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Practical verification of EMAT transducer parameters
Zlámal, Michal ; Havránek, Zdeněk (referee) ; Beneš, Petr (advisor)
The challenge is familiar with EMAT transducers, their basic characteristics and principles of operation. Inclusion of the theoretical knowledge acquired in Semester work 1 is based on the practical measurement of the frequency characteristics of transmitting and receiving part of laboratory made EMAT transducers. Based on the measured results should be followed by an improved design of sensor to achieve higher sensitivity with the appropriate shape of frequency response. For generating of exciting signal is expected to use LabVIEW programme environment. For credible results of the measurements in a broad range is needed to make broadband power amplifier for the transmitting and low-noise broadband amplifier for receiving part of EMAT transducer.
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Modern trends in radiographic procedures and methods in defectoscopy
Skřivánková, Vendula ; Vlašic, František (referee) ; Juliš, Martin (advisor)
Presented thesis deals with modern trends and techniques in radiographic methods of crack detection which are recently used in engineering practice. In the first part, conventional (analogue) radiography principles based on creating a visible image of tested object to radiographic film are discussed. The next part is aimed to the digital radiography and radioscopy. To digitize existing X-ray film images, application of storage phosphor plates (CR), flat panels (DR) and computed tomography (CT).
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Modern methods in nondestructive testing of materials using ultrasound
Šimeček, Radek ; Stránský, Lubomír (referee) ; Juliš, Martin (advisor)
Theme of this bachelor thesis is nondestructive testing of materials by modern ultrasound methods. In the first part are mentioned defects of mechanical components, which can be detected by ultrasound. This is followed by a description of conventional ultrasound technique, including a list of the major disadvantages and limits. In the second part are analyzed the modern ultrasonic methods TOFD and Phased Array. It describes not only the principle of these techniques, but there are also provided practical examples of their application.
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NONDESTRUCTIVE EVALUATION OF CONCRETE STRUCTURES BY NONLINEAR ULTRASONIC SPECTROSCOPY METHODS
Převorovský, Zdeněk ; Krofta, Josef ; Chlada, Milan
Facilities of nonlinear ultrasonic spectroscopy for defects detection in steel-reinforced concrete structures are discussed in the paper. Results are shown from non-destructive evaluation of concrete block samples reinforced with intact and corroded armature. Seven piezoelectric transducers were glued on the sample surface. One of them was used to harmonic excitation of the structure with frequency f1=45 kHz and stepwise growing amplitude. Among other 6 transducers one was multiplexed as a second transmitter of harmonic signal with f2=217 kHz and remaining sensors were receiving structural response on 2-frequency excitation. Most pronounced spectral differences between samples with corroded and intact reinforcement were observed on amplitude dependence of 3f1/2f1 ratio and f2-3f1 sidebands, which can be considered as nonlinear parameters characterizing concrete damage.
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