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Vliv chemické modifikace na vybrané vlastnosti dřevěné pružiny
Novák, Filip
This thesis focuses on the influence of chemical modification on a wooden spring.The spring was made of beech wood (Fagus sylvatica, L.). Bending ratio was chosen 1:4 thickness to radius. The effectiveness of the chemical modification with acetic anhydride was measured by weight percentage gain (WPG). Acetylation was made with 18 % WPG (at full acetylation 25 % WPG was observed damage of bent wood mostly by compression stress). Chosen spring properties was evaluated in four moisture states (dry, in condition of 65 %, 85 % and 99 % relative humidity and temperature 20 °C). Influence of acetylation on mechanical properties was proven. In wet condition acetylated samples proved higher shear modulus of elasticity a higher rigidity of spring. In dry condition acetylated samples proved lower shear modulus of elasticity a lower rigidity of spring. Influence of acetylation on dimension stability was proven. Acetylated samples proved reduction of equilibrium moisture content (46-56 %) in comparison to reference samples. Acetylated samples proved swelling reduction in radial direction (41-56 %) and in tengential direction (46-59 %). More regular swelling (ratio of radial and rangential) was observed at acetylated samples. Influence of acetylation on shape stability was proven. Shape stability of acetylated spring was evaluated by change in diameter of spring in different moisture states. Wet conditions caused enlargement of acetylated spring diameter (5-16 %) and of reference spring diameter (10-40 %). Reduction of shape changes was observed (57-75 %).
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Židle z ohýbaného dřeva firmy Thonet
Kábelová, Aneta
The bachelor work deals with the history and the development of the Thonet Company. It describes the particular phases of the company from the first workshop in Vienna to the present day joint-stock company TON. A list of the most important parts of sitting furniture with a brief description and photographs is a part of the work. The work describes in detail one particular chair from Michael Thonet, chair 6009. The photographs of the chair with a technical description are enclosed. I also enclose the view of the historical development and the survey of both public and private interiors in which the chair appeared or appears. The information gained is further used for my own design of a public interior, a small-town café. The design includes the ground plan made in the program AutoCAD 2012 and visualizations in the program 3ds Max Studio 2015.
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Vliv chemické modifikace na rozměrovou stabilitu ohnutých dílců z masivního bukového dřeva
Jacko, Ondřej
This thesis deals with the effect of chemical modification on dimensional stability of bent solid beech wood samples. Acetylation at 120 ° C and steaming in saturated steam at 90 °C were chosen as chemical modification. The properties examined included dimensional stability and moisture absorption of the bent specimens. Standard samples produced were used to determine properties such as bulk swelling, moisture absorption and density. These properties were determined after modification, after long-term storage in a warehouse and after storage in an climate chamber at 20 ° C and 80% relative humidity. The air conditioning was followed by drying the bent samples to 0% humidity, which showed the dimensional stability of the bent shape. The best weight percent gain (WPG) values were achieved by standard and bent acetylated samples, the AC 2 group, which also had the most reduced RVD. The WPG for this group was 23.31%. Due to the highest WPG value, this group also achieved the best values in detecting anti-swelling efficiency (ASE), ie 81.99%. The best dimensional stability was achieved by steaming the specimens in saturated steam
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Využití mikrovlnné plastifikace dřeva při výrobě ohýbaných nábytkových dílců
Nováčková, Kateřina
This bachelor thesis is dealing with microwave plasticization for wood shaping and its potential utilization in furniture industry. European beech (Fagus sylvatica L.) specimens of dimensions 20 × 20 × 300 mm were sorted into 8 groups (each group consisted 15 specimens). Reference specimens (Ref1) were tested as oven-dried at room temperature, furthermore reference specimens (Ref2) were tested as oven-dried at 80 °C and last reference group (Ref3) was conditioned to fiber saturation point (FSP). Specimens of conventional, steam plasticization (Vp) were conditioned to FSP and heated at 100 °C for 1 hour. Microwave plasticization was carried out at 1,5 and 3,5 kW using continuous laboratory MW device All MW specimens were soaked in water in order to reach approx. 60 % of MC.Output moisture content (MC) of MW treated specimens was 20 % (MW1), 30 % (MW2, MW4) and 40 % (MW3). Moreover, additional specimens of dimensions 30 × 30 × 450 mm were used to up-scale its possibilities of use. These specimens were sorted into 2 groups (Ref and MW), each group consited 20 specimens. Effect of plasticization was measured by means of static 3-point bending test. Plasticity of wood was evaluated by modulus of elasticity (MOE), modulus of rupture (MOR) and deflection. Results of reference specimens confirmed influence of temperature and moisture content on MOE and MOR. Influence of moisture content (0 % and FSP) was found to be more significant and 65 % decrease of strength MOR and 40 % of MOE is reported. Steam plasticization, as a conventionally used method for shaping, led to increase of plasticity (decrease of MOE about 65 %) and deflection (70 %) when compared to Ref1. Significantly higher deflection (up to 1,5 mm) and increase of plasticity (MOE decreased about 72 %) was found for specimens plasticized by MW at 1,5 kW and 3,5 kW from initial moisture 60 % to output moisture 30 %. Based on results, it can be stated that microwave technology have similar effects on wood plasticity, when compared to conventional method wood plasticization – steaming. Results of present thesis confirmed high potential of MW plasticization for wood shaping. Reduction of time and safe energy might be considered as a great advantage for furniture production. Futher studies should be done in future in order to reveal effect of MW on structural changes, eventually to optimize process for specific shapes.
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Židle z ohýbaného dřeva firmy Thonet
Kábelová, Aneta
The bachelor work deals with the history and the development of the Thonet Company. It describes the particular phases of the company from the first workshop in Vienna to the present day joint-stock company TON. A list of the most important parts of sitting furniture with a brief description and photographs is a part of the work. The work describes in detail one particular chair from Michael Thonet, chair 6009. The photographs of the chair with a technical description are enclosed. I also enclose the view of the historical development and the survey of both public and private interiors in which the chair appeared or appears. The information gained is further used for my own design of a public interior, a small-town café. The design includes the ground plan made in the program AutoCAD 2012 and visualizations in the program 3ds Max Studio 2015.
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