Resonant Airborne Acoustic Emission for Nondestructive Testing and Defect Imaging in Composites

A new version of an acoustic emission mode which is different from its traditional counterpart is discussed in view of applications for nondestructive testing. It is based on the effect of acoustic waves generation from the defect area in ambient air by local standing wave vibration developed in this area at the defect resonant frequency. Another approach which does not require preliminary knowledge of local defect-resonance frequency is one that uses wideband acoustic activation by a noise-like input signal. The acoustic emission field from the defect area is a “fingerprint” of the radiation source, and thus is applicable to defect detection and imaging. This enables the use of commercial microphone scanning for detecting and imaging various defects in composites. An improvement in the acoustic-emission scanning mode based on a multiple-axis robot is studied to applications to complex shape components. A rapid, full-field imaging of the acoustic-emission field is implemented by means of an array of microphones (acoustic camera). Numerous case studies validate the potential of the resonant acoustic-emission modes for integration in the defect imaging system based on inexpensive, fully acoustic instrumental components.

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The influence of ultrasound signal parameters on sonoluminescence light intensity

Archives of Electrical Engineering ◽

10.2478/aee-2013-0048 ◽

2013 ◽

Vol 62 (4) ◽

pp. 605-612

Author(s):

Marek Szmechta ◽

Tomasz Boczar ◽

Dariusz Zmarzły

Keyword(s):

Acoustic Emission ◽

Acoustic Waves ◽

Power Transformer ◽

Electrical Power ◽

Partial Discharges ◽

Research Project ◽

Insulation Systems ◽

Secondary Phenomenon ◽

New Research ◽

The Relationship

Abstract Topics of this article concern the study of the fundamental nature of the sonoluminescence phenomenon occurring in liquids. At the Institute of Electrical Power Engineering at Opole University of Technology the interest in that phenomenon known as secondary phenomenon of cavitation caused by ultrasound became the genesis of a research project concerning acoustic cavitation in mineral insulation oils in which a number of additional experiments performed in the laboratory aimed to determine the influence of a number of acoustic parameters on the process of the studied phenomenona. The main purpose of scientific research subject undertaken was to determine the relationship between the generation of partial discharges in high-voltage power transformer insulation systems, the issue of gas bubbles in transformer oils and the generated acoustic emission signals. It should be noted that currently in the standard approach, the phenomenon of generation of acoustic waves accompanying the occurrence of partial discharges is generally treated as a secondary phenomenon, but it can also be a source of many other related phenomena. Based on our review of the literature data on those referred subjects taken, it must be noted, that this problem has not been clearly resolved, and the description of the relationship between these phenomena is still an open question. This study doesn’t prove all in line with the objective of the study, but can be an inspiration for new research project in the future in this topic. Solution of this problem could be a step forward in the diagnostics of insulation systems for electrical power devices based on non-invasive acoustic emission method.

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Experimental study of the dynamic behaviour of High Performance Concrete (HPC) under tensile loading

EPJ Web of Conferences ◽

10.1051/epjconf/201818302043 ◽

2018 ◽

Vol 183 ◽

pp. 02043 ◽

Cited By ~ 1

Author(s):

Bratislav Lukić ◽

Dominique Saletti ◽

Pascal Forquin

Keyword(s):

High Speed ◽

High Performance ◽

High Performance Concrete ◽

Imaging System ◽

Spall Strength ◽

High Speed Imaging ◽

Dynamic Tensile Strength ◽

Full Field ◽

Local Point ◽

Measurement Results

This paper presents the measurement results of the dynamic tensile strength of a High Performance Concrete (HPC) obtained using full-field identification method. An ultra-high speed imaging system and the virtual fields method were used to obtain this information. Furthermore the measurement results were compared with the local point-wise measurement to validate the data pressing. The obtained spall strength was found to be consistently 20% lower than the one obtained when the Novikov formula is used.

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Multi-kernel deconvolution for contrast improvement in a full field imaging system with engineered PSFs using conical diffraction

Optics and Lasers in Engineering ◽

10.1016/j.optlaseng.2017.08.008 ◽

2018 ◽

Vol 100 ◽

pp. 161-169 ◽

Cited By ~ 1

Author(s):

Jose M. Enguita ◽

Ignacio Álvarez ◽

Rafael C. González ◽

Jose A. Cancelas

Keyword(s):

Imaging System ◽

Full Field ◽

Field Imaging

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Application and evaluation of the technical condition of composite materials in aircraft and unmanned aerial vehicles by acoustic emission method of nondestructive testing

Advanced Engineering Research ◽

10.23947/2687-1653-2021-21-4-328-336 ◽

2022 ◽

Vol 21 (4) ◽

pp. 328-336

Author(s):

A. V. Popov ◽

A. O. Samuylov ◽

I. S. Cherepanov

Keyword(s):

Acoustic Emission ◽

Composite Materials ◽

Nondestructive Testing ◽

Unmanned Aerial Vehicles ◽

Technical Condition ◽

Acoustic Emission Method ◽

Emission Method ◽

Software Complex ◽

Aerial Vehicles ◽

Aerial Vehicle

Introduction. The paper analyzes the application of composite materials as the main determining method of reducing the mass of the airframe and an unmanned aerial vehicle. Advanced nondestructive testing methods provide assessing the technical condition of these materials, as well as determining stress concentrators on the airframe and an unmanned aerial vehicle with high accuracy in order to make a decision on the further operation of this object under control. The objective of the work was to increase the accuracy and efficiency of the assessment of crack resistance of composite materials through the acoustic emission control.Materials and Methods. This paper presents the nomenclature of composite materials used in the construction of various aircraft, including unmanned aerial vehicles. The most possible probable defects of these materials due to the influence of operational factors are presented. The applied methods of nondestructive testing of composite material and selection of the most suitable one according to specific advantages were compared. An experiment was carried out to determine the strength limits of carbon fiber using a hardware and software complex by acoustic emission method. The research results are presented in the form of drawings projected by the hardware and software complex.Results. The application of the acoustic-emission method of composite material control is described.Discussion and Conclusions. The results obtained experimentally can be used in the process of determining the strength limits of various composite materials by the acoustic emission method of nondestructive testing to assess the technical condition in mechanical engineering, shipbuilding, and aircraft construction. The paper is recommended to researchers involved in the design of aircraft and unmanned aerial vehicles.

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Development of a Compact, Configurable, Real-Time Range Imaging System

10.26686/wgtn.16985239 ◽

2021 ◽

Author(s):

◽

Adrian Peter Paul Jongenelen

Keyword(s):

High Speed ◽

Imaging System ◽

Modulation Frequency ◽

Image Sensor ◽

Measurement Precision ◽

Operating Parameters ◽

Range Imaging ◽

Field Range ◽

Full Field ◽

Precision And Accuracy

<p>This thesis documents the development of a time-of-flight (ToF) camera suitable for autonomous mobile robotics applications. By measuring the round trip time of emitted light to and from objects in the scene, the system is capable of simultaneous full-field range imaging. This is achieved by projecting amplitude modulated continuous wave (AMCW) light onto the scene, and recording the reflection using an image sensor array with a high-speed shutter amplitude modulated at the same frequency (of the order of tens of MHz). The effect is to encode the phase delay of the reflected light as a change in pixel intensity, which is then interpreted as distance. A full field range imaging system has been constructed based on the PMD Technologies PMD19k image sensor, where the high-speed shuttering mechanism is builtin to the integrated circuit. This produces a system that is considerably more compact and power efficient than previous iterations that employed an image intensifier to provide sensor modulation. The new system has comparable performance to commercially available systems in terms of distance measurement precision and accuracy, but is much more flexible with regards to its operating parameters. All of the operating parameters, including the image integration time, sensor modulation phase offset and modulation frequency can be changed in realtime either manually or automatically through software. This highly configurable system serves as an excellent platform for research into novel range imaging techniques. One promising technique is the utilisation of measurements using multiple modulation frequencies in order to maximise precision over an extended operating range. Each measurement gives an independent estimate of the distance with limited range depending on the modulation frequency. These are combined to give a measurement with extended maximum range using a novel algorithm based on the New Chinese Remainder Theorem. A theoretical model for the measurement precision and accuracy of the new algorithm is presented and verified with experimental results. All distance image processing is performed on a per-pixel basis in real-time using a Field Programmable Gate Array (FPGA). An efficient hardware implementation of the phase determination algorithm for calculating distance is investigated. The limiting resource for such an implementation is random access memory (RAM), and a detailed analysis of the trade-off between this resource and measurement precision is also presented.</p>

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A mobile nondestructive testing (NDT) system for fast detection of impact damage in fiber-reinforced plastics (FRP)

Journal of Sensors and Sensor Systems ◽

10.5194/jsss-9-43-2020 ◽

2020 ◽

Vol 9 (1) ◽

pp. 43-50 ◽

Cited By ~ 1

Author(s):

Johannes Rittmann ◽

Markus Rahammer ◽

Niels Holtmann ◽

Marc Kreutzbruck

Keyword(s):

Nondestructive Testing ◽

Impact Damage ◽

Local Defect ◽

Fiber Reinforced ◽

Frequency Sweep ◽

Ir Camera ◽

Reinforced Plastics ◽

Part Surface ◽

Fiber Reinforced Plastics ◽

Impact Damages

Abstract. Impact damage in fiber-reinforced plastics, such as carbon-fiber-reinforced plastics (CFRP) and glass-fiber-reinforced plastics (GFRP), involves high challenges to nondestructive testing (NDT). The anisotropic material structure significantly complicates the interpretation of results in conventional testing. Resonant frequency sweep thermography (RFST) based on local defect resonance combined with well-known ultrasonic thermography enables the fast and simple detection of relevant impact damages. RFST utilizes frequency sweep excitation in the low- and mid-kilohertz range to activate defect resonances with low acoustical power of a few megawatts. Resonances of defects amplify the acoustic vibration amplitude by more than 1 order of magnitude and lead to a significant enhancement of the corresponding thermal signal. This is based on both crack friction and/or visco-elastic heating and can be detected at the part surface by an infrared camera. The defect detection threshold depends on excitation power and the distance between the defect and the ultrasonic source. For this new NDT approach, a first prototype system in the form of a tripod with an integrated infrared (IR) camera and ultrasonic excitation was developed. It stands out due to its simple handling and flexible applications. Augmented reality assists the inspector to interpret the results and mark the defect by projecting the evaluated test result onto the part surface. In this article, the first results from a series of impact damages in CFRP of varying impact energies and crack sizes are presented.

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Dual-Laser Integrated Microwave Imaging System for Nondestructive Testing of Construction Materials and Structures

IEEE Transactions on Instrumentation and Measurement ◽

10.1109/tim.2018.2795858 ◽

2018 ◽

Vol 67 (6) ◽

pp. 1329-1337 ◽

Cited By ~ 6

Author(s):

Paritosh Giri ◽

Sergey Kharkovsky

Keyword(s):

Nondestructive Testing ◽

Imaging System ◽

Construction Materials ◽

Microwave Imaging ◽

Dual Laser

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Evaluation of Fatigue Crack Growth Characteristics on Stainless Steel SS 316 LN Using Acoustic Emission Technique

Volume 3: Advanced Materials: Design, Processing, Characterization, and Applications ◽

10.1115/imece2020-23751 ◽

2020 ◽

Author(s):

Raghu V. Prakash ◽

Manuel Thomas

Keyword(s):

Stainless Steel ◽

Acoustic Emission ◽

Fatigue Crack ◽

Elevated Temperature ◽

Fatigue Crack Growth ◽

Crack Growth ◽

Acoustic Waves ◽

Crack Advance ◽

Cumulative Energy ◽

Good Correspondence

Abstract Results of online acoustic emission (AE) monitoring during fatigue crack growth rate (FCGR) experiments on a stainless steel SS 316 LN are presented in this paper. Two specimen geometries — viz., standard compact tension (C(T)) specimens as well as side-grooved C(T) specimens were considered for experiments at ambient temperature and at 600°C (873K). There is a good correspondence between crack length increment and the increase in AE cumulative count and cumulative energy during the experiments. The side grove introduced on the thickness direction of the test specimen constrains the plastic zone ahead of the crack tip, thereby enforcing plane strain conditions at the crack. Reduced AE activity at initial stages of crack growth was observed for side grooved samples. The transition to Stage-II crack growth was observed using acoustic emission (AE) technique which otherwise was not visible from the fatigue crack growth plot. The work further attempts to correlate the AE parameters obtained during elevated temperature (873K) fatigue crack growth in stainless steel. For the purpose of acquiring AE signals outside the heated zone, a waveguide was used to transmit the acoustic waves from the specimen at high temperature. A correlation between crack advance and AE parameters was obtained from the elevated temperature tests.

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