Arterial stenosis is a disease characterized by the buildup of a waxy substance inside the artery, which is associated with certain risks. It is difficult to eval- uate the severity of the stenosis, yet the diagnosis can become more accurate using computational fluid dynamics simulations. The present thesis introduces and applies the model of hemodynamics based on the Navier-Stokes equations, implemented in the FEniCS software employing the finite element method. The main focus lies on the prescription of the boundary condition at the outlet of the computational domain. The impact of the outlet boundary condition on medically significant quantities such as the wall shear stress is analyzed in a two- dimensional benchmark case. It appears that the right choice of the boundary condition is fundamental, in particular when vortices occur and propagate across the outlet boundary. The next part of the work is dedicated to the prescrip- tion of the outflow rate in the case of more than one outlet, corresponding to an artery branching inside the computational domain. The physically meaningful flux distribution is derived introducing Murray's law and its extension. Finally, the blood flow is simulated in a three-dimensional geometry of a patient-specific carotid artery. 1

This thesis is focused on study of blood flow through the descending aorta using mag- netic resonance imaging and computational hemodynamics. This combination enables simulations of blood flow in patient specific geometries and under various circumstances such as higher heart rate, velocity or blood pressure. The theoretical part describes the governing equations of the blood flow and possible choices of boundary conditions. The weak formulation and discretization in space and time, which leads to the finite element approximation, is presented. The magnetic resonance data is presented in the second part. The process of segmenta- tion is described together with the preparation of the velocity data for comparison with simulation results. Limitations of magnetic resonance imaging are also presented. The developed methodology is one of the contributions of this thesis. The qualitative and quantitative comparison of simulation results and the magnetic res- onance velocity data is presented in the third part. The main result of the thesis is in the comparison of the flow under different wall boundary conditions. The most important finding is that the best fit for the data is the free-slip wall boundary condition, which is the opposite of commonly used no-slip wall boundary condition. 1

Traditional all wooden construction joints are currently widely used when historically valuable buildings are being reconstructed. These construction joints are indispensable and irreplaceable in order to maintain cultural heritage for our future generations. They underline the importance of the wooden structures and buildings, which in many cases might have incalculable historical, artistic as well as financial value. However, increased interest brings many challenges and potential risks that need to be taken into account and eliminated by appropriate solution(s). Adequate employment of these wooden joints requires a research-based approaches, which allows proper implementation within existing constructions while maintaining its reliability and safety. Main aim of preset doctoral thesis was to contribute to the development of suitable methods for analyzing mechanical behavior of all wooden construction joints, especially dowel joints, which are mainly used for reconstruction of damaged wooden elements or their parts. For such purposes, various methods (models), based on combination of theoretical, experimental and numerical approaches, has been used. This work was divided to a) basic mechanical tests of solid wood and b) complex finite element analyses of all wooden joints and constructions. Mechanical behavior in tension, compression, bending and shear was tested on small clear specimens made of spruce (Picea abies L. Karst.), beech (Fagus sylvatica L.) and oak (Quercus robur L.). Analyzed species were chosen as a most important historical as well as present European building materials. Mechanical response was captured using cameras in stereovision 3D configuration in order to obtain full-field displacement and strain data sets. Based on obtained data, material characteristics were determined and verified in frame of assembled material models for finite element analyses (FEA). Verified elasto-plastic material models were used as main material inputs for complex FEA for evaluation of mechanical response of joints and constructions subjected to load. Furthermore, material characteristics were used in calculations of mechanical properties of dowel joints. Numerical analyses were done using ANSYS software with parametric design language (APDL). Experimental results of single-shear dowel joints are in agreement with theoretical approach according to European Yield Method (EYM) theory, which was used for determination of joints and fasteners yield strength. FEA proved that assembled elasto-plastic material models can predict the ultimate strength even in complex tasks, and therefore, can be used for more reliable designing of wooden constructions and joints in variety of configurations.

This work deals with strain analysis of tree during felling. The main goal is to describe the origin of the deformation field. Another aim is to explain the effect of individual cuts on the size of deformation forces. Two relatively new methods in the field of wood are used to investigate the experimentally, namely digital image correlation (DIC) and finite element method. The work deals with methodical foundations for tree research during its felling. The DIC method measured seven trees in the forest when felling. Using the results obtained by this experiment, the numerical model was validated. This comparison suggested higher rigidity of the body using the finite element method compared to the actual tree, but the reaction was similar. With respect to the higher stiffness, the model was used to describe the deformation field inside the tree and to describe the effect of each cut on this field. The thesis also draws attention to the methodological errors that can occur during felling and which have been described in the experiment. Another output is an indication of the direction in which further measurements should be made and the errors that occurred during this measurement to avoid repetition.

Recent years have seen a rising interest in the use of computational fluid dynamics for investigating the hemodynamics in brain aneurysms. Hemodynamic parameters, such as wall shear stress or oscillatory shear index, are among the indicators used to detect higher risk of aneurysm rupture. This thesis describes the blood flow by generalized Navier-Stokes equations with the Navier slip boundary condition imposed on the impermeable rigid vessel wall, which is implemented by way of Nitsche's method. The influence of constitutive models and the Navier slip wall boundary conditions on the resulting blood flow and hemodynamic parameters is investigated. Five different non-Newtonian constitutive models are first compared on a 2D rectangular domain. The Carreau-Yasuda, modified Casson, and Quemada models are then employed to investigate the differences in one patient-specific aneurysm geometry obtained by CT scan. All non-Newtonian models are compared with the Newtonian model. Both steady and pulsatile simulations are performed to obtain the velocity field and hemodynamic quantities, such as wall shear stress, time-averaged wall shear stress, oscillatory shear index, and oscillatory velocity index. The results for this particular case showed that non-Newtonian models do not have a significant impact on the computed...

This master’s thesis deals with the strength analysisby frame lift cage with lift capacity of 675 kg used the Finite Element Method (FEM). Furtheris performed the calculation of the guideanchoring instituted for this steel structure and the strength analysis of the used guides according to norm ČSN EN 81-1. The thesis also includes the drawing of the frame lift cage.

The topic of this master`s thesis is the strain - stress analysis of the manipulator construction. This manipulator is used in the company Legios for positioning steel weldments at hand welding. A separate chapter is devoted to check calculations of main joints using the analytic method.

This thesis deals with the optimalization of MAGMA Alficar vehicle driveshaft, which in extreme operating conditions leads to destruction. The finite element method is used to analyze the shaft, which is a modern solution of the stress-strain analysis in designing practice. The classical method of the stress analysis calculation and the suggestion of the solution to the problem of destruction are also included.

This thesis is aimed on three-dimensional finite element time domain analysis. Vector finite elements are used for analysis of cavity resonator made from PEC and filled with vacuum. Results are compared with classical “nodal” finite elements and with published literature.

Subject of my masters's thesis is bearing construction from wood of pedestrian bridge via river Bečva in Karolinka. Span of the pedestrian bridge is 37 meters. Three 3D models of global model of whole construction and support models are created. The resulting draft is worked up in details. This work aim on models of joints of wooden parts, boundary conditions and global function of static model.