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V7: Summary report NEMENUS for SÚJB
Štefan, Jan ; Joch, Jaroslav ; Převorovský, Zdeněk ; Gabriel, Dušan ; Krofta, Josef ; Chlada, Milan ; Kober, Jan ; Masák, Jan ; Kunz, J. ; Ashhab, B.
This is the final report of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). In this report, the most important project results and outputs are presented, as well as a summary of its contributions with respect to long-term technological horizons.
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V6: Report on functional sample NEMENUS
Štefan, Jan ; Joch, Jaroslav ; Převorovský, Zdeněk ; Gabriel, Dušan ; Krofta, Josef ; Chlada, Milan ; Kober, Jan ; Masák, Jan ; Materna, A. ; Kovářík, O. ; Čech, J.
This research report is an integral part of mandatory output V6: FUNCTIONAL SPECIMEN of project TAČR TK01030108: Innovative methods for nuclear plant safety evaluation based on SHM technologies and related procedures - NEMENUS (NEw MEthods for NUclear Safety). The report presents full technical description of the elaborated representative functional specimen (the representative SHM model) and the description of a four-year experimental program.
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Research Report: Representative SHM Model
Převorovský, Zdeněk ; Joch, Jaroslav ; Kober, Jan ; Krofta, Josef ; Chlada, Milan ; Štefan, Jan ; Kunz, J. ; Ashhab, B.
The Research Report is output of the project NEMENUS dealing with methodology development of Structural Health Monitoring (SHM) for nuclear power plant components. SHM incorporates advanced methods for evaluation of structural operating safety. It consists in continuous monitoring of critical structure parts by advanced Nondestructive Testing (NDT) methods enabling assessment of their residual lifetime. The literature search part of this report comprises different aspects of the main problems including history of SHM systems applications at civil and mechanical structures, and also the newest SHM trends in nuclear and non-nuclear industry. The material damage mechanisms in nuclear power plant environment are also discussed in the report. At the report end there is indicated practical realization of the project results and SHM verification on a model structure.
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NDT in Progress 2019
Převorovský, Zdeněk
Already 10th International Workshop NDT in Progress 2019 was organized by the Czech Society for NDT (CNDT) along with the Institute of Thermomechanics of the Czech Academy of Sciences under auspices of ACADEMIA NDT International and European Federation for NDT. This unique biennial Workshops series started in 2001 with the primary aim to get together experienced NDT world experts with young people and students from various academic and industrial branches, allowing them to deeply discuss the latest state-of-the-art and progress in nondestructive testing and evaluation methodologies (NDT/NDE/SHM/CM) and new trends in both research and application areas. \nMain topics of the Workshop covered (not only):\n•Acoustic & ultrasonic methods; acoustic emission; guided waves; phased arrays.\n•Radiographic methods; infrared & terahertz waves testing.\n•Electromagnetic & magnetic methods; optical methods & defects imaging.\n•Signal & Image processing; nonlinear methods; inverse problems; time reversal.\n•Structural health and condition monitoring (SHM/CM).\n•Numerical simulations and modeling in NDT/NDE.\n•NDT for Industry 4.0 and additive manufacturing.\n
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Monitoring techniques for special alloys from some medical prostheses.
Savin, A. ; Vizureanu, P. ; Převorovský, Zdeněk ; Steigmann, R. ; Chlada, Milan ; Krofta, Josef ; Baltatu, M.S. ; Craus, M. L. ; Nový, F.
The paper presents complementary methods for noninvasive evaluation of an exotic class of alloys possible to be used in medical prosthetics. The interest in this study is the analysis of Ti alloys with different concentration of Mo and Si, in order to make the elastic modulus and Poisson ratio reach values appropriate with human bones. The both methods, acoustic emission and resonant ultrasound spectroscopy are proposed as complementary methods for nondestructive evaluation of entire sample volume.
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Analysis of acoustic emission source location precision for general sensor configurations
Chlada, Milan ; Gális, P. ; Převorovský, Zdeněk
Proper sensor placement is the crucial step and a premise for precise acoustic emission (AE) source location estimate. Using the algorithm for finding the shortest ways in discretely defined bodies it is possible to design three parallel tools how to evaluate problematic areas, namely the location sensitivity, similarity and ambiguity maps, available even for discontinuous or anisotropic bodies. To check the numerical forecast of localization capabilities for given sensor configuration, theoretical results were compared with the data measured on the real steam pressure vessel.
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Nonlinear ultrasonic porosimetry of 3D printed metallic parts
Převorovský, Zdeněk ; Krofta, Josef ; Kober, Jan ; Kirschner, A.
Additive manufacturing process optimization requires a feedback from nondestructive testing (NDT) and evaluation. In this contribution are discussed NDT results obtained by nonlinear elastic wave spectroscopy methods to classify presence of defects in Ti-6Al-4V prismatic samples fabricated by electron beam printer. Quantitative calibration of porosity was realized by metallography. The best porosity classification results were obtained by nonlinear wave modulation spectroscopy with chirp excitation and by ESAM (Excitation Symmetry Analysis).
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Computational time reversal method based on finite element method: influence of temperature
Mračko, Michal ; Kolman, Radek ; Kober, Jan ; Převorovský, Zdeněk ; Plešek, Jiří
Time reversal method is used to focus elastic waves to the location of the original source and reconstruct its source time function. The procedure consists of two steps: Frontal task and Reversal task. In the Frontal task, the medium is excited by an arbitrary source, elastic waves propagate through a body of interest and the dynamic response at few points on boundary is recorded. In the second step (say the Reversal task) the response signal is reversed in time and transmitted back into the medium resulting in focusing in the original source location. It is of practical importance to investigate a case when the medium changes its properties between the frontal and reversal wave propagation steps. An example is a problem of transferring experimentally recorded data to a computational model, where discrepancies in geometry, elastic properties and boundary conditions are expected. Our motivation is to develop a methodology for computation of time reversal problems in commercial finite element software. The results prove that this method is extremely sensitive to the change of temperature and one have to pay special attention to tuning of elastic parameters relevant to the\nexperiment.
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Localization of continuous acoustic emission sources using time reversal procedure
Převorovský, Zdeněk ; Krofta, Josef ; Kober, Jan ; Chlada, Milan
A new solution with the help of Time Reversal (TR) signal processing approach is suggested in this paper. It allows planar location of burst AE sources under high background noise using only one transducer, and continuous AE sources with two transducers, both under high background noise from other sources. TR procedure was in this approach applied to long random noise signals for the first time. Suggested method was verified by means of experimentally simulated AE sources on a steel plate and tube. Source location results certified high robustness of suggested approach. Certain disadvantage of the new method is requirement of detailed scanning of region around a presumed source. Scanning may be eliminated if we use numerical simulations with TR signals put into a computer model of the structure. Localization accuracy of suggested procedure (approx. 1 mm) is better than the wavelength and transducers aperture.
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