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The Possibility of Application of the Acoustic Emission Method for Monitoring Friction Processes

Abstract

This article presents the methodology and research results of monitoring friction processes between couple of cooperating elements by acoustic emission method. The research was carried out at the lathing machine test stand of the Technische Hochschule Mittelhessen. The test stand included lathing machine Proxon PD 210, shaft, made of austenitic stainless steel X2CrNi18-9 and steel plate, made of S235. The Friction process was monitored by an acoustic emission set made by Physical Acoustics Corporation (PAC). The PAC system includes: preamplifier USB AE Node, type 1283 with bandpass 20 kHz – 1 MHz, AE signal measurement sensor type VS 150M, with a frequency range 100-450 kHz, computer with AE Win for USB Version E5.30 software. During the study, the acoustic emission (AE) generated by friction between shaft and steel plate was recorded. The load of the plate was 0, 1, 2, 3, 4, 5 and 10 N. The following parameters were determined: amplitude, number of events – hits, the effective value of the signal (RMS). The use of grease between the cooperating elements caused a significant reduction in friction and thus the power of the generated signal (10 to 30 times). In the case of dry friction, without grease, the maximum RMS value was recorded at 4 N load and at the lubricant between the pair cooperating at 1 N load. The research has shown that it is possible to monitor the friction process between cooperating elements using the acoustic emission method.

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Monitoring of underdeck corrosion by using acoustic emission method

ABSTRACT

This paper presents first short characteristics of underdeck corrosion process as well as a problem of its monitoring. Next is described an acoustic emission (AE) method elaborated by Department of Ship Technology, Quality Systems and Material Engineering, Gdańsk University of Technology in cooperation with partners of CORFAT project realized within 7th EU Frame Program. Further are presented short characteristics of the emission process, used measuring instrumentation of Vallen Systeme GmbH, as well as TESTER, corrosion testing device, and a corrosion solution used in the tests. Finally, results of the tests performed on selected marine units, are presented.

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The Possibility of Applying Acoustic Emission Method for Monitoring Lathing Process

Abstract

Nowadays acoustic emission (AE) method is used in many fields of science, including in the diagnosis and monitoring of machining processes such as turning, grinding, milling, etc. Monitoring of turning process allows ensuring stable conditions of treatment. Stable conditions of turning process have a great impact on the quality of the surface. This is especially important during finishing treatment.

The research was carried out on a universal ZMM-SLIVEN CU500MRD lathe centre-using tool with removable insert SANDVIK Coromant WNMG 080408 – WMX Wiper. Lathing process was performed on the shaft of 74 mm in diameter made of S235 steel.

The research was carried out at constant cutting speed v = 230 m/min. Changed parameters were feed f = 0.1; 0.2; 0.4 mm/rev and cutting depth ap = 0.5; 0.75; 1 mm. In the research was used a set of acoustic emission Vallen System. The kit includes: 4 channel signal recorder AMSY 6, two measurement modules ASIP-2/S, preamplifier with a frequency range 20 kHz – 1 MHz and the strengthening of 34dB and AE signal measurement sensor type VS 150M, with a frequency range 100 – 450 kHz. During the study, the acoustic emission (AE) generated during the lathing process were recorded parameters e.g. amplitude, number of events – hits, the effective value of the signal (RMS).

The test results indicate, that the higher instability of the process was during turning with parameters: ap = 0.75 mm and f = 0.1 mm/rev. The study can be the basis for the use of acoustic emission method for monitoring lathing process to ensure stable conditions of that process and the same to obtain a high quality surface.

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Tensile Damage Mechanism of 3-D Angle-Interlock Woven Composite using Acoustic Emission Events Monitoring

Abstract

The quasi-static tensile damage behavior of one type of layer-to-layer 3-Dimensional Angle-interlock Woven Composite (3DAWC) was tested and analyzed in this paper. Incorporated with the acoustic emission (AE) events monitoring, the mechanical behavior of the 3DAWC under tensile loading condition was characterized. The Load-Extension curve, Load/AE events-Time curves occurred during the entire testing process and tensile damage modes were recorded to characterize and summarize the mechanical properties and damage mechanism of the 3DAWC subjected to tensile loading. It was found that the tensile damage of the 3DAWC could be summarized into 3 steps. And each step has a distinct primary damage mode. Moreover, the resin cracks, resin-yarn interface debonding and yarn breakages were the main damage modes for the 3DAWC.

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Results of acoustic emission tests of corrosion protection degree of ship steel tanks covered by means of protective coatings (Phase I)

. Eliasson J.: Economic of coating/corrosion protection of ships selecting the correct type of anticorrosion protection for underwater applications on new buildings. Lloyd's List events Conference "Prevention and Management of Marine Corrosion", London, April 2003. Buglacki H., Smajdor M.: Possibilities of Acoustic Emission (AE) application to assessment of hull plates and tanks of ships. CORRET Project, Gdańsk University of Technology, Gdańsk, 2007. Buglacki H.: Assessment method of corrosion protection degree of

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Meso Mechanical Study of Cracking Process in Concrete Subjected to Tensile Loading

Abstract

This project focused on how the cracking process in concrete is influenced by both the micro and meso structures of concrete. The aim was to increase knowledge pertaining to the effect of critical parameters on the cracking process and how this is related to the material’s macroscopic properties. A methodology based on the combination of different experimental methods and measuring techniques at different scales was developed. Crack propagation during tensile loading of small-scale specimens in a tensile stage was monitored by means of Digital Image Correlation (DIC) and Acoustic Emission (AE). After testing, crack patterns were studied using fluorescence microscopy.

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Detection and analysis of series arc using non-conventional methods in low-voltage switchboards

Abstract

Detection and analysis of series arc in low-voltage switchboards have significant meaning for preventing the electrical fires. However, the conventional current and voltage methods have low a sensitivity to sense the minute arc discharge, leading to the fail operation of arc fault circuit interrupter. Therefore, this paper dealt with the application of non-conventional methods, including the ultra-violet (UV), acoustic emission (AE), and transient earth voltage (TEV) sensor in arc detection, for the purpose of improving the detection sensitivity and reducing the potential electric fires. Three types of typical arc faults in low-voltage switchboards were simulated and the actual detection environment was configured. From the results, the wavelength of UV light emitted from arc was 200–400 nm and the arc-induced AE signal had a frequency range of 40–600 kHz. The TEV signals generated from three types of arc faults presented different frequency spectrums, based on which the time-frequency map was used to classify the fault type.

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MODELLING OF ACOUSTIC EMISSION SOURCE AND WAVE RESPONSE IN LAYERED MATERIALS

Abstract

This study proposes a model of wave propagation in layered media for the use in acoustic emission (AE) studies. This model aims to find an AE response at a free surface to the propagating waves originating at a dislocation source either in one layer medium or a layer-to-layer interface. Each of the layered media is assumed to be homogenous, linear elastic and isotropic. An integral transformation method has been applied to determine the wave response in frequency-wave number domain, which is then converted to time-space domain. In the numerical examples, we first select truncated values with the finite integral transformation, so that no wave interference happens in the responses from wave reflection at truncated boundaries. Next, we simulate wave propagation in an elastic half space, and compare results obtained with that from other kind bottom boundary. Next, we introduce a dis- location source in interface and compare a simulated AE wave response obtained with that computed in the layered medium to demonstrate the performance of the model. In each simulation, the results show good agreement with the reference solutions.

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Analysis of the Possibility of Using Acoustic Emission for Monitoring Technical Condition of the Fuel Injector in 3AL25/30 Engine

Abstract

Acoustic emission method (AE) can be used for the diagnosis of machine parts such as, for example: fuel injectors. This paper presents the methodology and research results of 3AL25/30 engine fuel injector. During research was studied one injector in good condition and second with simulated failure involving closing 2 of 9 holes of the injector tip. Research was carried out on a laboratory test stand using a set of acoustic emission Vallen System. This set included: 4 channel signal recorder AMSY 6, two measurement modules ASIP-2/S, preamplifier with a frequency range 20 kHz-1 MHz and the strengthening of 34 dB, AE signal measurement sensor type VS 150M, with a frequency range 100-450 kHz. During the study, the acoustic emission (AE) generated by tested injector was recorded. The following parameters were determined: amplitude, rise time, duration time, total time, number of events – hits, the effective value of the signal (RMS). Analysis of the results showed significantly longer total time of the injection in the case of damaged injector compared to the injector in good conditions. Signal amplitude was higher, however, the RMS signal reached approximately 3-times lower value for the injector with damaged tip. This means lower quality fuel atomization. Laboratory test results were compared with signals recorded on injectors installed in the engine. Analysis of the signals allowed detection damage of the injector installed in the engine during normal operation.

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Evaluation of Impact Damage in Composite Structures Using Ultrasonic Testing

Structures 62(2): pp. 193-203. [11] Gdoutos E. E. (2005): Fracture Mechanics: An Introduction. Vol. 123 of Solid Mechanics and Its Applications . 2nd edn. Springer Netherlands. [12] Talreja R. and Singh C. V. (2012): Damage and Failure of Composite Materials . Cambridge University Press. New York. [13] Huang J. Q. (2013): 2 – Non-destructive evaluation (NDE) of composites: acoustic emission (AE) . In: Non-Destructive Evaluation (NDE) of Polymer Matrix Composites, V. M. Karbhari (Ed.). Woodhead Publishing Series in Composites Science and Engineering

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