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Posouzení pevnosti lepení při nastavování překližovaných materiálů
Krejčíř, Michal
This master thesis is focused on mechanical properties of glued scarf for long-grain plywood extension made by request of company Orlimex CZ s.r.o. Main goal was to find out best type of joint and glue for this purpose and compare strength prop-erties of scarf jointed plywood versus non-jointed plywood. The reason for scarf-jointing plywood is the production on custom sized and non-standard panels as well as evaluating panel´s quality and possible application of cut off boards. All plywood properties were tested according to CSN EN terms and evaluated by statistics and cut analysis
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Loss of strength during welding aluminous alloys AW 6060
Sklenář, Martin ; Vaněk, Mojmír (referee) ; Sigmund, Marian (advisor)
The aim of the bachelor thesis is to qualify the welding procedure according to the standard ČSN EN ISO 15614-2. At the beginning of the work is introduced a company with which was this thesis made. This is followed by an assessment of the issue of aluminum. Furthermore, the mechanical properties of aluminum are discussed. Follows by part about welding specially about aluminium welding. In the practical part the samples were welded and subsequently evaluated, then the design and qualification of the welding process was made. In conclusion, the possibilities and results that have been achieved are summarized.
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Vliv vlhkosti na konvenční pevnost v tlaku podél vláken při roztlačování čelistí ve vývrtu
Pilát, Jaroslav
This final thesis deals with determination of moisture influence on convential strength pressure with use of the prototype diagnostic tool. This device can be used for in situ measurement of inbuilt wood properties in constructions. This new approach enables to determine strength and stiffness parameters of wood parallel to grain based on measurement of force required for pushing jaws inside the predrilled hole apart. The thesis aim is to determine the mechanical properties of wood by both experimental testing of novel device and with universal testing machine. The results of experiments are mutually compared, statically evaluated and also compared with known values. The experiments are carried out according to the standards for testing of the mechanical properties of raw wood
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Stanovení mechanických charakteristik kořenů
Bujok, Lukáš
This bachelor deals with describing and assessmenting basic mechanical properties of woot-roots. Experimental determination of mechanical properties was carried out by the destructive method roots tensile stress on test machine. Test was carred out on three tree species. : Norway spruce (Picea abies (L.) Karsten), Black poplar (Populus nigra L.) and Silver birch (Betula pendula L.). In the first place designed suitable method for testing wood-root. The thesis furthure describes the process of obtaining and preparation of sample, procedures during the actual testing, statistical analysis, comparing with the literature and discuss the impact of factors on the results achieved. The results indicate a statistically significant difference between the modulus of elasticity of birch and data spruce and poplar, data tensile strength of birch and data of spruce and poplar, failure force of poplar and spruce, data relative deformation on tensile strength of all the data together, data toughness poplar and data spruce and birch. Statistically insignificant was impact diameter of the root in poplar and spruce on the elastic modulus and the same applies of tensile strength, further we failed to demonstrate the influence of the diameter of the chimney to deformation at the roots of spruce and birch.
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Analýza mechanických vlastností kolíčníků piana
Zatloukal, Petr
This work focuses on the analysis of the mechanical properties of piano pin blocks. Three pin block types were used, all made from multi-layered beech-plywood. Pin block were divided to eight sections, drilled and fitted by tuning pins. Tightening torque of tuning pins was measured using a torque wrench, depending on the diameter of the hole. Mechanical resistance of the material was measured by microdrill Resistograph. Density distribution in pin blocks and moisture content were determined with gravimetric method. The universal testing machine was used for determination of Janky's and Brinell's hardness, the mechanical properties in compression in plane of the board. Results of tests were evaluated using statistical methods and cross-correlated. A finite-element model in ANSYS software was built, in ordner to clarify the degree and distribution of stress around the hole for tuning pin. Statistically significant differences were found for properties of individual types of pin blocks (especially the density, hardness and compressive strength and tightening torque). Hardness differs significantly when tested perpendicular to the fibers in the plane and along the fibers in the edge. Measurements in individual sections of pin block brought uneven results and did not show statistically significant differences. Significant correlation was found only between the folowing characteristic: type A: the density distribution and the mechanical properties of the plane, density distribution and tightening torque after loosening. Type B: Resistograph resistance and tightening torque after 14 days, the density distribution and mechanical properties of the plane. Type C: density distribution and tightening torque after driving and loosening. Accurate results would be achieved by multiple measurements on multiple pieces of the pin blocks.
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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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Srovnání stavby a vybraných vlastností dřeva douglasky tisolisté z různých stanovišť
Timko, Lukáš
The aim of this thesis was to analyse the macroscopic structure of the wood of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and determine selected physical and mechanical properties with an emphasis on the comparison of juvenile and mature wood zones. Additionally, the structure and selected properties of the wood from sites varying in the forest types (3K, 3B, 3A) were compared. Five sample trees were sampled in each of the three selected sites. Their rootstock parts were then worked into test specimens with dimensions of 20 x 20 x 30 mm a 20 x 20 x 300 mm. The selected wood properties were the density at moisture content of 0% and 12%, basic density, the total shrinkage in all three basic directions, the total volumetric shrinkage, strength in compression parallel to the grain, bending strength, and the modulus of elasticity in bending. Additionally, a tree-ring analysis was conducted. It was found out that the juvenile wood has wider rings, a lower proportion of earlywood and all the observed properties showed lower values. The properties determined and the structure of the wood from the selected groups of forest types is statistically significantly different in most cases. From the forestry perspective, the resulting material characteristics of wood of Douglas fir are greatly dependent on the site; however, the precise location of the sample within the stem (centre or periphery) has a more pronounced effect on the properties.
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Slisovatelnost dýh pro použití ve vrstvených lepených materiálech
Krejčíř, Michal
This bachelor work is based on studies of physical and mechanical properties of plywoods with various composition. The goal of research was to determine the influence of pre-pressed beech veneer on bending properties. There is also review of plywoods manufacturing in the work. The properties of plywood were tested according to EN standards and evalueted by descriptive statistics and Analysis of variance.
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Analýza mechanických vlastností balzového dřeva na mesoúrovni pomocí zkušebního stroje iErudio
Grossová, Olga
This thesis analysis the mechanical properties of balsa wood mesolevel using the test machine iErudio. The thesis aim is to experimentally determine the mechanical properties of balsa wood (Ochroma lagopus). On the prototype minimachine iErudio is a set of measurements. Specifically, tensile and bending tests. Another objective is to determine the Poisson ratio on measured levels. These properties will be obtained from image data recorded device iErudio and calculated using the digital image correlation. Another objective is to evaluate the work done with the prototype device, point out the advantages and disadvantages. To analyse data using a commercial computer program VIC 3D and Mercury RT, which process the results using digital image correlation. The work has provided us with confirmation of mechanical characteristics of balsa and the suitability of using "minimachine" iErudio the performed tests.
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