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Optimalizace měření rychlosti pulzní vlny v tepnách
Macková, H. ; Chlup, Hynek ; Hulan, M. ; Žitný, R.
Measurements of the pulse wave velocity (PWV) in human arteries are important for two different reasons: an early diagnostics of atherosclerosis and identification of material properties of the vessel wall for numerical simulations. The PWV in blood vessels is not constant and classical methods of pressure wave shift between two points are not sufficient. We consider three methods: optical measurements of vessel wall displacement in several points by high speed camera, continual optical measurements of vessel wall displacement by correlator Q-450 and measurements of flow rate and displacements by ultrasonic device. The first method can determine the PWV only between several points. The second method can show 3D reconstruction of displacements with very good resolution. The ultrasound measurements need combination of Doppler ultrasound velocimetry and B-scan imagining. However, the common devices used in medicine do not have any data output. It causes bad resolution.
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Experimental determination of stress-strain dependence of non-standard materials
Vavřík, Daniel ; Drdácký, Miloš
The subject of this work is experimental determination of mechanical properties for different types of animal hairs. Mortars reinforced by thin fibres have promising properties for application in cultural heritage protection. Theoretical research is based on mathematical modeling of composite materials with inorganic (brittle) matrix and differential types of reinforcement fibres - natural as well as man made polymeric fibres. For these models, knowledge of mechanical properties of the fibres is needed. Optical method developed especially from this purpose will be introduced in this paper.
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Evaluation of accuracy of steel plate girder initial imperfections measurement carried out by means of fringe projection method
Valach, Jaroslav
The method of fringe projection and its application to investigation of steel plate girders subjected to repeated loading is described in this contribution. The well known fact of decisive role of production-based girders imperfections on the girders period of service emphasizes the need of a reliable measurement method of the imperfections. The optical method described in this paper is based on determination of out-of-plane deviations by means of analysis of geometrical relations in the image of projected fringe pattern on the girder surface. The advantage of the method is its simplicity, scalable sensitivity and absence of any constrains regarding the size of the studied object. The results obtained using the method are compared to that attained by the existing method and their accuracy and time consumption is considered. Finally, applicability of the proposed method in other fields is discussed.
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