LASER-ULTRASONIC METHOD OF ACOUSTIC IMPEDANCE MEASUREMENT FOR QUANTITATIVE POROSITY ESTIMATION OF CROSS-PLY CARBON FIBER REINFORCED PLASTIC MATERIALS

2020 ◽  
pp. 56-63
Author(s):  
Yu. G. Sokolovskaya ◽  
N. B. Podymova ◽  
A. A. Karabutov
Keyword(s):  
Carbon Fiber ◽  
Acoustic Impedance ◽  
Acoustic Waves ◽  
Composite Structures ◽  
Ultrasonic Method ◽  
Impedance Measurement ◽  
Ultrasonic Pulse ◽  
Laser Ultrasonic ◽  
Plastic Materials ◽  
Local Porosity

A method of measuring the acoustic impedance of carbon fiber plastics based on the laser optoacoustic effect is proposed and experimentally realized. Measurement of the acoustic impedance of the studied composite is made by the value of the antiderivative of ultrasonic pulse reflected from the interface between the immersion liquid and the sample. A method for determining the porosity of a material by the measured value of the acoustic impedance, based on the dependence of the material density and the velocity of propagation of longitudinal acoustic waves in it on its porosity, is presented. Porous samples of crossply reinforced carbon plastics with three types of carbon fiber lay-up schemes were studied. It was found that the studied carbon fiber plastics have a non-uniform distribution of local porosity in the plane of carbon fabric stacking. It is also shown that the variation of the local porosity in the sample depends on the fiber laying scheme. It is shown that the porosity value obtained by X-ray computed tomography coincides with the results of laser-ultrasonic measurements. The advantage of the proposed method is the possibility of rapid diagnosis of porosity with one-way access to the object under study without measuring its dimensions and mass, which can be used for composite structures of complex shape.

Non-Destructive Testing of Thermoplastic Carbon Composite Structures

2020 ◽  
Vol 2020 (1) ◽  
pp. 34-52
Author(s):  
Rafał Szymański
Keyword(s):  
Composite Structures ◽  
Ultrasonic Method ◽  
Composite Panel ◽  
Aviation Industry ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulse Technique ◽  
Thermoplastic Matrix ◽  
The Subject ◽  
Non Destructive

AbstractThe article is in line with the contemporary interests of companies from the aviation industry. It describes thermoplastic material and inspection techniques used in leading aviation companies. The subject matter of non-destructive testing currently used in aircraft inspections of composite structures is approximated and each of the methods used is briefly described. The characteristics of carbon preimpregnates in thermoplastic matrix are also presented, as well as types of thermoplastic materials and examples of their application in surface ship construction. The advantages, disadvantages and limitations for these materials are listed. The focus was put on the explanation of the ultrasonic method, which is the most commonly used method during the inspection of composite structures at the production and exploitation stage. Describing the ultrasonic method, the focus was put on echo pulse technique and the use of modern Phased Array heads. Incompatibilities most frequently occurring and detected in composite materials with thermosetting and thermoplastic matrix were listed and described. A thermoplastic flat composite panel made of carbon pre-impregnate in a high-temperature matrix (over 300°C), which was the subject of the study, was described. The results of non-destructive testing (ultrasonic method) of thermoplastic panel were presented and conclusions were drawn.

Study of Porosity of Carbon Reinforced Plastic Composites Using Broadband Ultrasound Structuroscopy Techniques

2017 ◽  
Vol 755 ◽  
pp. 44-51
Author(s):  
Anton S. Bychkov ◽  
Alexander A. Karabutov ◽  
Elena V. Savateeva ◽  
Yulia G. Sokolovskaya ◽  
Vasily P. Zarubin ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Metal Matrix ◽  
Elastic Moduli ◽  
Epoxy Composites ◽  
Ultrasonic Spectroscopy ◽  
Isotropic Composite ◽  
Plastic Composites ◽  
Reinforced Plastic ◽  
Local Porosity ◽  
Longitudinal Acoustic Waves

Theoretical assessments are given for the use of the through-transition technique of broadband ultrasonic spectroscopy to determine porosity of heterogeneous materials. Experimental measurements of local porosity of composites using the through-transition technique are presented. Dependences of elastic moduli on the concentration of hardening particles and porosity of metal matrix isotropic composite found. Experimental relationship between the phase velocity of longitudinal acoustic waves and the power of structural noise in samples of graphite epoxy composites is obtained.

scholarly journals An Overview of Acoustic Impedance Measurement Techniques and Future Prospects

Metrology ◽  
2021 ◽  
Vol 1 (1) ◽  
pp. 17-38
Author(s):  
Nandeesh Hiremath ◽  
Vaibhav Kumar ◽  
Nicholas Motahari ◽  
Dhwanil Shukla
Keyword(s):  
Acoustic Impedance ◽  
Sound Pressure ◽  
Acoustic Pressure ◽  
Measurement Techniques ◽  
Impedance Measurement ◽  
Acoustic Medium ◽  
Future Prospects ◽  
Reverberation Chamber ◽  
Field Techniques ◽  
Acoustic Phenomenon

In order to progress in the area of aeroacoustics, experimental measurements are necessary. Not only are they required for engineering applications in acoustics and noise engineering, but also they are necessary for developing models of acoustic phenomenon around us. One measurement of particular importance is acoustic impedance. Acoustic Impedance is the measure of opposition of acoustical flow due to the acoustic pressure. It indicates how much sound pressure is generated by the vibration of molecules of a particular acoustic medium at a given frequency and can be a characteristic of the medium.The aim of the present paper is to give a synthetic overview of the literature on impedance measurements and to discuss the advantage and disadvantage of each measurement technique. In this work, we investigate the three main categories of impedance measurement techniques, namely reverberation chamber techniques, impedance tube techniques, and far-field techniques. Theoretical principles for each technique are provided along with a discussion on historical development and recent advancements for each technique.

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