Papers by František Fojtík
[Contribution to the replacement of the esophagus in children]
PubMed, Sep 1, 1968
[Roentgenological picture of pseudocysts of pancreas in children (author's transl)]
PubMed, May 1, 1978
[Traumatic Lung Changes Following Closed Thoracic Injuries]
PubMed, Mar 1, 1964
Proceedings of the 12th International Joint Conference on Biomedical Engineering Systems and Technologies, 2019
Dialysis sets are part of the dialysis circuit and are used every day. It is important to find ou... more Dialysis sets are part of the dialysis circuit and are used every day. It is important to find out how the dialysis sets behave under load and whether they retain their typical properties, which are the strength and flexibility. Therefore, the mechanical properties of the dialysis sets are evaluated depending on the selected physical parameters. For this reason, the sets are subject to temperature changes and changes in the pressure of the peristaltic pump occlusion cylinders. To evaluate the mechanical properties of the dialysis sets, the sets were subjected to stress tests and subsequent tests. The results were processed and analysed.
[Contribution to infravesical obstruction in children]
Rozhledy v chirurgii : měsíčník Československé chirurgické společnosti, 1967
[Our experience with the treatment of epiphysiolysis in the talar region (author's transl)]
PubMed, Dec 1, 1980
Applied and Computational Mechanics, Dec 17, 2009
This contribution describes the application of Fuxa's conjugated strength criterion on the experi... more This contribution describes the application of Fuxa's conjugated strength criterion on the experimental results under combined loading of specimens made from common construction steel 11523.0, melt T31052. The specimens were stepwise loaded by the torque amplitude, combination of torque amplitude and tension pre-stress, further by the amplitude of the torque in combination with inner overpressure and axial tension force. The last set of specimens was loaded by the torque amplitude in combination with inner and external overpressure and with axial tension force. To obtain the data required as the input values for the conjugated criterion the stress/strain analysis of the specimens by the finite element method in software ANSYS was performed. The experiments were performed on modified testing machine equipped by overpressure chamber.
MM Science Journal, Mar 3, 2010
Residual stress diffraction measurements in a thin surface layer are completely nondestructive. F... more Residual stress diffraction measurements in a thin surface layer are completely nondestructive. For subsurface stress profiling, the destructive X-ray analysis can be performed by sequentially removing surface layers by using electrolytic or chemical polishing. When stressed layers are removed, the measured stress values in depths beneath the surface are in general affected by the relaxation created due to the layer removal. Therefore a correction should be involved in the depth profiling procedure. Accepted procedures used till now presume the removal of the whole surface of the investigated laboratory samples. The aim of the contribution is to present the possibilities of FEM for evaluation of the credibility of X-ray stress-strain states measurements. An estimation of changes of depth distribution due to the stress relaxation created by the removed layers was simulated by FEM in the case of a small electrolytically polished area 12 mm in diameter in the middle of cylindrical samples of the height of 7 mm.
Acta Mechanica Slovaca, Mar 31, 2011
The paper describes the experimental results for the combined loading of the specimen manufacture... more The paper describes the experimental results for the combined loading of the specimen manufactured from the construction steel 11523, melt T31052. The first set of the specimen was loaded by the alternating torque amplitude. The second and third set of specimen was loaded by the combination of the bending moment and of the torque for two slants of 30 and 60 degrees in the conditions of the alternating cycle. The fourth set was loaded by the alternating amplitude of the bending moment. The conjugated strength criterion was applied on the experimental results. Further, new approximation based on the same boundary conditions as the described conjugated strength criterion was proposed. The required input parameters for the conjugated strength criterion were obtained from the stress-strain analysis of the specimen by the finite element method. Článek popisuje výsledky experimentů při kombinovaném zatěžování zkušebních vzorků vyrobených z konstrukční oceli 11523, tavba T31052. První sada zkušebních vzorků byla zatěžovaná střídavou amplitudou krouticího momentu. Druhá a třetí sada zkušebních vzorků byla namáhaná kombinací ohybu a krutu, pro dva úhly sklonu 30° a 60° v podmínkách střídavého cyklu. Čtvrtá sada vzorků byla zatěžována střídavou amplitudou ohybového momentu. Na výsledky experimentů bylo aplikováno konjugované kritérium pevnosti. Dále byla navržena nová aproximace, která vychází ze stejných okrajových podmínek jako popsané konjugované kritérium pevnosti. Pro získání potřebných vstupních hodnot do konjugovaného kriteria pevnosti byla počítána napěťově deformační analýza zkušebních vzorků metodou konečných prvků.
[Our experience with the treatment of epiphysiolysis in the talar region (author's transl)]
Acta chirurgiae orthopaedicae et traumatologiae Cechoslovaca, 1980
Notched structural steel specimens assessed by selected fatigue analysis methods
Journal of constructional steel research, Aug 1, 2024
Fretting Fatigue of 42crmo4+Qt Steel: Experimental and Numerical Assessment
This contribution describes experimental results under combined loading of specimens manufactured... more This contribution describes experimental results under combined loading of specimens manufactured from common construction steel 11523. Specimens were gradually loaded by amplitude of the torque, then by combination of torque and tension prestress. The last set of specimens was loaded in combination of torque and inner overpressure. To obtain the required input values the stress-strain analysis of specimens by finite element method in software Ansys was performed within the last experiment. For evaluation of the results the Fuxa's criterion was applied. The performed experiments and their results embody a good agreement with bellow mentioned conjugated strength criterion. The experiments were performed on reconstructed testing machine equipped by pressure chamber.
Sborník vědeckých prací Vysoké školy báňské-Technické univerzity Ostrava, Dec 30, 2013
The paper describes the experimental results obtained for the combined loading of the specimens i... more The paper describes the experimental results obtained for the combined loading of the specimens in the region of high-cycle fatigue. The specimens were manufactured from common structural steel 11523.1. There has been realized a set of proportional and non-proportional experiments in the area of high-cycle fatigue for basic methods of loading, namely: tension/compression, bending and torsion and its mutual combinations. By selected experiments, the specimens were additionally loaded by constant inner/outer pressure and axial prestress for a various loading levels. Experiments were realized on testing machines, situated at author´s workplace. The experimental results were undergone to application of selected and known criteria of fatigue strength and subsequently carried out its modification according to the results. For gaining necessary input values for criteria of fatigue strength, there was a need to realize a FEM simulation of test specimens. Článek popisuje výsledky experimentů při kombinovaném zatěžování zkušebních vzorků v oblasti vysokocyklové únavy. Použité zkušební vzorky byly vyrobeny z běžné konstrukční oceli 11523.1. Byla provedena sada proporcionálních a neproporcionálních experimentů v oblasti vysokocyklové únavy pro základní způsoby zatěžování tahem/tlakem, ohybem a krutem a jejich vzájemnými kombinacemi. U vybraných experimentů byly zkušební vzorky navíc zatěžovány konstantním vnitřním, vnějším přetlakem a osovým předpětím pro různé hladiny zatížení. Experimenty byly realizovány na zkušebních zařízeních nacházejících se na pracovišti autora. Na výsledky experimentů byly aplikovány vybraná a známá kritéria únavové pevnosti, a provedena jejích modifikace. Pro získání potřebných vstupních hodnot kritérií pevnosti byla provedena napěťově deformační analýza zkušebních vzorků metodou konečných prvků.
Transverse Cracking Signal Characterization in CFRP Laminates using Modal Acoustic Emission and Digital Image Correlation Techniques
Composites science and technology, Jun 1, 2024
DOAJ (DOAJ: Directory of Open Access Journals), Dec 1, 2010
The contribution describes the experimental results obtained from the combined loading of the spe... more The contribution describes the experimental results obtained from the combined loading of the specimens in the field of high-cycle fatigue. Those specimens were manufactured from common construction steel 11523.1, melt T31052. The following experiments were performed: The first set of the specimen was loaded by the alternating bending amplitude. The second set was loaded by the amplitude of the bending in combination with constant inner overpressure. The results were evaluated by the conjugated strength criterion and another generally used multiaxial fatigue criteria. The stress-strain analysis of the specimens by FEM was performed to determine parameters (constants) of particular strength criteria.
MM Science Journal
The article deals with the design of the technology of production of polyurethane foam (PU) speci... more The article deals with the design of the technology of production of polyurethane foam (PU) specimens and with their mechanical testing. A simple procedure is proposed to produce specimens with complex shapes. The procedure is tested on two different mounting foams. These specimens were subjected to several experiments. The article presents experimental results for only one mounting foam. The tests were performed on a Testometric M500-50CT testing machine. Specifically, these are a tensile/compression test, a 3-point bending test, a shear test, and a modified indentation test. For each specimen, the displacement was also measured in the selected area with Digital Image Correlation Method. These measured data are presented in the article.
Návrh zkušebního stroje pro stanovení závislosti intenzity napětí na intenzitě deformace ze zkoušky kroucením
Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta strojní. Katedra (... more Import 20/04/2006Prezenční výpůjčkaVŠB - Technická univerzita Ostrava. Fakulta strojní. Katedra (339) pružnosti a pevnost
Tensile Test on Samples Produced by Rapid Prototyping Technology with a Higher Number of Contours
2018 IEEE 22nd International Conference on Intelligent Engineering Systems (INES), 2018
The Department of Robotics has been long-term involved in application of technology Rapid Prototy... more The Department of Robotics has been long-term involved in application of technology Rapid Prototyping in projects primarily implemented in the area of mobile robotics. This relates to the issue of a correctly performed design of a model in the design phase. This requires the knowledge of material properties and the possibilities of working with the designed part in 3D printer software so that the required result achieves the best possible parameters with respect to the considered use. The paper deals with the possibility of improving mechanical properties in parts produced technology Rapid Prototyping technology. Based on results measured in a different area, a proposition has been stated which anticipates that an increase of the number of contours in mechanically stressed parts can lead to better mechanical properties. The proposition has been verified in mechanical tensile tests.
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Papers by František Fojtík