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The study of adhesion of glued balistic composites on the dependence of materials used.
Dobiáš, Jiří ; Másilko, Jiří (referee) ; Šiler, Pavel (advisor)
The aim of this work was to investigate the properties of bonded ballistic materialsBalistic composites are mainly glued to reduce weight while keeping their protective properties. On this basis, the materials used were ballistic steel, ceramics, rubber kevlar, non-gummed kevlar, Dyneema and fiberglass. For bonding used were a one-component adhesive Collano 36.104 and two-component adhesive Biresin U1305. The strength of the joint was measured in shear at tensile loads. From these results, deformation energy was further calculated.
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Evaluation of load-deformation characteristics of glued timber using DIC analysis
Šot, Michal ; Vejpustek,, Zdeněk (referee) ; Vaněrek, Jan (advisor)
The work deals with issues of evaluation of the shear properties of timber structural materials, particularly CLT elements. The work contains an overview of extensive research so far presented scientific studies dealing with the characteristic shear properties of wood. In the practical part was carried out the experiment dealing with the failure mode of transverse lamellae of CLT elements that were exposed to shear stress. There were observed individual effects that this may affect the material properties. In the first part of the experiment were performed numerical models using FEM. In the second part, the test specimens were tested in three point bending. Here, attention was paid to the influence of macroscopic properties of wood on the distribution of stress cracks and shear strength, the tests were recorded using DIC system.
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Machanical testing of solder joints
Drab, Tomáš ; Šandera, Josef (referee) ; Szendiuch, Ivan (advisor)
The project contains theoretical research of electrotechnical manufacture for lead-free reflow soldering. It contains characterization of soldering processes. Includes variations of solder paste printing, principles of part placing and also reflow soldering process. The project appoints possibilities of testing solder joints strength, mainly focused on mechanical vibrations. It describes a design and preparation of solder joint strength test methods by mechanical vibrations. It compares influence of vibrations on part types and solder alloys.
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Experimental comparison of shear properties of FRP measured by ASTM methods
Ponížil, Tomáš ; Mališ, Michal (referee) ; Urík, Tomáš (advisor)
Přesné určení konstitutivních smykových závislostí napětí na deformacích je základem pro pochopení chování anizotropního kompozitního materiálu. Bylo vyvinuto mnoho zkoušek smykových vlastností kompozitních materiálu. Jelikož vyvolání čisté smykové napjatosti je složité, tento stav je vyvolán pouze některými z nich. V této práci je ověřeno použití systému Aramis k vyhodnocení průběhu smykového přetvoření a následnému výpočtu konstitutivních smykových vlastností při provedení jednoduché zkoušky ohybem krátkého nosníku. Tyto výsledky jsou dále porovnány se zkouškou podle Nicolae Iosipesca.
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Shear strength of sand under very low normal load
Hudek, J. ; Koudelka, Petr
Solutions of some extraordinary geotechnical problems need knowledge of shear strength in a scale of very low normal stress. An example is physical modelling of soil mass behaviour using medium or little samples. The paper deals with results of testing a very dry uniform quartz sand of medium size. Resulting values of effective shear strength for the normal stress scale till of 25 kPa are compared with former testing of the same material in other scale of 63 – 163 kPa.
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