Smart Diagnostics V

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Authors: Kamil Lubikowski, Stanisław Radkowski, Krzysztof Szczurowski, Michał Wikary
Abstract: Actually in motor industry, specialty in car market is tender to maximum utilization of energy included in fuel air mixture, which most of part of burning process is lost. In todays times Peltier module are generally available, which is mainly used in coolers for keeping of low temperature. They make use of Peltier phenomenon, relying on power module from electric net for manufactured low temperature on cold side that module. Module producers usually available voltages characteristics thats working modules.In realize research use that same modules but for recuperate electrical energy from temperature. Research target was in temperature equivalent on cold side and warm side check value of manufactured voltage from these modules. Utilized of Seebeck phenomenon depends on heat of warm side with simultaneously cool module cold side which manufacture electricity.In effect realize research findings series of results for which equivalent characteristics describing those module capacities. The first influence from realize research is fact that characteristics isnt identical with characteristics for that same modules manufactured low temperature.
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Authors: Ziemowit Dworakowski, Łukasz Ambroziński, Pawel Packo, Krzysztof Dragan, Tadeusz Stepinski, Tadeusz Uhl
Abstract: Lamb waves (LW) are used for damage detection and health monitoring due to the long range propagation ability and sensitivity to structural integrity changes as well as their robustness in different applications. However, due to the dispersive character and multimode nature of LWs, analysis of the acquired ultrasonic signals is very complex. It becomes even more difficult when applied to a complex structure, for instance, an aircraft component with riveted joints and stringers characterized by difficult geometries. Therefore, numerous approaches to the evaluation of damage indices have been proposed in the literature. In this paper, comparison a number of damage indices applied to LWs testing in aircraft aluminum panels. The damage indices, known from the literature have been selected from the application point of view. Artificial neural network has been used for the classification of fatigue cracks and artificial damages induced in the specimens taken from a real aircraft structure. Article presents results of simulation, data analysis and data classification obtained using selected and dedicated neural network. The main aim of the presented research was to develop signal processing and signal classification methods for an aircraft health monitoring system. The article presents a part of the research carried out in the project named SYMOST.
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Authors: Piotr Kohut, Krzysztof Holak, Tadeusz Uhl, Jędrzej Mączak, Przemysław Szulim
Abstract: Structural Health Monitoring (SHM) is an emerging field of technology that involves the integration of sensors, data transmission, processing and analysis for detection, as well as localization and assessment of damage which can lead to its failure in the future [1,. In general, SHM methods can be divided into two groups: local and global ones. The second group can be applied if a global change in the geometry of a structure can be observed. In practice, the most commonly used methods of damage detection are based on the analysis of variations in various dynamic properties caused by damage [3,. However, the excitation of large structures can be costly and difficult. The acquisition of static deflection requires much less effort, which makes the damage detection methods based on changes in deflection curves more attractive for practical use [5-1. Damage detection and localization methods require a densely sampled deflection curve.
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Authors: Dorota Włodarska, Andrzej Klepka, Wieslaw Jerzy Staszewski, Tadeusz Uhl
Abstract: Nonlinear acoustics deals with various nonlinear effects that occur in ultrasonic wave propagation. The method is suitable for material characterisation, as it uses different nonlinear phenomena associated with material imperfections. The method has been used for detecting nonlinearities in cracked solids by: measuring distortions of acoustic signals, estimating resonance frequency shifts or assessing nonlinear vibro-acosutic modulations. The latter is the most widely used non-classical approach to probe material nonlinearities. The method involves vibro-acoustic interactions of ultrasonic wave and modal vibration in damaged specimens. Modulation intensity that strongly relates to damage severity - is usually assessed in the frequency domain and often leads to confusing results when large modulations are involved. The paper investigates the time domain analysis of vibro-acoustic modulated signals. Several methods for instantaneous frequency calculation used to assess the intensity of modulation - are compared. Simulated and experimental data are used in these investigations.
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Authors: Ifigeneia Antoniadou, Keith Worden, Graeme Manson, Nikolaos Dervilis, S.G. Taylor, Charles R. Farrar
Abstract: The RAPTOR telescope systems are astronomical observatories that operate in remote locations in New Mexico searching for astrophysical transients called gamma-ray bursts. Their operating condition should remain at good levels in order to have accurate observations. Currently, the first component of the RAPTOR telescopes to fail is a capstan driving mechanism that operates in a run-to failure mode. The capstans wear relatively frequently because of their manufacturing material and can cause damage to other more expensive components, such as the drive wheels and the telescope optics. Monitoring the condition of these systems seems a reasonable solution since the unpredictable rate at which the capstans experience wear, in combination with the remote locations and high duty cycles of these telescope systems, make it unprofitable to choose a strategy of replacing the capstans at chosen intervals. Experimental tests of the telescope systems reported here recorded vibration signals during clockwise and counterclockwise rotations, similar to a motion known as "homing-sequence". The Empirical Mode Decomposition (EMD) method in combination with the Hilbert Transform (HT) and a new alternative method for the estimation of the instantaneous features of a signal that applies an energy tracking operator, called Teager-Kaiser Energy operator, and an energy separation algorithm to the data being analysed, are the time-frequency analysis methods used for analysis here.
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Authors: Mateusz Rosiek, Krzysztof Dragan, Adam Martowicz, Tadeusz Uhl
Abstract: This work is devoted to the use of the electromechanical impedance method for the damage detection in a riveted aircraft element. In the first part of the paper a theoretical background of the impedance-based damage detection technique is made. Next, the description of the utilised experimental set-up is described. Then, an application of the method used to detect damage in a wing sheathing of a turboprop training aircraft is presented. A damage scheme incorporating multiple notches through the selected rivets is considered. Finally, the suitability of the described method to distinguish close and far field damages is discussed.
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Authors: Leszek Dziczkowski, Sławomir Zolkiewski
Abstract: In the defectoscopic tests by means of the eddy currents method only a certain superficial layer of the tested element is inspected. The reason of this phenomenon is connected with a very important feature of the eddy currents. The induced eddy currents generate its own magnetic field which obstructs penetration for the primary magnetic field. It is crucial to know the penetration depth of eddy currents. It allows planning successfully the diagnosis process. There are two cases worth mentioning: when the eddy current method is treated as the additional method complementary to the ultrasound method (because it does not detect superficial defects) and when the eddy current method is used as the main method for the thin elements diagnosis. The most frequently used evaluation method of eddy currents penetration depth is connected with determination of the e-folding decrease of electric current. The definition is convenient to use because it is simplified by using in the mathematical formula (allowing determination of the depth) frequency of eddy current and conductivity of the diagnosed elements. However the simplifications are not sufficient in practice. When we change the frequency of eddy currents during the survey or the probe then the depth of penetration is also changed, then we can measure the depth of the defects. While measuring the conductivity of a proper material element it is obligatory to prepare an adequate size of the sample that is free of defects. Knowing the value of penetration depth is then very helpful. On the other hand, when we have a sample of a specified size and we want to measure its conductivity then the knowledge of the depth of penetration of eddy currents helps us to select the proper frequency. In the paper there is described a proposal of a different definition of the penetration depth of eddy current, much more useful and accurate according to the authors. To obtain much more precise results, the new eddy current method was proposed. This method takes into account not only the parameters of the diagnosed sample and the eddy current frequency but the characteristic of the measuring device as well. The above mentioned method is based on the universal mathematical model of impact of conductive thin foil on the measuring coil impedance change. The procedure of calculations is easy to carry out online.
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Authors: Wojciech Cholewa, Marcin Amarowicz, Paweł Chrzanowski, Tomasz Rogala
Abstract: Development of effective diagnostic systems for the recognition of technical conditions of complex objects or processes requires the use of knowledge from multiple sources. Gathering of diagnostic knowledge acquired from diagnostic experiments as well as independent experts in the form of an information system database is one of the most important stages in the process of designing diagnostic systems. The task can be supported through suitable modeling activities and diagnostic knowledge management. Briefly, this paper presents an example of an application of multimodal diagnostic statement networks for the purpose of knowledge representation. Multimodal statement networks allow for approximate diagnostic reasoning based on a knowledge that is imprecise or even contradictory in part. The authors also describe the software environment REx for the development and testing of multimodal statement networks. The environment is a system for integrating knowledge from various sources and from independent domain experts in particular.
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Authors: Krzysztof Grabowski, Paulina Zbyrad, Tadeusz Uhl
Abstract: In this paper there wasdevelopeda CNT based sensor applied to the tested material and integrated with it. MWCNTs weremixed with polymer and then applied to the materials (fiber glass composites) with the use of screen printing. The surface and the inner part of the sensing material were investigated using SEM. The most importantand noticeable thing was dispersion of CNTs in epoxy.Moreover, the sensors were tested under the different loads. There were three runs for the same compositions of CNT/epoxy. Results from the test runs were compared to the images from SEM and discussed. Screen printing technique has shown promising results for the application and integration of the sensors on the base materials leading to the conclusion to do more research for the screen printing technique for application of CNT/epoxy sensors for large area appliaction and variant environments.
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