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. Anorganic polymer filtration units for heat exchangers in high temperatures area

   High temperature heat exchange is a specialized field where the considerably more expensive equipment than at lower temperatures are used. It is therefore understandable effort to maintain this equipment in optimum process conditions. The heat transfer fluid media at high temperatures often contain solid particles and chemically aggressive components. The removal of solid particles and the gaseous pollutants at such the conditions is the really expensive process. Non-brittle anorganic polymers which are thermally and chemically suitable material for the formulation of porous filtration layers should be the correct way to develop parts of heat exchangers for the high temperature heat exchange optimal applications.

   Supervisor: Svěrák Tomáš, prof. Ing., CSc.

2. Application of mechatronic solutions for precise manipulation and measurement for cell cultivation

   The work will be focused on research and development of technical solution specially suited for advanced conditions of the cell cultivation in thermal incubator. The key issue is the precision position control in several axis with simultanous data processing (temperature, C02 concentration). There are high requirements given on technical solution, e.g. disinfection of the whole system, low dustiness, fault-tolerant design of ECU. The use of automatically generated C code is assumed based on tools Matlab/Simulink (RT Workshop, RTW Embedded Coder). The testing of implemented algorithms will be carried out also using HIL simulation. The dSPACE hardware will be used including FPGA emulation of time critical parts of application (e.g. simulation of sensors). The work will be closely coordinate with partner from Faculty of Medicine, MUNI.

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

3. Description of the slow crack growth in polymer materials

   Due to increase of the long term application of the polymer materials process of slow stable crack growth 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 polymeric structure under complex loading conditions taking into account residual stresses. Slow crack growth can be described by the corresponding fracture mechanics parameters and plays an important part in estimation of this life time. The correlation between experimental data of PCCL and numerical model will be presented.

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

4. Design and implementation of control algorithms on FPGA

   The work will be focused on research and development in the field of FPGA in mechatronics applications. The aim is to implement selected signal processing and control algorithms on FPGA and further to evaluate this approach. Key advantage of FPGA is the speed and parallelism of the code processing. The example of application is the advanced sensorless control of BLDC motor used as fuel pump in aircraft engine. The use of automatically generated HDL code is assumed based on tools Matlab/Simulink with the dSPACE hardware. The work will be closely coordinate with industrial partner (UNIS) and with the current project of 7FP ESPOSA.

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

5. Development and optimization of control SW for actuators used in critical applications

   The subject of the research and development will be a highly reliable control SW for electronically commutated (EC) motors with respect to usage in critical applications in aviation. According to the latest technological trends in this industry (all-electric aircraft) hydraulic wirings are replaced with smart actuators based on electrical servomotors. This results in higher reliability and usability. The main aim of the dissertation thesis will be the design of complex control SW for fuel pump with direct current EC motor as actuator. The SW has to be developed in compliance with the standard DO-178B category B. Due to the safety of this system Fault Tree Analysis has to be performed and based on its results appropriate redundant control algorithms increasing safety and reliability have to be designed. Health monitoring, failure prediction and detection (Built-In-Test) algorithms will be part of the control SW. Actuator control will follow the latest trends and algorithms including both sensor-based and sensor-less control of EC motors. All components of the control system will be tested and verified using fuel stand simulating real fuel system of an aircraft engine.

   Supervisor: Krejsa Jiří, doc. Ing., Ph.D.

6. Energy harvesting power supply for MEMS applications

   The PhD thesis deals with a development of an autonomous power supply for MEMS applications. This energy source harvests energy from surroundings of a powered application and it will be based on energy harvesting technologies. Energy harvesting methods present a basic principle of generating energy from ambient sources. These sources of ambient energy can be in form of solar radiation, mechanical energy of movement, vibration and shocks, energy of thermal gradient, etc. Generally the amount of harvested energy from these ambient sources is in very low level. However, with the development of modern electronics these sources of energy are sufficient for some applications, especially MEMS. The energy harvesting device presents a mechatronic system and it consists of several subsystems and behaviour of these subsystems is mutually affected. The respect of individual feedbacks is very important for the development of the energy harvesting device. A Simulation modelling of individual feedbacks of this mechatronic device will be the main objective of this PhD thesis. The simulation models will be verified on the base of experiment and used for optimization studies with respect to powered applications. The aim of this thesis will be the development of an energy harvester for MEMS applications with respect to minimal dimensions and maximal output power. The main objective of this work deals with application of this device in industrial practice.

   Supervisor: Hadaš Zdeněk, prof. Ing., Ph.D.

7. Experimental and computational modelling of failure of elastomers, especially in vicinity of their interface with a crystalline material

   Failures of hyperelastic materials represent an important problem of reliability of tyres. The objective is to increase the level of computational assessment of failures in a composite „rubber-steel fibre“. Fractures occur in this composite mostly in the elastomer matrix in the vicinity of the bimaterial interface but a generally valid failure criterion was formulated neither for elastomers till now. Elastomers fail by different mechanisms in dependence on the stress state, which is very specific in the vicinity of the material interface. A comprehensive experimental and computational modelling is necessary to verify (or falsify) the failure hypothesis proposed lately in our institute.

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

8. Generalized linear elastic fracture mechanics and its applications

   Engineering structures contain many singular stress concentrators. The most typical is sharp v-notch. Important set of singular stress concentrators represents material joints or material interfaces (surface layers, composite materials). Many further examples can be found in practice. Common characteristic of mentioned stress concentrators is their stress singularity different from 0.5 (in contrast with a crack). It means that classical approaches of linear elastic fracture mechanics cannot be used. The aim of PhD thesis is to use procedures of generalized linear elastic fracture mechanics for estimation of the moment of initial and a manner of crack propagation from general singular stress concentrator. From point of view of engineering applications the procedures derived will be used e.g. for determination of a manner of layered materials failure (material field), for determination of initial crack propagation from sharp v-notch (in structure design field) or for determination of free surface influence on fatigue crack propagation. Commercial FEM code Ansys and mathematical software Matlab will be used for necessary numerical calculations.

   Supervisor: Náhlík Luboš, prof. Ing., Ph.D.

9. Improvement of rupture risk preditiction at abdominal aortic aneurysms using computational modelling

   This actual biomechanical topic aims at experimental and computational modelling of the stress-strain states in abdominal aortic aneurysms (AAA) and at improvement of prediction of their rupture. Hitherto patient-specific computational models have been realized using material parameters determined by measuring of real AAA tissues and they have shown that some other factors may influence the rupture risk, such as AAA tissue remodelation, its stress-free state, intraluminal thrombus, stress concentration in the vicinity of arterial branches, collagen fibre orientation, etc. The objective of the topic is a maximum exploitation of experiments in a credible computational models used for AAA rupture prediction, and improvement of the quality of prediction by taking some of these factors into account.

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

10. Modelling of Stress-strain Field at the Tip of Shear-mode Cracks by Finite Element Method.

    The aim of the work is a development of 3D models of stress-strain distribution at the tip of cracks loaded in modes II, III and II+III using finite element method in an elasto-plastic aproximation. Geometry of cracks will be considered as both ideally plannar and tortuous.

    Supervisor: Horníková Jana, doc. Ing., Ph.D.

11. Plastic heat exchangers

    Energy cost require to search for new sources. Heat exchangers used in low potential applications require special design and use non-corrosive materials. Plastic materials are used with advantage. Plastic hollow fibers are used as basic part for heat exchangers in laboratories, heat pumps and similar fields. Fibers made of polypropylene of PVDF are still used rarely. These fibers are flexible and can be used in suitable shapes with advantage. Cleaning of flexible heat transfer surfaces is easier than the solid surfaces. The goal of the study is to find the way and limits how to use hollow plastic fibers for heat exchangers.

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

12. Short fatigue crack propagation description

    Usually fatigue crack propagation is described by simple Paris-Erdogan law, where fatigue crack growth rate corresponds to stress intensity factor value. In the case of short cracks, plasticity, microstructure or free surface effects play role. The aim of the work is using numerical simulations in ANSYS software and our own experimental results find possibility of short fatigue crack fracture mechanics description. Important issue is also separation and quantification of single effects responsible for anomalous short crack behaviour.

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

13. Solution of general stress concentrators in laminates with foam layers

    Ceramic foam like structures are of technological interest because of their potential use in a number of industrial branches. Manufactured cellular materials have been developed for a range of applications like high temperature filters, tissue engineering as bone replacement material, insulation materials and light-weight reinforcement. Since a direct numerical approximation of engineering structures composed of cellular or heterogeneous materials is computationally prohibitive, homogenization procedures are of great importance. Especially in the presence of high stress-strain gradients there is necessary to involve in computations an influence of characteristic length of cells of original foam material. It can be done using a suitable gradient elasticity model. The goal of the thesis is a description of general concentrators like notches or crack on interfaces in composites with foam layers.

    Supervisor: Kotoul Michal, prof. RNDr., DrSc.

14. The structure strength optimization at the connection place of the composite and metallic part of the drive shaft of hybrid construction.

    At some elements (for example drive shafts) of contemporary driving systems the substitution of classic metallic materials (esp. steels) by fibre composites occurs . Composite materials with polymer matrix do not withstand the high contact pressures and intensive friction. Solution of this problem is a hybrid composite-metallic construction with the important role of both parts connection. The aim of the doctoral dissertation work is a computational stress, strain and strength comparative analysis making use of FEM of some connections (classic cylindrical sticking connection, conical connection, flange bound connection, resp. others),selection of the best one and following structural strength opimization at connection place. An experimental verification is assumed.

    Supervisor: Vrbka Jan, prof. RNDr. Ing., DrSc., dr. h. c.