, however, that these problems exert a negligible influence on engine-order responses of interest. Dinardo et al 18,19 evaluated the reliability of a special LDV arrangement thought to be appropriate for investigating the vibrations in rotating machine components. The evaluation was accompanied by a study of errors caused by the use of extra external optics in assessing the uncertainty of measurements.…”

Section: Introductionmentioning

confidence: 99%

Investigating the vibrational behaviour of a rotating two-blade propeller by using a self-tracking method

Ashory

Talebi

Ghadikolaei

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part C:

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This study investigated the vibrational behaviour of a rotating two-blade propeller at different rotational speeds by using self-tracking laser Doppler vibrometry. Given that a self-tracking method necessitates the accurate adjustment of test setups to reduce measurement errors, a test table with sufficient rigidity was designed and built to enable the adjustment and repair of test components. The results of the self-tracking test on the rotating propeller indicated an increase in natural frequency and a decrease in the amplitude of normalized mode shapes as rotational speed increases. To assess the test results, a numerical model created in ABAQUS was used. The model parameters were tuned in such a way that the natural frequency and associated mode shapes were in good agreement with those derived using a hammer test on a stationary propeller. The mode shapes obtained from the hammer test and the numerical (ABAQUS) modelling were compared using the modal assurance criterion. The examination indicated a strong resemblance between the hammer test results and the numerical findings. Hence, the model can be employed to determine the other mechanical properties of two-blade propellers in test scenarios.

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How Geometric Misalignments can affect the Accuracy of Measurements by a Novel Configuration of Self-Tracking LDV

Cited by 4 publications

References 8 publications

Fluid flow measurements by means of vibration monitoring

Fluid flow measurements by means of vibration monitoring

A preliminary study on an image analysis based method for lowest detectable signal measurements in Pulsed Wave Doppler ultrasounds

Investigating the vibrational behaviour of a rotating two-blade propeller by using a self-tracking method

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