Experimental Configuration to Determine the Nonlinear Parameter β in PMMA and CFRP with the Finite Amplitude Method
1
Department of Structural Mechanics, University of Granada, 18071 Granada, Spain
2
Instituto de Investigación Biosanitaria, ibs.GRANADA, 18012 Granada, Spain
3
Excellence Research Unit, “Modelling Nature” (MNat), University of Granada, 18071 Granada, Spain
*
Author to whom correspondence should be addressed.
Sensors 2019, 19(5), 1156; https://doi.org/10.3390/s19051156
Received: 28 December 2018
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Revised: 15 February 2019
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Accepted: 28 February 2019
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Published: 7 March 2019
(This article belongs to the Special Issue Ultrasonic Sensors 2018)
Parameters to measure nonlinearity in polymethylmethacrylate (PMMA) and carbon fiber reinforced polymer (CFRP) materials have been determined with nonlinear ultrasound (NLUS). The nonlinear parameter has been determined using the variation of the Finite Amplitude Method (FAM) with harmonic generation. Using this as a reference, the first contribution of this work consists of deducting the experimental configuration necessary to measure this nonlinear parameter in a correct and feasible way. Excitation level, frequency of the wave generated, number of cycles analysed and the distances transducer-specimen and specimen-hydrophone have been determined in both materials. The second contribution is a semi-analytical model that allows to obtain the nonlinear parameter in materials by removing water contribution and considering geometric and viscous attenuation, using the data obtained in an immersion tank. Finally, an application of this model has been carried out in PMMA in order to determinate the nonlinear parameter in this material. From the results, we confirm that the configuration determined in this paper to obtain the parameter decreases the noise in the measurements.
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Keywords:
nonlinear parameter β; finite amplitude method; harmonic generation; polymethylmethacrylate; carbon fiber reinforced polymer
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MDPI and ACS Style
Callejas, A.; Rus, G. Experimental Configuration to Determine the Nonlinear Parameter β in PMMA and CFRP with the Finite Amplitude Method. Sensors 2019, 19, 1156. https://doi.org/10.3390/s19051156
AMA Style
Callejas A, Rus G. Experimental Configuration to Determine the Nonlinear Parameter β in PMMA and CFRP with the Finite Amplitude Method. Sensors. 2019; 19(5):1156. https://doi.org/10.3390/s19051156
Chicago/Turabian StyleCallejas, Antonio, and Guillermo Rus. 2019. "Experimental Configuration to Determine the Nonlinear Parameter β in PMMA and CFRP with the Finite Amplitude Method" Sensors 19, no. 5: 1156. https://doi.org/10.3390/s19051156
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