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Mechanical properties of the lamellae materials
Vokatý, Vojtěch ; Gaff, Milan (advisor) ; Babiak, Marian (referee)
This thesis evaluated experimental research on the influence of selected factors (species, thickness, density, number of stress cycles) on the specified material characteristics (modulus of elasticity, modulus of rupture, limit of proportionality, bendability coefficient). The measured values were statistically evaluated and expressed in tables and graphs. Beech (Fagus Sylvatica L.) was selected to represent hardwood and aspen (Populus Tremula L.) softwood.
Tree species affects all observed characteristics. The results show that the modulus of elasticity increases with increasing densification of the material, but decreases with the increasing thickness of the material. A similar dependence is observed even with the modulus of rupture and limit of proportionality, which is also dependent on the number of cycles. The bendability coefficient is affected by material thickness.
It is expected that based on the evaluation of the results it will be possible to design materials with tailored properties.
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Principles targeted Edit the properties of layered materials
Houžvíček, Petr ; Gaff, Milan (advisor) ; Gašparík, Miroslav (referee)
Target of the thesis was an investigation of the influence of selected factors (tree species, thickness of material, type of glue and cyclic loading) and their combinations on strength properties of laminated lumber. This measured properties were: bending strength, modulus of elasticity, limit of proportionality, coefficient of bendability and shear strength of glued joint.
Most important factor for bending strength, modulus of elasticity and limit of proportionality was the tree species. For coefficient of bendability and shear strength of glued joint the most important was the material thickness. Influence of cyclic loading and type of glue, weren´t proved.
After that, we simulated our investigation which we made in computer program based on finite element method. The simulation corresponded just for thicker tested samples.
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Mechanical design of stend for lower limbs prostheses dynamic testing
Taufer, Tomáš ; Robenek, Dětřich (referee) ; Paloušek, David (advisor)
This work describes design and realization of testing device for dynamic tests of foot prosthesis, made by methods of Rapid prototyping. Primary objective of design is to imitate the load on prosthesis during human gait. This task is accomplished by swing motion of prosthesis inside the frame of device during the loading of heel and tiptoe. Loading components can be removed and changed so the device can be used for different measurement like walking on an inclined plane. The result of this work is fully functional device including control program with many options to control the test. The result of test is to decide whether the foot prosthesis withstands the set of cyclic loads. The area of development of prosthesis by additive methods is young for the time being. It stands out especially with different materials, design, structure of prosthesis and fast process of production. Therefore this device can be used for testing of fatigue life of prosthesis made by additive methods.
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Test stand for testing of frame and fork of scooter
Kostka, Marek ; Klapka, Milan (referee) ; Brandejs, Jan (advisor)
The aim of this bachelor thesis is construction design of the testing station for tests of cyclical straining of the frame and fork of the footbike in loading by men in weight from 50 to 150 kg and in kick frequency from 10 to 120 kicks per minute. The format of this work is divided into four main parts. In the first part is this work orientated to actual demands of the footbike. In this part is also described construction design and solution of other testing stations. In other part of this work is accomplished analysis of powers which influent footbike and there are defined particular parameters for testing station. In the third part is described possible approach to solution of testing station and to particular contructional nodes. Last part of this work talks about the resulting proposal of constructional design of the testing station.
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