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Original title in Czech: Inženýrská mechanikaFSIAbbreviation: D-IMEAcad. year: 2016/2017
Programme: Applied Sciences in Engineering
Length of Study: 4 years
Accredited from: 1.1.1999Accredited until: 31.12.2020
Profile
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.
Guarantor
prof. Ing. Jiří Burša, Ph.D.
Issued topics of Doctoral Study Program
The thesis will deal with research in the field of control and identification of nonlinear dynamic systems using methods based on the idea of local linear models (Lazy Learning, LWR, RFWR). The identificated inverse dynamic model will be used as a feedforward compensator in the structure of a composite regulator. The results of the research will be verified experimentally with real systems available in the Mechatronics laboratory (education models, automotive actuators, etc.) using the Matlab/Simulink computational environment and available hardware resources. Implementation in the form of an electronic control unit with a microcontroller is expected.
Tutor: Grepl Robert, doc. Ing., Ph.D.
Innovative modern designs require, with respect to the desired functions, usage of modern materials. Important are the mechanical and thermal properties. Hand in hand with the development of advanced materials goes the development of experimental techniques, for cost effective testing of these materials, eg. non-contact optical methods. The aim is to select suitable experimental methods for effective testing of structure parameters. Chosen methods have to give reliable and repeatable results for a certain class of engineering problems. The suitability of selected experimental techniques will be validated through a series of experiments. The experimental results will be compared with analytical and numerical solutions of elementary problems. Also the comparison with traditional experimental methods should be done. It is primarily intended to explore the use of experimental methods of structures for the aerospace, cosmic and automotive industries. If this work proves that the results of the advanced experimental techniques are sufficiently reliable and in good agreement with the elemental analysis of problems and the results of experiments using traditional methods, it will be possible to use these innovative experimental techniques in industrial applications.
Tutor: Návrat Tomáš, doc. Ing., Ph.D.
Cranioplasty is carried out after osteoclastic trepanation of the skull (creniectomy) or in trauma cases with a partial loss of cranial bone. Decompressive craniectomy is a kind of neurosurgical operation that is carried out for a radical reduction of intracranial pressure. This surgery is necessary to proceed in cases of severe brain trauma or cancer. Cranioplasty is necessary for mechanical protection of the brain, to avoid intracranial pressure fluctuations and because of patients' mental condition after the craniectomy. Bone grafts taken from ribs or cranial vault are common materials used in cranioplasty. However, currently it is also possible to use implants made of biocompatible resin or metallic alloys. Implants are designed and manufactured using the latest computational and technological methods, including rapid prototyping. These methods allow the production of implants for specific patients (so called the "patient-specific" approach). A part of the implant designing process is the biomechanical analysis. Considering the implant geometry, material, loading and final implementation, a series of partial biomechanical problems is usually necessary to solve. The aim of the dissertation thesis will be the solution of biomechanical problems related to mechanical interaction of the skull with implants, with a special focus on the implant geometry, materials and connection.
Tutor: Florian Zdeněk, doc. Ing., CSc.
Principle of nanoindetation is pushing a tiny tip into the material at the level nm - the output of the experiment is the dependence of the force-displacement tip. In the first phase, the objective is to determine the material characteristics so as to ensure consistency between experimental and computational (finite element method) determine the dependence of the force-displacement tip. For a running calculation model will be in the next phase of computational modeling process nanoindetation for bodies with different material properties.
Tutor: Fuis Vladimír, doc. Ing., Ph.D.
The reduction of coronary blood flow reduces the supply of oxygen and nutrients to cardiac cells, which results in inhibition of cell metabolisms. This is accompanied by a decrease of intracellular ATP concentration and pH. These changes affect substantially the activity of ion transporters in cell membrane. The aim of this work is to mathematically formulate the effects of metabolic inhibition on membrane ion transport system and to explore the final impact of these effects on electromechanical activity of cardiomyocytes by means of computational modelling.
Tutor: Burša Jiří, prof. Ing., Ph.D.
The aim of this work is mathematically formulate the changes in membrane ion transport and in excitation - contraction coupling in failing hearts and to explore the consequences of these changes for electromechanical activity of cardiomyocytes by means of computational modelling.
This topic is very actual in basic research and includes potential impacts on clinics. Membrane currents in muscle cells of myocardium evoke their contraction which is not perfectly synchronnous but propagates throughout the myocardium. Defects of these currents disturb the synchronization of individual layers of myocardium wall and consequently weaken the myocardial contraction. This work aims at exploitation of finite element method for modelling and explanation of relations between the asynchronous contraction of the individual layers of myocardium and the total effectivity of the heart contraction.
Vocal folds posturing to phonation position is a fundamental aspect of human voice production control. A detailed study of this mechanism is important for understanding of voice production in healthy individuals and particularly patients with voice disorders. Aim of the work is to create three-dimensional finite element model of laryngeal cartilages and soft tissue of the vocal folds for analysis of the motion and stress of vocal folds during setting to phonation position. Movement of the laryngeal cartilages will be activated by the action of the muscles of the larynx. Created computational models will be used for stress-strain analyses of pathological changes of the vocal folds such as unilateral vocal fold paresis.
Tutor: Švancara Pavel, Ing., Ph.D.
Human voice production is based on interaction between by air flow excited oscillations of the vocal folds and acoustic processes in the vocal tract. A detailed study of this mechanism is important for understanding of voice production in healthy individuals and particularly patients with voice disorders. The aim is to create finite element model of interaction between self-excited oscillation of the vocal folds and acoustic spaces of the vocal tract. After verification of the model results by comparison with experimental data, on this model further analyze the influence of some pathological changes in the tissue of the vocal folds (Rinke's edema, Sulcus vocalis etc.) on the vocal folds oscillations and produced voice.
The topic is prepared and solved in a close cooperation with Skoda Auto, which participates in funding the study and offers a work position after it is successfully finished. The theme represents a broad area of problems that can be solved by a parallel work of more students. Partial problems to be solved include questions of optimal design of geometry of products, tools, material and process parameters and their influence to spring-back, stability of dimensions, workability and damage of both products and tools. Each student will work on a specific problem, which have a common goal to improve computational modeling and integrate it fully to virtual design of new products and processes.
Tutor: Petruška Jindřich, prof. Ing., CSc.
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 lifetime. Numerical model will be validated by correlation with experimental data of PCCL Leoben and Polymer Institute Brno.
Tutor: Hutař Pavel, prof. Ing., Ph.D.
There are different approaches for the prediction of bearing life. Most known approaches provide conservative estimates of life, which often do not match with the experimental results. The question is how to improve the estimate of life using advanced numerical methods. The goal of the work will be proposal of methodology for life of rolling bearings using numerical simulations based on the finite element method, and a modification of an appropriate criterion for assessing the fatigue strength under multiaxial stress state. An integral part of the work will be experimental validation of the proposed methodology.
The topic is motivated by the need of computational modelling of mechanical behaviour of composites used in production of tyres. At fibre composites with rubber matrix and steel reinforcing fibres (wires), the standard anisotropic hyperelastic constitutive models are not sufficient because they neglect the bending stiffness of fibres. Within the framework of previous doctoral theses a method was proposed how to include the bending stiffness of fibres into the constitutive model on the basis of Cosserat theory of elasticity. The created FEM solver is capable to solve some simple models of these composites but has significant limitations in the model size and problems with convergence. The topic aims at mathematical analysis of the conditions of solvability of the respective systems of equations and at creation of an own implementation of this theory with application of convenient methods. This should enlarge the range of problems for which the theory can be applied.
Interdisciplinary research, focus on experimental work, methods of measurement, data recording and evaluation. The aim is to design, develop and optimize sensors and to subsequently develop of numerical methods for processing data obtained from sensors.
Tutor: Kotrbáček Petr, doc. Ing., Ph.D.
Structure of arterial wall defines its mechanical properties. Although all the relevant constituents of arterial wall are well known (elastin, collagen, smooth muscle cells) their organisation in arterial wall is still a subject of research. Gaining of knowledge regarding orientationn and waviness of collagen fibers will help to describe mechanical behaviour of the arterial wall more accurately. This is vital for instance in abdominal aortic aneurysms rupture risk assessment. Knowledge of distribution and organisation of smooth muscle cells will help us to model growth and remodelling processes more reliably. This will help us predict atheroclerosis or development of existing arterial aneurysm.
Tutor: Polzer Stanislav, doc. Ing., Ph.D.
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.
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.
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.
The topic is motivated by properties of elastomers and composites used in production of tyres. Rubber and other elastomers show large elastic strains the computational modelling of which exploits hyperelastic constitutive models. However, under extremely large strains (up to hundreds percents) also non-elastic effects occur (Mullins’effect, plasticity, viscoelasticity) and cause significant differences between models and reality as well as secondary anisotropy of the elastomer properties. Recently constitutive models are broadly developed for description of these effects. The topic aims at anisotropic behaviour of elastomers caused by Mullins’effect, implementation and exploitation of the respective constitutive models with their eventual application at fibre composites with elastomer matrix (rubber reinforced with textile and other fibres).
Navigation in outdoor environment with no or rough roads is currently in focus in autonomous mobile robot navigation. The goal of the thesis is to create a set of navigation algorithms for mobile robot that enables the motion in the outdoor environment of the size of a football field. Localization subsystem should be based on the fusion of data from sensors of various principles with respect to the robustness of localization and cost efficiency. The ability to detect and use natural landmarks is of special interest.
Tutor: Krejsa Jiří, doc. Ing., Ph.D.
Energy harvesting from ambient mechanical vibrations is main aim of several international research programmes in recent years. The usage of ultra-low power electronics forces the development of energy harvesting devices, which will replace batteries in wireless communication modules. The linear vibration energy harvesting devices operate in resonance and the correct operation depends on a frequency stability of excited vibrations. Non-linear devices have potential to operate in the wide bandwidth of excited vibration frequencies or these devices will use nonstable responses to unstable operation. Main aim of this research is development of nonlinear energy harvesting devices for autonomous powering of wireless modules and the mechatronic approach will be used for this development process.
Tutor: Hadaš Zdeněk, doc. Ing., Ph.D.
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.
Residual stresses are stresses acting permanently in components without an external load, mostly as a result of previous technological processes. When an external loading occur the residual stresses could have a harmful or beneficial effect. One of the most commonly used methods for measuring residual stress is a method of drilling a hole. The aim of the work is to create a computational model for simulating the hole drilling method, including the uncertainties that can arise in a real situation.
The work will be focused on research and development of state and parameter estimation of dynamic 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. Theoretical results will be practically verified on particular real model of four wheeled vehicle.
In a world of continuous innovation and global competition, the manufacturers and R&D centers must be able to predict a dynamic behavior of the product without producing of a physical prototype. The development of mechatronic products, which contains several multidisciplinary subsystems, requires a virtual prototype for parameters estimation and prediction of product behavior. Traditional methods for the multidisciplinary modeling of mechatronic products, like FEM, are demanding and time-consuming in a development or innovative phase of product cycle. This leads to the necessity for a using of effective computing methods which are suitable for the integration of multidisciplinary models. Main aim of this research is application and evaluation of used approaches for integrated multidisciplinary models of mechatronic products. This model has to effectively provide prediction of dynamic behavior and properties of developed or innovative mechatronic product.
Failure probabilty of ceramic heads of the total hip joint endoprosthesis is calculated by Weibull weakest link theory. General 3-axis stress rices in the ceramic head under ISO 7206-5 loading and this stress has significant tensile component in the circumferential direction (first principal stress). Previous research included in this calculation model only the tensile stress and the remaining components were not considered. The aim is to extend the computational modeling of head's failure probability of the other two principal stresses.
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.
The strategy of automobile manufacturers is increase of the light source output while outer dimensions stays same or reduce. This leads to higher demands on the thermal management from the light source to outside of the lamp body. Temperature distribution and other physical important quantities in the operating conditions will be experimentally found in specific cases. The numerical simulation will follow to provide the optimal improve of the lifetime and reliability of the used light source.
Tutor: Horský Jaroslav, prof. Ing., CSc.
Over the recent years, a special type of plastic material with high thermal conductivity can be found on the market, which could be used in the design of the cooling system of automotive light sources. It could offer such benefits as design freedom for various applications and lower costs. Because it is a new material, it will be necessary to determine the thermo-physical properties and develop a methodology which can evaluate the suitability of the design of cooling.
Study plan wasn't generated yet for this year.