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Possibilities of using 4D computed tomography in fracture tests
Kumpová, Ivana ; Fíla, Tomáš ; Koudelka, Petr ; Rozsypalová, I. ; Keršner, Z. ; Kytýř, Daniel ; Vopálenský, Michal ; Vavřík, Daniel ; Vyhlídal, M. ; Drdácký, Miloš
The paper presents the study of the internal structure and fracture properties of selected quasi-brittle building materials subjected to temperature changes and the possibility of applying the method combining bending fracture tests and time-dependent computed tomography (4D CT). The tested specimens were subjected to hightemperature effects and subsequently tested by a four-point bending during 4D CT. Thus, 3D image information was obtained in different phases of loading and material damage. Comparative compression strength measurements were also performed. These results are in good agreement
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Large-area scans of paintings with high resolution
Vopálenský, Michal ; Kumpová, Ivana
The aim of the measurement was to obtain the radiographs from historical paintings from the Faculty of Restoration of the University Pardubice. Due to the dimensions of the paintings (up to 90 x 110 cm) it was necessary to develop a suitable measurement procedure for successive scanning of the paintings in the TORATOM device. The resulting data are important for the planning of the restoration processes of the paintings and can help to discover otherwise invisible details, like underpaintings etc.
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Historical lingerie: 18th century corset
Kumpová, Ivana ; Vopálenský, Michal
The work was focused on the methodology using X-ray tomographical imaging for the exploration of the textile-based historical artifacts. The 18th-century corset was investigated by this method. The inspection was conducted to reveal the production technology, design solution, decoration and possible damage in the front area where the whalebones converge. The computed tomography performed on the TORATOM device enabled visualisation of the internal structure of the area of interest with high precision. Sewing details and details of the composition of different material layers are well visible. Fractures and frayed ends of the whalebones were observed. In the area of interest, it is possible to distinguish several materials used for padding of the plastic parts.
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Instrumentation of four-point bending test during 4D computed tomography
Kytýř, Daniel ; Fíla, Tomáš ; Koudelka_ml., Petr ; Kumpová, Ivana ; Vopálenský, Michal ; Vavro, Leona ; Vavro, Martin
High-resolution time-lapse micro-focus X-ray computed tomography is an effective method for investigation of deformation processes on volumetric basis including fracture propagation characteristics of non-homogeneous materials subjected to mechanical loading. This experimental method requires implementation of specifically designed loading devices to X-ray imaging setups. In case of bending tests, our background research showed that no commercial solution allowing for reliable investigation of so called fracture process zone in quasi-brittle materials is currently available. Thus, this paper is focused on description of recently developed in-situ four-point bending loading device and its instrumentation for testing of quasi-brittle materials. Proof of concept together with the pilot experiments were successfully performed in a CT scanner TORATOM. Based on results of the pilot experiments, we demonstrate that crack development and propagation in a quasi-brittle material can be successfully observed in 3D using high resolution 4D micro-CT under loading.
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Utilization of image and signal processing techniques for assessment of built heritage condition
Koudelka_ml., Petr ; Koudelková, Veronika ; Doktor, Tomáš ; Kumpová, Ivana ; Kytýř, Daniel ; Valach, Jaroslav
Historical buildings represent invaluable heritage from the past and therefore their protection is a very important task. Assessment of their condition must not cause damage accumulation thus the least possible volume removed from the structure is essential. As many historical buildings in the Czech Republic are built using sandstone that can be considered as a typical heterogeneous system, statistical signal processing is a promising approach for determination of the representative volume element (RVE) dimensions. Such calculations can be carried out on the domain of logical arrays representing binary images of the materials microstructure. This paper deals with processing of image data obtained using SEM-BSE and high resolution flatbed scanner for determination of RVE dimensions. Advanced image processing techniques are employed and results from calculation using grayscale data are presented and compared with results calculated on the basis of color input images.
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Analysis of Baroque sculpture based on X-ray fluorescence imaging and X-ray\ncomputed tomography data fusion
Vavřík, Daniel ; Kumpová, Ivana ; Vopálenský, Michal ; Lauterkranc, J.
It is advantageous to combine information about geometry and the inner structure of historical artifacts with information about the elemental composition of decorative layers, typically covering historical wooden sculptures. X-ray computed tomography describing artifact structure is quite common and easy. Standard X-ray fluorescence (XRF) analysis of decorative layers is typically done for several selected spots of the artifact’s surface utilizing single pad detector. XRF imaging fully describing the surface’s elemental composition is commonly done for flat objects, while time consuming XRF tomography is applied to relatively small objects. It will be shown in this work that an effective fusion combination of XRF imaging and X-ray tomography describing the whole object can be realized even when using a limited number of XRF images.
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Optimization of acquisition parameters in radiography and tomography
Vopálenský, Michal ; Vavřík, Daniel ; Kumpová, Ivana
Contrast in radiographic images is one of the most important parameters both in radiography and tomography. This paper investigates the possibility of adjusting the radiographic parameters, in particular the accelerating voltage of the X-ray tube, in order to maximize the difference in the detected intensity in response to the change in the thickness of the investigated object. Simplified model is used that allows finding the optimal operating point for the given material and thickness without an apriory knowledge about the X-ray spectra, detector response and the material composition. It is shown that in case of small changes of thickness, the optimum is met when the detected intensity behind the object of certain thickness is at approx. 37 % of the full range (i.e., of the value that would be measured under the same conditions in the absence of the object). In spite of simplifications made, the theoretical model shows a very good correspondence with the experimental data. A brief consideration is made on the case of a general difference in thicknesses.
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Possibilities of using X ray tomography for description of damage of temperature loaded concrete
Rozsypalová, I. ; Kumpová, Ivana ; Daněk, P. ; Šimonová, H. ; Keršner, Z.
The effect of high temperatures on concrete affects the internal structure of this composite material. The paper opens the question of the possibility of using a computed X–ray tomography to quantify the degree of damage of a concrete specimen that was drilled from the selected experimental panel loaded in a fire furnace with high temperatures at the AdMaS (Advanced Materials, Structures and Technologies) research centre at Faculty of Civil Engineering Brno University of Technology. The nominal value of the maximum temperature on the heated side of the panel was 1000 °C. Advanced workstation computer X–ray tomography TORATOM at Centre of Excellence Telč (CET) is parallel imaging of an object in two spectra of X–ray radiation, that allows to highlight differences between the material components to the full X–ray spectrum similar to the attenuation of the radiation.
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