The Ph.D. study focuses on the following fields of mechanics:
· Mechanics of solids. Theory of modelling mechanical systems, constitutive material relations with emphasis on non-linear behaviour, limit state conditions of materials and structures, mechanics of composites, biomechanics, analysis of stress, deformation and dynamic behaviour of selected groups of bodies (including composite bodies), inverse problems of mechanics of rigid bodies, modelling of stress and deformation in selected technological processes (forming), theory of experiments in interactive driving and mechatronic systems, dynamic of vehicles and of machinery, solution of selected problems in vibroacoustics.
· Mechanics of liquides and gases. Flow theory of compressible and incompressible fluids. Flow of gases and vapours. Nonstacionary flow and impact. Orientation on the flow in hydralic machines and heat engines.
· Thermomechanics. Theory of heat and substance transfer. Application of interferometry and other modern experimental methods. Thermodynamic problems of metallurgy and foundry technologies and heat treatment. Applications in the field of design of thermal power-generating machines. Inverse problems of heat transfer.

prof. Ing. Jiří Burša, Ph.D.

1. Critical analysis and modifications of current standards for low cycle fatigue life prediction

   The project goal is improvement of contemporary prediction approaches in the field of low cycle fatigue of metallic components. New approach will be concentrated especially to materials applied in nuclear power plants and will include general triaxial stress states. To reach the goal, appropriate phenomenological models will be selected and corresponding computational algorithms implemented. New experimental program and specimens will be designed in the next step to identify necessary material parameters of the selected models of fatigue damage. Verification will be realized through comparison of results with standard approach according to current technical codes, which is based on the Manson-Coffin’s concept. The solution will cover the area of cyclic plasticity up to 10.000 cycles with special attention given to extremely low number of cycles. Testing must be able to evaluate the areas where the new approach is better, comparable or worse than the classical one. The dissertation will contain objective assessment of all the suggested modifications with accent given to their practical applicability.

   Tutor: Petruška Jindřich, prof. Ing., CSc.

2. Design of the standardization methodologies for the EMA actuators

   The aim of the dissertation thesis is of the design standardization methodologies for developing electromechanical actuator (EMA), deployed in aviation applications, including proposal modularity electrical parts. The proposed procedures will be verified on the development of EMA with a brushless DC motor (EC motor) as an actuator. Part of the thesis will also design HW modular actuator control electronics, at which the proposal is to take into account the condition of maximum modularity of functional units and the use of commercially available components, provided that the same reliability and durability as components commonly used in aviation. The defined requirements according to the standard RTCA DO-160G has to be also respected by HW design. The HW solution will be verified by proposed methods of HALT and AAT tests in order to verify the required lifetime and robustness under the defined extreme operating conditions.

   Tutor: Singule Vladislav, doc. Ing., CSc.

3. Effect of the arterial wall structure on its mechanical properties

   Structure of the arterial wall determines its mechanical properties. Although the main constituents of the arterial wall are known (elastin, collagen, smooth muscle cells) their arrangement remains to be investigated. New knowledge regarding orientation and waviness of collagen fibers will improve the reliability of the arterial mechanical behavior description which is critical for instance when rupture risk of the arterial aneurysms is about to be determined. Knowledge of smooth muscle cells distribution and alignment provides the essential information for simulation of arterial growth and remodeling which in long perspective will help to predict evolution of the atherosclerosis or growth of arterial aneurysm. Structure of healthy arteries will be investigated by combination of biaxial tensile tests of real tissue, mathematic analysis of the microscopic images (using fast Fourier tranformation, phase correlation algorithm etc.) and finite element analysis. Derived information will be used for correction of the constitutive descriptions of the arterial wall in order to better respect the estimated structure. Then, structure of the pathologically changed arteries (with atherosclerosis or wall of the aneurysms) will be investigated in order to understand the effect of mentioned diseases on the arterial structure. In this case it will be also important to link obtained structural information with local geometrical properties of the wall (curvature, wall thickness,...) in order to be able to model the mechanical response of the patient-specific geometries.

   Tutor: Polzer Stanislav, doc. Ing., Ph.D.

4. Effective methods of rolling products heat treatment.

   The aim is to develop the methods of continuous heat treatment of hot rolled materials to reach specified structure and mechanical characteristics. This theme demands a considerable scope of the study of mathematical methods, as well as experimental work applied in thermo mechanics. This interdisciplinary theme is focused on the theory of experiment, measuring methods, scanning and recording of parameters and technological process controlling. The Heat Transfer and Fluid Flow Laboratory supports the problem solution with its laboratory facilities. The participation in the projects, which are oriented to the experimental research of hot processes, is also expected.

   Tutor: Horský Jaroslav, prof. Ing., CSc.

5. Fast Algorithms for Simulation of Long Products Leveling

   Idea of the topic is in the application of Eulerian description of continuum to the simulation of leveling of long products on roller leveling machines. The aim of the work is to enable a fast solution of a nonlinear problem, which is very time demanding if solved by a standard Lagrangian approach. The new algorithm will be helpful for optimization of leveling machine parameters and opens the way to on-line control of the leveling process. Created program should be easily modified for different types of leveling machines and processes like cross-roll leveling on two- or multi-roller machines, leveling of profiles or sheets. The results will be verified by independent simulations with commercial FE programs and by realized experiments. The topic will be solved in cooperation with the company ŽĎAS, producer of leveling machines.

   Tutor: Petruška Jindřich, prof. Ing., CSc.

6. Heat exchangers with hollow fibres forutilisation in biologicaly active environment

   Hollow plastic fibres are used in heat exchangers in past decade. Polypropylene and PVDF capillary are used only recently. Plastic capillary ere flexible and can be easily formed into various shapes. Surface of capillary can be modified and its hydrofobity can be influenced. Heat and mass problems should be studied in this theme. Condensation and evaporation of liquids on inner and outer surfaces of the hollow fibres will be studied.Special cosideration is for bio-fouling applications.

   Tutor: Raudenský Miroslav, prof. Ing., CSc.

7. Identification of dynamic systems with the use of local linear models

   The work will be focused on research of nonlinear dynamical systems identification (mainly in the field of mechatronics) with the application of local linear models (Lazy Learning, LWR, RFWR). Identified dynamic model will be used as feedforward compensator in the composite regulator structure. Theoretical and simulation results will be verified on real systems available at Mechatronics laboratory (edu models, automotive actuators etc.). The modelling in Matlab+ is expected as well as the experimental use of Real-Time Rapid Prototyping dSPACE. For more information: contact supervisor.

   Tutor: Grepl Robert, doc. Ing., Ph.D.

8. Influence of mechanical properties of intraluminal thrombus on the rupture risk of aortic aneurysm

   This actual biomechanical topic aims at computational modelling of stresses in abdominal aortic aneurysms. The objective is to model the interaction of blood (an approximately Newtonean liquid) with the aneurysm wall, covered partially by a porous intraluminal thrombus (remodelled blood clot). For identification of its constitutive models a tailored biaxial testing rig can be exploited and also the permeability of the thrombus should be evaluated experimentally. The computational models will be exploited for stress-strain analyses of abdominal aortic aneurysms.

   Tutor: Burša Jiří, prof. Ing., Ph.D.

9. Modelling, estimation and experimental verification of parameteres of MEMS inertial sensors

   MEMS accelerometers and gyroscopes are widely used in many technical systems from automotive stabilization systems to mobile phones. In the case of application requiring very high precission of the sensor, carefull calibration is needed. The parameters like offset, scale factor, misalignment of 2 and 3 axis sensors are estimated. This work will deal with the development of the new methods for fast and precise calibration. Theoretical approaches will be verified on experimental data.

   Tutor: Grepl Robert, doc. Ing., Ph.D.

10. Numerical modelling of fatigue crack closure

    Fatigue crack closure mechanism is well described in the literature and confirmed by experimental observation. Detail prediction of the crack closure in the case of three-dimensional structure with complex crack shape is still open scientific topic. Therefore, general goal of the work lies in the accurate numerical modelling of plasticity induced crack closure in the case of 3D crack front. The numerically obtained results will be experimentally evaluated in our own laboratory. Important issue is also separation of single effects responsible for fatigue crack closure phenomenon.

    Tutor: Hutař Pavel, prof. Ing., Ph.D.

11. Robust Fault Detection and Isolation for Nonlinear Systems

    Application of poweful microcontrollers allows implementation of advanced supplementary functions. One of an important areas of recent development are algorithms for detection, isolation and management of faults in mechatronic systems. This work will deal with the development of new algorithms based on local linear models and soft computing methods. Theoretical and simulation results will be verified on real systems available at Mechatronics laboratory (edu models, automotive actuators etc.). The modelling in Matlab+ is expected as well as the experimental use of Real-Time Rapid Prototyping dSPACE.

    Tutor: Grepl Robert, doc. Ing., Ph.D.

12. Sandwich polymer materials failure in quasi-brittle area

    Due to increase of the long term application of the polymer materials failure in quasi-brittle area became important scientific topic. Therefore, the general goal of the work lies in the accurate description of the slow crack propagation in the case of sandwich polymeric structures taking into account residual stresses. Slow crack growth can be described by the corresponding fracture mechanics parameters and using advanced numerical modelling lifetime of the polymer structure can be predicted. The correlation between experimental data of PCCL and numerical model will be presented.

    Tutor: Hutař Pavel, prof. Ing., Ph.D.

13. State estimation of wheeled vehicle with application on traction stability control

    The work will be focused on research and development of state and parameter estimation of dynamic holonomic model in real-time. Application area includes e.g. traction stability systems. The simulation modelling in Matlab+ environment is supposed to use as well as experimental work with Real-Time Rapid Prototyping hardware dSPACE, which is currently de facto standard in automotive industry. Designed simulation models will be based on both holonomic as well as nonholonomic kinematics. Theoretical results will be practically verified on particular real model of four wheeled vehicle.

    Tutor: Grepl Robert, doc. Ing., Ph.D.

14. Theory development and experimental verification of hydraulic descaling

    During the steel production and hot processing the surface of steel is exposed to an oxidizing atmosphere and surface oxide layer (called scales) is formed. These scales are removed using high-pressure flat jet nozzles. During this process surface quality (amount of remaining scales) is monitored and the amount of heat dissipated from the steel is measured. The quality of the surface depends not only on the configuration of the hydraulic spray, but also on the quality of steel (chemical composition), thermal treatment and coating. Water spray causes a sharp drop in temperature and thus significant change of material properties of scales. Moreover, they are usually not formed by homogeneous layer. It is a layer composed of several types of scales: wüstit, magnetite and hematite; whereby their ratio depends on the oxidation temperature. Oxide scales are usually porous, which allows water to penetrate into the cracks which may lead to steam explosion due to very high temperatures (above 1000°C) of scales. Hydraulic descaling is very complicated process, which consists of the mechanical effect of the water jet, thermal contraction of the surface layers, shear stresses at the interface of scales / steel, bending of scales due to temperature gradient and steam explosions in the cracks. The aim is to create theory and verification model of hydraulic descaling and describe the principles in this combined thermo-mechanical stresses. Computational model based on the theory will be used for verification of developed theory. Results from the model will be compared with results obtained from real descaling measurements in laboratory. Model should serve also for optimization of the hydraulic descaling for hard to descale materials (e.g. steel with increased content of silicon for the automotive industry).

    Tutor: Pohanka Michal, doc. Ing., Ph.D.