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Effect of strain rate on the mechanical properties of materials
Gajdošík, Matej ; Forejt, Milan (referee) ; Jopek, Miroslav (advisor)
Metóda Taylorovho testu je využívaná na skúmanie vlastností materiálu za podmienok dynamického zaťažovania. Práca predstavuje kompletný proces vývoja, montáže a testovania nového testovacieho zariadenia zameraného na dosiahnutie symetrického nárazu dvoch vzoriek materiálu v pohybe. Zariadenie je testované v dvoch konfiguráciách, pričom sú opísané výsledky oboch. Boli vykonané materiálové testy smrekového dreva, ktoré boli následne porovnané s výsledkami získanými z klasického Taylorovho kanóna. Boli zistené a opísané podstatné rozdiely. Ukázalo sa, že vykonané simulácie symetrického nárazu s využitím modelu smrekového materiálu nezodpovedajú praktickým experimentom, čo naznačuje potrebné zmeny modelu.
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Mechanical behaviour of Strenx steel at high strain rates
Basler, Matěj ; Forejt, Milan (referee) ; Jopek, Miroslav (advisor)
The thesis is focused on the description of the behaviour of high-strength steel Strenx under quasi-static and dynamic conditions with emphasis on the influence of anisotropy. A compression test was used as a low strain rate test with specimens formed from rolled sheet in the 0, 45 and 90 degree directions relative to the rolling direction. The behaviour of the steel at high strain rates was described using the Taylor impact test, again with specimens oriented with respect to the rolling direction. The contour of the deformed specimens from the dynamic test was measured by image analysis and the dynamic yield strength of Strenx steel was calculated. The test results were compared between the loaded directions and the anisotropic behaviour of the material was described. From the values obtained from the performed experiments, the material constants for Johnson-Cook's material model were determined and its reliability was compared with both quasi-static and dynamic test results. The calculated values using the material model achieved satisfactory accuracy and the developed material model can be considered reliable.
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Development of a test specimen carrier for a symmetrical impact test
Hoffman, Petr ; Forejt, Milan (referee) ; Jopek, Miroslav (advisor)
The thesis focuses on the development and optimization of a wooden specimen carrier for the symmetric Taylor test. It includes a detailed description of dynamic material tests, internal ballistics of the projectile, and labyrinth seal. The thesis summarizes the history of the carrier development for the Taylor test and analyzes its current state. A new carrier for the symmetric Taylor test and wooden specimens with a square cross-section was developed. Using simulations and tensile tests, the ultimate strength for the given carrier was determined. Subsequently, the thesis addresses the design and impact of the labyrinth seal on the carrier's velocity, which was designed based on simulations in the ANSYS program and practically tested in the Taylor test
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Production of socket wrench
Kryštof, Marek ; Forejt, Milan (referee) ; Císařová, Michaela (advisor)
This thesis propses the design of production of a socket wrench. A socket wrench is used as safety wrench for loosening safety screws of the car wheels. The proper technology for production was chosen based on the component requirements. The component is made by using metal extrusion and heading. The starting blank for metal forming was chosen steel rod made of 1.7131 steel (ČSN 14 220) with a diameter of 26 milimeters. The safety wrench will be made by doublecrank press GTX-300H. Production will be done in three operations.
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Production of filter cover
Bachurek, David ; Forejt, Milan (referee) ; Podaný, Kamil (advisor)
The project elaborated design of technology production of the filter cover - section from the deep drawing sheet 11 325 (DC04). Based on analysis was chosen combination of technologies shearing and deep drawing for that option was designed manufacturing process. Forming process is realized on hydraulic progressive press from Sweden company AP&T which has got total nominal tensile force 1740 kN and equipped 5 stations with lower holders and upper ejectors. Deep drawn part is transported between stations by feeders which are part of press. Function parts are made from alloyed tool steels 19 436 and 19 573 which are heat-worked according to drawing documentation. In chapter technical and economical evaluation was determined turning point which become after reaching of 142 840 parts.
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Evaluation of materials characteristics exploiting static and dynamical tests
Riesner, Jan ; Forejt, Milan (referee) ; Samek, Radko (advisor)
The project elaborated in frame of engineering studies branch M-STG describe characteristics of plasticity of non-anneal materials E 235, E 190 and E 220. Materials characteristic was receive by static and dynamical tests. Based on the literature study it was conducted survey of the current state of experimental techniques for high-speed deformation. The materials were designed by Holomon approximation of rigid-plastic material model without hardening. It was conducted force analyses for machine Unison MG 2790 for rewind bending and bend with compressive force considering the identified material model. It was describe the impact passive and active forces to move the neutral axis.
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Producing of artillery shell
Moravec, Zdeněk ; Forejt, Milan (referee) ; Lidmila, Zdeněk (advisor)
The diploma thesis deals with the technology of production of the body of an artillery shell caliber 155 mm from C60 steel. The part is manufactured in series of 100,000 pieces. Based on a literature study and materials, a technological procedure of drop forging was designed, taking into account the specific shape of the forging. The volume of the starting blank and the forming force were determined. A suitable forming machine was selected based on the magnitude of the forming force. The design of tools for punching operations and reduction diameters of sets of rollers for forging stretching was also performed. In the technical and economic evaluation, the material costs for the production of the entire series were quantified.
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Production of short shaft by extrusion
Hondl, Jiří ; Šlais, Miroslav (referee) ; Forejt, Milan (advisor)
HONDL Jiří: Production of short shaft by extrusion. The project prepared as part of the Master-degree studies in the Engineering technology concerns the technology design for manufacturing a short shaft by extrusion. On the basis of the study cold forming methods and problems and following technical calculations was designed a four steps process of forming. Semifinished product has a cylinder shape with a diameter of 18mm and a length of 51,2mm. The production is designed for automatic multistage press TPZK 25 with nominal pressing force of 5 000kN from Czech producer and supplier of machinery Šmeral Brno company. Tools are made of tool steel, extrusion punch and extrusion die is designed of 19 830.4 steel, and extrusion die´s band is designed of 19 733.4 steel. Tools are designed to be improved by hardening and drawing.
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Forming technology production of ending of brake hose
Obůrka, Miloš ; Šlais, Miroslav (referee) ; Forejt, Milan (advisor)
The purpose of the diploma thesis elaborated during studies of Engineering technology is to project the technological process for production of brake hose end made of 12010.3 steel by cold forming. Based on the study of the cold forming problems and following technical calculations of the production process was designed a 3 steps process of forming. As a semiproduct was chosen wire stub with a diameter of 11.2 mm and a length of 27mm. The production is designed for automatic multistage press TPZK 25 from local manufacturers Šmeral Brno, a.s.
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Bulk forming technology of carrier pin
Večeřa, Jiří ; Samek, Radko (referee) ; Forejt, Milan (advisor)
This thesis deals with a proposal of a technology for manufacturing a carrier pin made of corrosion resistant chrome steel 17 021.3. Having studied the information about cold bulk-metal forming in the available literature, I have suggested two variants of manufacturing processes. The suggested manufacturing variants consist of four forming operations which combine upsetting and extrusion. As far as the chosen variant is concerned, there have been made technological and strength calculations for the individual operations. As regards the designed technology, I have opted for the automatic multistation forming machine TPZK 25, produced by the company ŠMERAL Brno.
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