scholarly journals Diagnostics of concrete plate in bending with ultrasonic waves modulated by low frequency oscillations

2013 ◽  
Vol 12 (1) ◽  
pp. 243-250
Author(s):  
Błażej Meronk ◽  
Krzysztof Wilde
Keyword(s):  
Experimental Study ◽  
Low Frequency ◽  
Ultrasonic Waves ◽  
Modulation Method ◽  
Frequency Spectra ◽  
Concrete Plate ◽  
Low Frequency Oscillations ◽  
Damaged Zone ◽  
Nonlinear Acoustic ◽  
Concrete Elements

The paper presents the experimental study on the inter-modulation method for the diagnostics of concrete elements. The tests were conducted on a concrete plate subjected to ultrasonic waves and low frequency vibrations. The nonlinear acoustic effects, recorded in the experiments, made it possible to detect the presence of damaged zones. Further studies are necessary to establish the relation between the sidebanes of frequency spectra and the size of the damaged zone.

scholarly journals Ultrasonic modulated waves for diagnostics of concrete elements in bending

2014 ◽  
Vol 13 (2) ◽  
pp. 283-290
Author(s):  
Błażej Meronk ◽  
Krzysztof Wilde
Keyword(s):  
Experimental Study ◽  
Low Frequency ◽  
Ultrasonic Waves ◽  
New Method ◽  
Practical Application ◽  
Concrete Plate ◽  
Low Frequency Oscillations ◽  
Nonlinear Acoustic ◽  
Modulated Waves ◽  
Concrete Elements

The paper presents the experimental study on the diagnostics of concrete elements with the use of nonlinear acoustic effects. The tests were conducted on a concrete plate subjected to ultrasonic waves modulated with and without an additional low frequency actuator. The experimental results showed that the new method based on the direct modulation of diagnostic ultrasonic waves also provided sub-harmonic frequencies that indicated the presence of damage. The new method does not require a low frequency actuator for generation of low frequency oscillations, and therefore, is more suitable for practical application.

Analysis of Vibro-Acoustic Modulations in Nonlinear Acoustics Used for Impact Damage Detection - Numerical and Experimental Study

2013 ◽  
Vol 558 ◽  
pp. 341-348 ◽  
Author(s):  
Łukasz Pieczonka ◽  
Andrzej Klepka ◽  
Wieslaw Jerzy Staszewski ◽  
Tadeusz Uhl ◽  
Francesco Aymerich
Keyword(s):  
Experimental Study ◽  
Finite Element ◽  
Composite Plate ◽  
Natural Frequencies ◽  
Impact Damage ◽  
Low Frequency ◽  
Fe Modeling ◽  
Low Frequency Vibration ◽  
Frequency Excitation ◽  
Nonlinear Acoustic

The paper investigates experimentally the effect of low-frequency vibration on nonlinear vibro-acoustic wave modulations applied to the detection of Barely Visible Impact Damage (BVID) in a composite plate. Finite Element (FE) modeling was used in a pretest stage to identify different motion scenarios of delaminated surfaces and relate them to natural frequencies of the damaged plate. In particular the opening-closing and frictional sliding actions of the defected interfaces have been considered. Subsequently, the identified frequencies have been used for low frequency excitation in nonlinear acoustic experiments on a composite plate with impact damage.

scholarly journals NON-DESTRUCTIVE LEAK DETECTION IN GALVANIZED IRON PIPE USING NONLINEAR ACOUSTIC MODULATION METHOD

SINERGI ◽  
2018 ◽  
Vol 22 (1) ◽  
pp. 19
Author(s):  
Gigih Priyandoko
Keyword(s):  
Low Frequency ◽  
Modulation Method ◽  
Destructive Testing ◽  
Signal Features ◽  
Frequency Excitation ◽  
Nonlinear Acoustic ◽  
The Difference ◽  
Acoustic Modulation ◽  
Wide Group ◽  
Non Destructive

Non-destructive testing is a wide group of analysis techniques used in science and industry to evaluate the properties of a structure without causing damage to it. The main objective of this project is to carry out experiment to detect leakage in pipeline using nonlinear acoustic modulation method. The nonlinear acoustic modulation approach with low frequency excitation and high frequency acoustic wave is used to reveal modulations in the presence of leak. The pipe used in this experiment was galvanized iron pipe. The experiment is started with the experiment of undamaged specimen and followed by the experiment of damaged specimen with manually applied leak. The results obtained are being observed and the difference between the specimen without leak and with leak can be distinguished. The distance of the leak and the distance of the outlet detected is nearly accurate to the exact location which is leak at 4.0 m and outlet at 6.0 m. Therefore, the results demonstrate that leakage can be detected using nonlinear acoustic modulation, and proved the objective of distinguish the difference between the results of specimen without leak and with leak has succeeded. The damage detection process can be eased with the knowledge on the signal features.

scholarly journals Experimental Study of Raman Spectra of Some Aromatic Hydrocarbons

2020 ◽  
Vol 65 (4) ◽  
pp. 284
Author(s):  
B. Eshchanov ◽  
Sh. Otajonov ◽  
G. Mukhamedov ◽  
I. Doroshenko ◽  
O. Karpova ◽  
...  
Keyword(s):  
Experimental Study ◽  
Aromatic Hydrocarbons ◽  
Low Frequency ◽  
Semiempirical Method ◽  
Wide Frequency Range ◽  
Torsional Vibrations ◽  
Benzene Derivatives ◽  
Frequency Range ◽  
Frequency Spectra ◽  
Potential Barriers

The vibrational spectra of liquid aromatic hydrocarbons – bromobenzene, dioxane, toluene – are studied in a wide frequency range by means of Raman spectroscopy. The manifestation of torsional vibrations of individual groups of atoms is established from the obtained data on the low-frequency spectra. The possibility of using a semiempirical method for calculating the potential barriers of methyl and halide groups in benzene derivatives is shown.

scholarly journals PLASTIC PIPE DEFECT DETECTION USING NONLINEAR ACOUSTIC MODULATION

SINERGI ◽  
2015 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Gigih Priyandoko ◽  
Tan Siew Fun
Keyword(s):  
Defect Detection ◽  
Acoustic Waves ◽  
Crack Detection ◽  
Low Frequency ◽  
Modulation Method ◽  
Plastic Pipe ◽  
Fatigue Crack Detection ◽  
Nonlinear Acoustic ◽  
The Difference ◽  
Acoustic Modulation

This project discuss about the defect detection of plastic pipe by using nonlinear acoustic wave modulation method. Nonlinaer acoustic modulations are investigated for fatigue crack detection. It is a sensitive method for damage detection and it is based on the propagation of high frequency acoustic waves in plastic pipe with low frequency excitation. The plastic pipe is excited simultaneously with a slow amplitude modulated vibration pumping wave and a constant amplitude probing wave. The frequency of both the excitation signals coincides with the resonances of the plastic pipe. An actuator is used for frequencies generation while sensor is used for the frequencies detection. Besides that, a PVP pipe is used as the specimen as it is commonly used for the conveyance of liquid in many fields. The results obtained are being observed and the difference between uncrack specimen and cracked specimen can be distinguished.

Heart Rate Variability, Emotions, and Music

2010 ◽  
Vol 24 (2) ◽  
pp. 112-119 ◽  
Author(s):  
F. Riganello ◽  
A. Candelieri ◽  
M. Quintieri ◽  
G. Dolce
Keyword(s):  
Data Mining ◽  
Heart Rate ◽  
Heart Rate Variability ◽  
Vegetative State ◽  
Low Frequency ◽  
Emotional Reactions ◽  
Heart Beat ◽  
Healthy Controls ◽  
Frequency Spectra ◽  
Emotional Value

The purpose of the study was to identify significant changes in heart rate variability (an emerging descriptor of emotional conditions; HRV) concomitant to complex auditory stimuli with emotional value (music). In healthy controls, traumatic brain injured (TBI) patients, and subjects in the vegetative state (VS) the heart beat was continuously recorded while the subjects were passively listening to each of four music samples of different authorship. The heart rate (parametric and nonparametric) frequency spectra were computed and the spectra descriptors were processed by data-mining procedures. Data-mining sorted the nu_lf (normalized parameter unit of the spectrum low frequency range) as the significant descriptor by which the healthy controls, TBI patients, and VS subjects’ HRV responses to music could be clustered in classes matching those defined by the controls and TBI patients’ subjective reports. These findings promote the potential for HRV to reflect complex emotional stimuli and suggest that residual emotional reactions continue to occur in VS. HRV descriptors and data-mining appear applicable in brain function research in the absence of consciousness.

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