National Repository of Grey Literature 19 records found  1 - 10next  jump to record: Search took 0.01 seconds. 
Modification of inert atmosphere circuit of 3D printer SLM 280HL
Somora, Jakub ; Maňas, Pavel (referee) ; Koutný, Daniel (advisor)
The diploma thesis deals with the design modification of the circulation circuit of inert atmosphere in the 3D printer SLM 280HL. The aim of the proposed modifications was to increase the efficiency of condensate and flue gas removal and thus increase the quality of the production process. Based on experimental measurements of the velocity field at a height of 12 mm, it was found that in the original configuration of the build chamber, there are sites with reduced flow velocity. The test subsequently confirmed the increased porosity of the samples in the given localities. Subsequently, with the help of CFD simulations, a lower flow distributor was designed, which had the most significant effect on the porosity. Furthermore, an additional outlet and flow deflector were designed, which had the task of streamlining the drainage of condensate and fumes from under the protective glass of the laser. The designed components were manufactured and experimentally verified, which was able to prove the flow improvement and reduce the porosity on the platform. A test was also performed with a magnesium-based material, which proved more efficient removal of condensate and flue gases. The work managed to prove the influence of the flow velocity on the porosity of the component at differences in flow velocities above 0,3 ms^-1.
Numerical model of lattice structure under dynamic loading made by Selective Laser Melting technology
Červinek, Ondřej ; Maňas, Pavel (referee) ; Vrána, Radek (advisor)
For the purpose of mechanical impact energy absorption in the transport industry are mainly used special profile absorbers. For highly specialized applications is required to use components that are designed for specific kind of deformation. Example of these parts are industrial-made metal foams or micro-lattice structures produced by SLM technology. This paper focuses on low-velocity dynamic loading prediction of BCC micro-lattice structure made of aluminum alloy AlSi10Mg by SLM technology (SLM 280HL). For this purpose dynamic FEM simulaton of the micro-lattice structure was developed, supplemented by model of BCC structure material obtained from mechanical testing. Real geometry of tested samples obtained from optical measurement (Atos Triple Scan III) was further implemented in the numerical model. Dynamic BCC structure load experiment was performed on a drop-weight tester. Behavior of structured material in drop-weight test was described by the course of deformation and reaction forces over time. Comparable results were obtained for flat loading of dynamic FEM simulation and experiment. Inclusion of production phenomena in simulation led to increased accuracy and compliance with experiment. Tool for testing the effect of geometry change on mechanical properties was created. To achieve more accurate results with puncture load, it is necessary to modify the material model with real material deformation at test sample failure.
Design of cleaning unit of central impression cylinder for flexographic printing machine
Falta, Jan ; Maňas, Pavel (referee) ; Černohous, Pavel (advisor)
This master´s thesis is focused on design and manufacturing of prototype of central impression cylinder cleaning unit. This thesis contains explaining of basic principle of flexographic printing and preview of types of flexographic printing presses. There are explained patented cleaning units and main claims of every patented cleaning unit. In the next part of this thesis, there are some conceptual designs, from which was chosen the final design for manufacturing. In the next part of this work, there are detailly described each of the parts of cleaning unit. Prototype of the cleaning unit was manufactured and tested in the SOMA Engineering s.r.o. Lanškroun. Cleaning unit will simplify the work of operators and reduce time, needed to clean the central impression drum in comparison with manually cleaning.
Design of entrance ramp for handicapped people to city buses
Pospíšil, Luděk ; Maňas, Pavel (referee) ; Dvořáček, Jiří (advisor)
Diploma thesis deals with the design of the automatically controlled ramp for the boarding of physically disabled people in city buses. The initial research section deals with the regulations and directives that must be respected in the design, the issue of wheelchair mobility and the analysis of design considered elements. In the second part the thesis goes to the chosen design solution. The design input parameters are the height of the ramp cassette, the slope of the ramp when boarding and the width of the boarding platform. The platform is extended by a pair of pneumatic cylinders along with a scissor mechanism guided in a linear ball guide. The boarding platform is made of an aluminium honeycomb panel which strength is verified by analytical calculation. At the front edge, the boarding platform is equipped with a pressure-sensitive edge The ramp cassette is made up of a welded frame of steel profiles and subjected to stress strain analysis. The thesis is accompanied by complete drawing documentation.
Using of Reinforcement Learning for Four Legged Robot Control
Ondroušek, Vít ; Maga,, Dušan (referee) ; Maňas, Pavel (referee) ; Singule, Vladislav (referee) ; Březina, Tomáš (advisor)
The Ph.D. thesis is focused on using the reinforcement learning for four legged robot control. The main aim is to create an adaptive control system of the walking robot, which will be able to plan the walking gait through Q-learning algorithm. This aim is achieved using the design of the complex three layered architecture, which is based on the DEDS paradigm. The small set of elementary reactive behaviors forms the basis of proposed solution. The set of composite control laws is designed using simultaneous activations of these behaviors. Both types of controllers are able to operate on the plain terrain as well as on the rugged one. The model of all possible behaviors, that can be achieved using activations of mentioned controllers, is designed using an appropriate discretization of the continuous state space. This model is used by the Q-learning algorithm for finding the optimal strategies of robot control. The capabilities of the control unit are shown on solving three complex tasks: rotation of the robot, walking of the robot in the straight line and the walking on the inclined plane. These tasks are solved using the spatial dynamic simulations of the four legged robot with three degrees of freedom on each leg. Resulting walking gaits are evaluated using the quantitative standardized indicators. The video files, which show acting of elementary and composite controllers as well as the resulting walking gaits of the robot, are integral part of this thesis.
Equipment for tensioning of mesh on the disc filter segments
Baňoch, Ondřej ; Maňas, Pavel (referee) ; Brandejs, Jan (advisor)
The master thesis deals with mechanical design of device used for stretching and fixing filtration fabric on plastics frames segments for disc filtration device. The thesis was solved in cooperation with IN-EKO Team company that deals with development and manufacturing of filter units. Solution is connected to already ended project FR-T13/699 (end of the year 2013). At the beginning is described the field of filtration devices in broader context with description of the overall functionality these devices and description of used elements in final design. Opening text is followed by concretization of task list and descriptions of concepts variants which are based on FEM analysis of behavior of stretched filtration fabric. The best concept is processed in detail as mechanical design along with pneumatic and PLC control design. Critical part of the design is stretching clamp which was experimentally verified by using experimental clamp in combination with testing machine. The whole design is developed for mass production of disc segments for disc filter which is projected in to the level of the automation.
Design of lattice structures for additive manufacturing using Selective Laser Melting technology
Vrána, Radek ; Maňas, Pavel (referee) ; Koutný, Daniel (advisor)
Metal additive technology allows to create objects with complex shape that are very difficult to produce by conventional technologies. An example of such component is a porous structure which is composed of periodical truss cells. This diploma thesis deals with the prediction of the mechanical properties of very small lattice structures made of additive manufacturing technology Selective Laser Melting. Using the proposed test specimens it was found that real dimensions of the trusses varies with size and orientation to the base platform. It was proposed and tested samples for rod tensile test made of SLM. Based on the real information about dimensions and mechanical properties of rods were predicted mechanical properties of lattice structures. A lot of mechanical tests were carried out to obtain the real mechanical properties. Test results and conclusions are described in the thesis.
Self Adjustable Discharge Valve
Kuruc, Marek ; Maňas, Pavel (referee) ; Technologies,, Jan Jedlička, Emerson Climate (advisor)
This dissertation deals with design of self adjustable discharge valve used in Emerson reciprocating compressors. This work contains research of current state of knowledge, technical analysis of the valve and calculations of basis parameters. Constructional proposal is then presented. Part of the dissertation is manufacturing of prototype and its test. Finally, conclusions for further development are made.
Design of bio-incubator for cell culture transport
Machýček, David ; Maňas, Pavel (referee) ; Paloušek, David (advisor)
In a research part, this diploma thesis deals with dividing incubators into groups according to their kind of use. From the groups biological incubators have been chosen to describe their construction, to explain possibilities of doing sampling and temperature and CO2 control. The research part is concluded by an overview of biological transport incubators for a transfer of cell cultures. In the part of the thesis which deals with a new construction solution some variations are suggested. The most suitable variation has been chosen after a structural technological description, and it is further described in a constructional solution. The frame of the incubator is made from aluminium alloy and is controlled by FEM. There are individual structural nodes being explained and visualised step by step in the construction solution. In the end of the construction solving some information about making the construction and prices of all continuing manufacture are stated.
Stand-up power wheelchair
Juříček, Václav ; Maňas, Pavel (referee) ; Černý, Michal (advisor)
This thesis deals with the structural design and manufacture of special power wheelchair prototype in collaboration with company Brano. Remarkable feature of this wheelchair is the ability to pull its user to an upright position, offering the greater independence, self-sufficiency and medically positive impact on physical functions. The content of this thesis is devoted to a search of the current state of knowledge in the matter, structural analysis of complete wheelchair assembly with a detailed description of each component including the important calculations and analyzes, as well as a description of the wheelchair testing. The conclusion presents summarization of all the results in structural, technological and economic terms.

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