scholarly journals ACOUSTIC NON-DESTRUCTIVE TESTING OF MULTILAYERED STRUCTURES FROM PCM DURING THE PRODUCTION AND OPERATION OF AVIATION TECHNIQUE

2019 ◽  
pp. 36-49
Author(s):  
A. M. Slyadnev
Keyword(s):  
Composite Materials ◽  
Frequency Control ◽  
Low Frequency ◽  
Flaw Detector ◽  
Impedance Method ◽  
Multilayer Structures ◽  
Destructive Testing ◽  
Multilayered Structures ◽  
Effective Use ◽  
Production And Operation

Considered the use in the production of aviation equipment (airplanes and helicopters), polymer composites differing in enhanced operational and technological properties, such as strength, rigidity, level of working temperatures, etc. Examples are given of using newer gliders in multilayer structures MS-21 aircraft and Mi-38 helicopter of modern composite materials. The review of defects of multilayer structures made of polymer composite materials arising at the stage of manufacturing, storage, transportation and operation of aircraft, and low-frequency methods of their control is presented. It is noted that the main of low-frequency control methods are the impedance method and the method of free oscillations proposed by domestic scientists.The principle of operation of the first portable multifunctional computerized pulsed flaw detector DAMI-C09, combining impedance, impact and eddy current ND methods, is described. It is noted that the flaw detector can be used for manual and automated, as part of a robotic complex, to identify bundles, nonglues and other violations of the integrity of composites, honeycomb structures and glued structures, to determine corrosion centers, surface and internal defects in non-ferromagnetic materials. A feature of the flaw detector is the simplified preparation process for work due to the automated mode of tuning the signal in amplitude or phase using a spectrum analyzer, documenting the monitoring results with the ability to transfer to a computer and subsequent processing with the help of a special APM of the Flaw Detector. Examples of the effective use of the flaw detector in the production and operation of aviation equipment are given.

scholarly journals Using Hilbert Transform in Diagnostic of Composite Materials by Impedance Method

2020 ◽  
Vol 64 (4) ◽  
pp. 334-342 ◽  
Author(s):  
Volodymyr Eremenko ◽  
Artur Zaporozhets ◽  
Vitalii Babak ◽  
Volodymyr Isaienko ◽  
Kateryna Babikova
Keyword(s):  
Composite Materials ◽  
Nondestructive Testing ◽  
Hilbert Transform ◽  
Instantaneous Frequency ◽  
Information Quality ◽  
Low Frequency ◽  
Mechanical Impedance ◽  
Phase Characteristic ◽  
Impedance Method ◽  
Materials Testing

The article is devoted to the problem of the increasing of information quality for the impedance method of nondestructive testing. The purpose of this article is to get for the pulsed impedance method of nondestructive testing the additional informative parameters. Instantaneous values of the information signal's amplitude is a sensitive parameter to the effects of interference, in particular friction, which necessitates the use of additional informative features. It was experimentally measured signals from defective and defectless areas of the test pattern. Using of the Hilbert transform gave possibility to determine phase characteristics of these signals and realize demodulation to extract a low-frequency envelope for further analysis of its shape. It was received the informative features as a result of researches. Among them are instantaneous frequency of a signal, the integral of a phase characteristic on the selected interval and the integral of a difference signal phase characteristics. In order to compare quality of the defect detection using selected parameters it was carried out evaluation of the testing result reliability for a product fragment made of a composite material. Considering the influence of the change in the mechanical impedance of the researched area on the phase-frequency characteristics of the output signal of the converter, it is proposed to use as the diagnostic signs: the instantaneous frequency and the value of the phase characteristic of the current signal for certain points in time. The proposed informative features enable to increase general reliability of composite materials testing by the pulsed impedance method.

Review of piezoelectric impedance based structural health monitoring: Physics-based and data-driven methods

2021 ◽  
pp. 136943322110384
Author(s):  
Xingyu Fan ◽  
Jun Li ◽  
Hong Hao
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Structural Damage ◽  
Low Frequency ◽  
Data Driven ◽  
Mode Shapes ◽  
Monitoring Methods ◽  
Destructive Testing ◽  
Electromechanical Impedance ◽  
Structural Health

Vibration based structural health monitoring methods are usually dependent on the first several orders of modal information, such as natural frequencies, mode shapes and the related derived features. These information are usually in a low frequency range. These global vibration characteristics may not be sufficiently sensitive to minor structural damage. The alternative non-destructive testing method using piezoelectric transducers, called as electromechanical impedance (EMI) technique, has been developed for more than two decades. Numerous studies on the EMI based structural health monitoring have been carried out based on representing impedance signatures in frequency domain by statistical indicators, which can be used for damage detection. On the other hand, damage quantification and localization remain a great challenge for EMI based methods. Physics-based EMI methods have been developed for quantifying the structural damage, by using the impedance responses and an accurate numerical model. This article provides a comprehensive review of the exciting researches and sorts out these approaches into two categories: data-driven based and physics-based EMI techniques. The merits and limitations of these methods are discussed. In addition, practical issues and research gaps for EMI based structural health monitoring methods are summarized.

Time-domain spectral element method for modelling of the electromechanical impedance of disbonded composites

2018 ◽  
Vol 29 (16) ◽  
pp. 3214-3221 ◽  
Author(s):  
Piotr Fiborek ◽  
Paweł H Malinowski ◽  
Paweł Kudela ◽  
Tomasz Wandowski ◽  
Wiesław M Ostachowicz
Keyword(s):  
Spectral Element Method ◽  
Spectral Element ◽  
Impedance Method ◽  
Adhesively Bonded ◽  
Destructive Testing ◽  
Electromechanical Impedance ◽  
Carbon Fibre Reinforced Polymer ◽  
Fibre Reinforced Polymer ◽  
Non Destructive ◽  
Element Method

The research focuses on the electromechanical impedance method. The electromechanical impedance method can be treated as non-destructive testing or structural health monitoring approach. It is important to have a reliable tool that allows verifying the integrity of the investigated objects. The electromechanical impedance method was applied here to assess the carbon fibre–reinforced polymer samples. The single and adhesively bonded samples were investigated. In the reported research, the electromechanical impedance spectra up to 5 MHz were considered. The investigation comprised of modelling using spectral element method and experimental measurements. Numerical and experimental spectra were analysed. Differences in spectra caused by differences in considered samples were observed.

The charge mobility in polymer LEDs-the low frequency impedance method

2003 ◽  
Vol 135-136 ◽  
pp. 5-6
Author(s):  
I.N. Hulea ◽  
H.B. Brom ◽  
K. Brunner ◽  
R.F.J.v.d. Scheer ◽  
M.A.J. Michels
Keyword(s):  
Low Frequency ◽  
Impedance Method ◽  
Charge Mobility ◽  
Polymer Leds

Settling Control of the Triple-Stage Hard Disk Drives Using Robust Output Feedback Model Predictive Control

2016 ◽  
Author(s):  
Huy Nguyen ◽  
Omid Bagherieh ◽  
Roberto Horowitz
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Output Feedback ◽  
Frequency Control ◽  
Hard Disk Drives ◽  
Low Frequency ◽  
Hard Disk ◽  
Control Input ◽  
Feedback Model ◽  
Actuator Constraints

Track settling control for a hard disk drive with three actuators has been considered. The objective is to settle the read/write head on a specific track by following the minimum jerk trajectory. Robust output feedback model predictive control methodology has been utilized for the control design which can satisfy actuator constraints in the presence of noises and disturbances in the system. The controller is designed based on a low order model of the system and has been applied to a higher order plant in order to consider the model mismatch at high frequencies. Since the settling control generally requires a relatively low frequency control input, simulation result shows that the head can be settled on the desired track with 10 percent of track pitch accuracy while satisfying actuator constraints.

scholarly journals Defect Estimation in Non-Destructive Testing of Composites by Ultrasonic Guided Waves and Image Processing

Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 315 ◽  
Author(s):  
Kumar Anubhav Tiwari ◽  
Renaldas Raisutis ◽  
Olgirdas Tumsys ◽  
Armantas Ostreika ◽  
Kestutis Jankauskas ◽  
...  
Keyword(s):  
Image Processing ◽  
Composite Structures ◽  
Guided Waves ◽  
Low Frequency ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Discrete Wavelet ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive

The estimation of the size and location of defects in multi-layered composite structures by ultrasonic non-destructive testing using guided waves has attracted the attention of researchers for the last few decades. Although extensive signal processing techniques are available, there are only a few studies available based on image processing of the ultrasonic B-scan image to extract the size and location of defects via the process of ultrasonic non-destructive testing. This work presents an image processing technique for ultrasonic B-scan images to improve the estimation of the location and size of disbond-type defects in glass fiber-reinforced plastic materials with 25-mm and 51-mm diameters. The sample is a segment of a wind turbine blade with a variable thickness ranging from 3 to 24 mm. The experiment is performed by using a low-frequency ultrasonic system and a pair of contact-type piezoceramic transducers kept apart by a 50-mm distance and embedded on a moving mechanical panel. The B-scan image acquired by the ultrasonic pitch-catch technique is denoised by utilizing features of two-dimensional discrete wavelet transform. Thereafter, the normalized pixel densities are compared along the scanned distance on the region of interest of the image, and a −3 dB threshold is applied to the locations and sizes the defects in the spatial domain.

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