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Application of DIC method for measurement of deformations on small specimens
Vejchoda, Ondřej ; Houfek, Lubomír (referee) ; Návrat, Tomáš (advisor)
This diploma thesis tries to find the most suitable optical system for measuring deformation displacements on the surfaces of bodies. The first chapter describes the systems and methods that will be used. The second chapter is devoted to the design of the experiment. It describes the preparation of the experiment from the point of view of software and hardware and what are the important preliminary preparations. The last chapter contains the results of experiments and evaluation of the systems.
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Analysis of uncertainties in the calculation of residual stresses
Dubravec, Kristián ; Houfek, Lubomír (referee) ; Návrat, Tomáš (advisor)
This thesis is about analysis of uncertainties in the calculation of residual stresses, which are homogeneous and measured by the hole-drilling method. Stochastic approach is explained using models of beams. Theory of residual stresses is included. Source code for evaluating residual stresses deterministically and stochastically is created using the Python language. Sensitivity analysis of input parameters is performed.
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Experimental measuring of Siemens mechatronic device.
Koláček, Martin ; Houfek, Lubomír (referee) ; Koláčný, Josef (advisor)
The aim of this work is experimental measurement followed by acquisition and reconstruction of data from the image format. Experimental work is focused on verifying properties of a real electric drive with synchronous motor and frequency converter. Special attention is paid to the influence of system parameters on the time flow of monitored values. There is also solved backward reconstruction of the data during exporting of outputs from the measured system.
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Simulation of vehicle dynamics using V-REP software
Borek, Dušan ; Houfek, Lubomír (referee) ; Grepl, Robert (advisor)
This theasis deals with modeling dynamics and visualization of experimental vehicle CAR4 in software V-REP. The first part shows introduction with V-REP and its possibilities for usage in simulations. The second part presents modelling of CAR4 vehicle and its control by using software V-REP and Matlab. In last part are models of vehicle tested in simulation
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Models of Dynamics and Responses of Multi-body Systems
Kšica, Filip ; Houfek, Lubomír (referee) ; Hadaš, Zdeněk (advisor)
The aim of this diploma thesis is to evaluate the potential of available methods for simplification and reduction of complex models of technical systems and their integration with experimental models. Finding methods, which would allow us to create models and run simulations in shorter periods of time, is key in design process of modern technical systems. In the beginning of this thesis, a theory necessary for understanding and application of presented methods is given. These methods can be separated into two groups, first as experiment related, second as simulation related. The first group contains methods for experimental evaluation of response and its use for dynamic system identification. The second group contains methods of finite element model creation, with the usage of standard structural elements as well as Component Mode Synthesis substructures, and these models are in the following step reduced into state space models. In the next step, all presented methods are applied on simple experimental structure. In conclusion, the results of simulations are the subject for comparison not only from quantitative point of view, but also, for the purpose of practical application, in terms of time, feasibility, versatility and accuracy. The system identification method along with state space method proved to be very suitable. The results presented in this thesis might help, by selecting the appropriate method, in simpler evaluation of dynamic properties of technical structures.
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Simulation modeling of parallel mechanisms
Cintula, Ladislav ; Houfek, Lubomír (referee) ; Březina, Lukáš (advisor)
Parallel mechanisms are characterized by their kinematic structure presented a closed kinematic chain. The end effector of mechanism is then bound to a base of over one arm. This design provides an advantage especially at high stiffness of mechanism and related properties. The disadvantage of such a structure is then usually very limited working space. In terms of simulation modeling is the construction due to its complexity rather problematic. The aim of work is design comprehensive simulation model chosen parallel mechanism and its analysis in selected working modes. Expected to use Adams simulation environment, if necessary. Matlab - SimMechanics and Ansys.
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Computational modelling of noise inside cabin of aircraft VUT 100 Cobra
Prnka, Jiří ; Houfek, Lubomír (referee) ; Švancara, Pavel (advisor)
This master’s thesis deals with the computational simulation of low-frequency noise inside the cabin of small commercial airplane VUT 100 Cobra. For this low-frequncy range deterministic methods: Final Element Method (FEM) and Boundary Element Method (BEM) are used for simulation of the dynamic behaviour of the object. FEM has been used to compute eigenmodes and eigenfrequences of the structure of the aeroplane cabin and of the acoustic space inside cabin. Then response to harmonic excitation of engine represented by unit forces in place of contact has been computed. Obtained velocities on the surface of the cabin are then used as the basis for the noise calculation inside the cabin using BEM. After that effect of some construction modifications on sound level inside cabin are evaluated by computational modelling.
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Stress analysis of rotor packet of synchronic generator
Bureš, Jiří ; Houfek, Lubomír (referee) ; Petruška, Jindřich (advisor)
This diploma thesis deals with distribution stress and strain of sheets metal of rotor packet and in critical locations of supporting bars of synchronous generator. These variants are calculated and one another comparison of analytic calculation results, numeric calculation of 2D model and numeric calculation of 3D model in three vriants ( with bars of rectangle section, circular section, with upper radius). The calculation include influence of thermal expansion, centrifugal force, interference of the packet on the shaft and prestress in the axial direction of bolt. To creation of geometric model and numerical calculation is used program ANSYS 11.
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Application of ductile fracture models in computational simulation of manufacturing operations
Hůlka, Jiří ; Houfek, Lubomír (referee) ; Petruška, Jindřich (advisor)
This diploma thesis is an introduction to the ductile fracture under large plastic deformations and is focused to numerical simulation of this type of problems. Explicit finite element method (FEM) is discussed in theoretical introduction as the most powerful tool for numerical calculations in this area. Actual state of research and possibilities of ductile fracture simulations are presented. Applicable fracture criteria are collected in a summary sheet and the most important ones are selected and commented in detail. The problem of implementation of selected criteria into commercial FEM packages is discussed, too. Main part of the work is presented in chapters 7÷9 where two ductile fracture criteria (Equivalent Fracture Strain and Johnson-Cook) are applied to numerical simulation of material cutting. All results were obtained with ABAQUS/Explicit 6.5.1 and their verification was realized by experimental measurement.
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