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Rigid particles in a Stokesian fluid experience an increasingly strong lubrication resistance as particle gaps narrow. Numerically, resolving these lubrication forces comes at an intractably large cost, even for moderate system sizes. Hence, it can typically not be guaranteed that artificial particle collisions and overlaps do not occur in a dynamic simulation, independently of the choice of method to solve the Stokes equations. In this work, the potentially large set of non-overlap constraints, in terms of the Euclidean distance between boundary points on disjoint particles, are efficiently represented via a barrier energy. We solve for the minimum magnitudes of repelling contact forces and torques between any particle pair in contact to correct for overlaps by enforcing a zero barrier energy at the next time level, given a contact-free configuration at a previous instance in time. Robustness for the method is illustrated using a multiblob method to solve the mobility problem in Stokes flow, applied to suspensions of spheres, rods and boomerang shaped particles. Collision free configurations are obtained at all instances in time, and considerably larger time-steps can be taken than without the technique. The effect of the contact forces on the collective order of a set of rods in a background flow that naturally promote particle interactions is also illustrated., QC 20231205

Rigid particles in a Stokesian fluid experience an increasingly strong lubrication resistance as particle gaps narrow. Numerically, resolving these lubrication forces comes at an intractably large cost, even for moderate system sizes. Hence, it can typically not be guaranteed that artificial particle collisions and overlaps do not occur in a dynamic simulation, independently of the choice of method to solve the Stokes equations. In this work, the potentially large set of non-overlap constraints, in terms of the Euclidean distance between boundary points on disjoint particles, are efficiently represented via a barrier energy. We solve for the minimum magnitudes of repelling contact forces and torques between any particle pair in contact to correct for overlaps by enforcing a zero barrier energy at the next time level, given a contact-free configuration at a previous instance in time. Robustness for the method is illustrated using a multiblob method to solve the mobility problem in Stokes flow, applied to suspensions of spheres, rods and boomerang shaped particles. Collision free configurations are obtained at all instances in time, and considerably larger time-steps can be taken than without the technique. The effect of the contact forces on the collective order of a set of rods in a background flow that naturally promote particle interactions is also illustrated., QC 20231205

Rigid particles in a Stokesian fluid experience an increasingly strong lubrication resistance as particle gaps narrow. Numerically, resolving these lubrication forces comes at an intractably large cost, even for moderate system sizes. Hence, it can typically not be guaranteed that artificial particle collisions and overlaps do not occur in a dynamic simulation, independently of the choice of method to solve the Stokes equations. In this work, the potentially large set of non-overlap constraints, in terms of the Euclidean distance between boundary points on disjoint particles, are efficiently represented via a barrier energy. We solve for the minimum magnitudes of repelling contact forces and torques between any particle pair in contact to correct for overlaps by enforcing a zero barrier energy at the next time level, given a contact-free configuration at a previous instance in time. Robustness for the method is illustrated using a multiblob method to solve the mobility problem in Stokes flow, applied to suspensions of spheres, rods and boomerang shaped particles. Collision free configurations are obtained at all instances in time, and considerably larger time-steps can be taken than without the technique. The effect of the contact forces on the collective order of a set of rods in a background flow that naturally promote particle interactions is also illustrated., QC 20231205

Rigid particles in a Stokesian fluid experience an increasingly strong lubrication resistance as particle gaps narrow. Numerically, resolving these lubrication forces comes at an intractably large cost, even for moderate system sizes. Hence, it can typically not be guaranteed that artificial particle collisions and overlaps do not occur in a dynamic simulation, independently of the choice of method to solve the Stokes equations. In this work, the potentially large set of non-overlap constraints, in terms of the Euclidean distance between boundary points on disjoint particles, are efficiently represented via a barrier energy. We solve for the minimum magnitudes of repelling contact forces and torques between any particle pair in contact to correct for overlaps by enforcing a zero barrier energy at the next time level, given a contact-free configuration at a previous instance in time. Robustness for the method is illustrated using a multiblob method to solve the mobility problem in Stokes flow, applied to suspensions of spheres, rods and boomerang shaped particles. Collision free configurations are obtained at all instances in time, and considerably larger time-steps can be taken than without the technique. The effect of the contact forces on the collective order of a set of rods in a background flow that naturally promote particle interactions is also illustrated., QC 20231205

Journal bearings in typical applications are subjected to misalignment due to several causes, such as shaft deformation under load and errors related to the installation and manufacturing processes. Misalignment has well-known severe negative consequences on the performance of the bearings. This paper deals with the bearing chamfer to reduce these consequences of misalignment, and two forms of bearing edge modification are considered in the analysis. These forms are linear and curved chamfering of the bearing edges, where the height of the chamfer in the circumferential direction and the length of the modification in the longitudinal direction are considered as geometrical design parameters. The investigation includes a numerical solution of the hydrodynamic lubrication problem of finite length journal bearing, considering 3D misalignment cases using the finite difference method. This includes the assessment of the chamfer forms and their effects on the bearing performance in terms of the main bearing design parameters. Furthermore, the stability of the chamfered bearings is also investigated under impact load. Results showed that both chamfer forms are beneficial for a certain limit of the design parameters in reducing the maximum pressure and coefficient of friction and in elevating the film thickness levels, extending the range of misalignment in which the journal bearing can operate safely. In addition, the chamfered bearings in both forms showed more stability range in terms of the critical speed and shaft center trajectories under impact load. The bearings with the curved chamfer, where the slope is continuous at the start of modification, showed more uniform film thickness levels, and their shaft center trajectories were closer to the perfectly aligned bearing in the stable operating range of the system., Journal bearings in typical applications are subjected to misalignment due to several causes, such as shaft deformation under load and errors related to the installation and manufacturing processes. Misalignment has well-known severe negative consequences on the performance of the bearings. This paper deals with the bearing chamfer to reduce these consequences of misalignment, and two forms of bearing edge modification are considered in the analysis. These forms are linear and curved chamfering of the bearing edges, where the height of the chamfer in the circumferential direction and the length of the modification in the longitudinal direction are considered as geometrical design parameters. The investigation includes a numerical solution of the hydrodynamic lubrication problem of finite length journal bearing, considering 3D misalignment cases using the finite difference method. This includes the assessment of the chamfer forms and their effects on the bearing performance in terms of the main bearing design parameters. Furthermore, the stability of the chamfered bearings is also investigated under impact load. Results showed that both chamfer forms are beneficial for a certain limit of the design parameters in reducing the maximum pressure and coefficient of friction and in elevating the film thickness levels, extending the range of misalignment in which the journal bearing can operate safely. In addition, the chamfered bearings in both forms showed more stability range in terms of the critical speed and shaft center trajectories under impact load. The bearings with the curved chamfer, where the slope is continuous at the start of modification, showed more uniform film thickness levels, and their shaft center trajectories were closer to the perfectly aligned bearing in the stable operating range of the system.

Актуальність даної роботи полягає в тому, що в умовах інтенсифікації виробництва необхідно при швидких темпах виробництва забезпечити високу якість складання кривошипно-планетарного редуктора, значно зменшивши при цьому затрати часового ресурсу. Мета дослідження полягає в розробці методики розрахунку характеристик якості складання кривошипно-планетарних редукторів на основі отриманих математичних моделей. Задачами магістерської дисертації є: - Виконати аналіз конструктивних рішень редукторів; - Визначити основні конструкторсько-технологічні особливості. Які впливають на якість виготовлення редукторів; - Виконати моделювання основних характеристик якості кривошипно-планетарно редуктора (КПР); - Розробити алгоритмічне і програмне забезпечення, що дозволить виконати розрахунок основних характеристик якості складання КПР в автоматизованому режимі. Об’єктом дослідження: Характеристики якості складання редукторів. Предмет дослідження: Кривошипно-планетарний редуктор. Наукова новизна: - Розроблена методика розрахунку контактних напружень в механізмах з паралелограмним механізмом зняття обертового руху з сателітів; - Виведено рівняння умови співвісності; - Розроблена методика визначення умови самогальмування кривошипно-планетарного редуктора. Практична цінність реалізації роботи. Запропоновано нову спрощену конструкцію симетричного кривошипно-планетарного редуктора з наскрізним вхідним валом, що дає можливість як пропускати різноманітні комунікації, так і реалізувати для даного редуктора дві степені вільності. При чому корпус редуктора передбачає можливість використання редуктора у якості сателітного механізму з двома ступенями вільності, а конструкція редуктора у цілому є симетричною, в т.ч. за приєднувальними розмірами, що дає змогу суттєво розширити область застосувань даного редуктора. Новизна даного технічного рішення підтверджується поданням заявки на видачу патенту України на корисну модель. Номер заявки: u 2018 10964. Розроблено програмне забезпечення для розрахунку, The urgency of this work is that in conditions of intensification of production it is necessary at a fast pace of production to ensure the high quality of the assembly of the crank-planetary gear, significantly reducing the cost of time resources. The purpose of the study is to develop a methodology for calculating the characteristics of the quality of assembly of crank-planetary reducers on the basis of the obtained mathematical models. The objectives of the master's thesis are: - To carry out the analysis of constructive decisions of reducers; - Identify the main design and technological features. What affects the quality of the manufacture of gearboxes; - Perform the simulation of the main characteristics of the crank - planetary gearbox (CRC) quality; - To develop algorithmic and software that will allow to calculate the main characteristics of the quality of compilation of CRC in automated mode. Object of research: Characteristic s of quality of assembly of reducers. Subject of study: Crankshaft - planetary reducer. Scientific novelty: - The method of calculation of contact stresses in mechanisms with parallelogram mechanism of removal of rotary motion from satellites is developed; - The equation of the congruence condition is derived; - A method for determining the self - immobilization condition of a crank - planetary reducer is developed. The practical value of the implementation of the work. A new simplified design of a symmetrical crank - planetary gearbox with a through - pass input shaft is proposed, which enables both the passage of various communications, and to realize two degrees of freedom for a given gearbox. Moreover, the gearbox housing allows the use of the gearbox as a satellite mechanism with two degrees of freedom, and the design of the gearbox as a whole is symmetrical, including according to the connecting dimensions, which allows to significantly expand the range of applications of this gearbox. The novelty of this technical solution is co

[EN] The variation of the interaction force between the pantograph and the railway catenary determines the quality of the electric current catchment of this system. That variation can be estimated as of the dynamic simulation of the contact problem due to the interaction between the pantograph and the railway catenary. The main objetive of this paper is to analyse the results for five real catenaries. After the imposition of the required data and parameters that define the finite elements model of the catenary, as well as the dynamic variables of the problem, the non-lineal dynamic problem is solved in different speeds of circulation, for every catenary proposed. By using optimization genetic algorithms, it is expected to minimize the typical deviation of the obtained contact force in the simulations, which is the objetive function of the problem, as it represents the main parameter determining the quality of electric current catchment. At the same time, the obtained results will be evaluated in order to compare them between the nominal and optimized configuration. These results attend the contact force versus time and speed, the typical deviation of this force and finally the maximum vertical displacement for the central post of the catenary. The variables considered in the optimization process are susceptible to be modified in the real catenaries, like the position or length of the droppers. The finite elements model has been developed in the Mechanical and Materials Engineering Department at Universidad Politécnica de Valencia and the start point is the dynamic formulation of the problem commented as well as the genetic algorithm in Matlab being carried out in the Department. Consequently, this paper has the intention of validate the methods of study of the problem regarding the interaction between the pantograph and the system comprised by the railway catenary. The Master Thesis then verify and test the existent procedures to study this dynamic phenomena and it, [ES] La variación de la fuerza de interacción entre el pantógrafo y la catenaria ferroviaria es un factor que determina la calidad de captación de corriente de este sistema. Esa variación se puede estimar a partir de la simulación dinámica del problema de contacto debido a la interacción entre pantógrafo y catenaria ferroviaria. En el presente Trabajo Fin de Máster se han simulado y analizado los resultados que se obtienen de dicho problema dinámico con el objetivo de poder analizar cinco líneas aéreas reales. Tras imponer los parámetros necesarios que definen el modelo de elementos finitos de la catenaria así como las variables dinámicas del problema, se resuelve el problema dinámico no lineal a diversas velocidades de simulación para todas las catenarias propuestas. El objetivo pues del trabajo es optimizar la geometría de las catenarias para obtener un funcionamiento más satisfactorio del sistema simulado. Con ello se pretende mediante el uso de algoritmos genéticos de optimización minimizar la desviación típica de la fuerza de contacto obtenida en la simulación, que será la función objetivo de dicho algoritmo por ser el parámetro que determina de una forma más relevante la calidad de la captación de corriente. Al mismo tiempo se pretenden evaluar los resultados hallados en las mismas condiciones de cálculo para las catenarias tras la optimización, para poder comparar resultados. Estos resultados son las fuerzas de contacto obtenidas frente al tiempo y velocidad, la desviación típica de dicha fuerza de contacto además de los desplazamientos verticales máximos del brazo de registro central de la catenaria. Las optimizaciones se formulan tomando como variable parámetros que son susceptibles de modificarse en la realidad, como la posición y longitudes de las péndolas del vano. El modelo de elementos finitos de la catenaria se ha desarrollado en el Departamento de Ingeniería Mecánica y de Materiales de la Universidad Politécnica de Valencia y al mismo tiempo se parte, [CA] La variació de la força d'interacció entre el pantògraf i la catenària ferroviària és un factor que determina la qualitat de captació de corrent d'aquest sistema. Aquesta variació es pot estimar a partir de la simulació dinàmica del problema de contacte a causa de la interacció entre pantògraf i catenària ferroviària. En el present Treball Fi de Màster s'han simulat i analitzat els resultats que s'obtenen d'aquest problema dinàmic amb l'objectiu de poder analitzar cinc línies aèries reals. Després imposar els paràmetres necessaris que defineixen el model d'elements finits de la catenària així com les variables dinàmiques del problema, es resol el problema dinàmic no lineal a diverses velocitats de simulació per a totes les catenàries propostes. L'objectiu doncs del treball és optimitzar la geometria de les catenàries per obtenir un funcionament més satisfactori del sistema simulat. Amb això es pretén mitjançant l'ús d'algoritmes genètics d'optimització minimitzar la desviació típica de la força de contacte obtinguda en la simulació, que serà la funció objectiu d'aquest algoritme per ser el paràmetre que determina d'una manera més rellevant la qualitat de la captació de corrent. Alhora es pretenen avaluar els resultats trobats en les mateixes condicions de càlcul per a les catenàries després de la optimització, per poder comparar resultats. Aquests resultats són les forces de contacte obtingudes enfront del temps i velocitat, la desviació típica d'aquesta força de contacte a més dels desplaçaments verticals màxims del braç de registre central de la catenària. Les optimitzacions es formulen prenent com a variable paràmetres que són susceptibles de modificar-se en la realitat, com la posició i longituds de les pèndoles del va. El model d'elements finits de la catenària s'ha desenvolupat en el Departament d'Enginyeria Mecànica i de Materials de la Universitat Politècnica de València i al mateix temps es parteix dels desenvolupaments efectuats en aquest departament

[EN] The variation of the interaction force between the pantograph and the railway catenary determines the quality of the electric current catchment of this system. That variation can be estimated as of the dynamic simulation of the contact problem due to the interaction between the pantograph and the railway catenary. The main objetive of this paper is to analyse the results for five real catenaries. After the imposition of the required data and parameters that define the finite elements model of the catenary, as well as the dynamic variables of the problem, the non-lineal dynamic problem is solved in different speeds of circulation, for every catenary proposed. By using optimization genetic algorithms, it is expected to minimize the typical deviation of the obtained contact force in the simulations, which is the objetive function of the problem, as it represents the main parameter determining the quality of electric current catchment. At the same time, the obtained results will be evaluated in order to compare them between the nominal and optimized configuration. These results attend the contact force versus time and speed, the typical deviation of this force and finally the maximum vertical displacement for the central post of the catenary. The variables considered in the optimization process are susceptible to be modified in the real catenaries, like the position or length of the droppers. The finite elements model has been developed in the Mechanical and Materials Engineering Department at Universidad Politécnica de Valencia and the start point is the dynamic formulation of the problem commented as well as the genetic algorithm in Matlab being carried out in the Department. Consequently, this paper has the intention of validate the methods of study of the problem regarding the interaction between the pantograph and the system comprised by the railway catenary. The Master Thesis then verify and test the existent procedures to study this dynamic phenomena and it, [ES] La variación de la fuerza de interacción entre el pantógrafo y la catenaria ferroviaria es un factor que determina la calidad de captación de corriente de este sistema. Esa variación se puede estimar a partir de la simulación dinámica del problema de contacto debido a la interacción entre pantógrafo y catenaria ferroviaria. En el presente Trabajo Fin de Máster se han simulado y analizado los resultados que se obtienen de dicho problema dinámico con el objetivo de poder analizar cinco líneas aéreas reales. Tras imponer los parámetros necesarios que definen el modelo de elementos finitos de la catenaria así como las variables dinámicas del problema, se resuelve el problema dinámico no lineal a diversas velocidades de simulación para todas las catenarias propuestas. El objetivo pues del trabajo es optimizar la geometría de las catenarias para obtener un funcionamiento más satisfactorio del sistema simulado. Con ello se pretende mediante el uso de algoritmos genéticos de optimización minimizar la desviación típica de la fuerza de contacto obtenida en la simulación, que será la función objetivo de dicho algoritmo por ser el parámetro que determina de una forma más relevante la calidad de la captación de corriente. Al mismo tiempo se pretenden evaluar los resultados hallados en las mismas condiciones de cálculo para las catenarias tras la optimización, para poder comparar resultados. Estos resultados son las fuerzas de contacto obtenidas frente al tiempo y velocidad, la desviación típica de dicha fuerza de contacto además de los desplazamientos verticales máximos del brazo de registro central de la catenaria. Las optimizaciones se formulan tomando como variable parámetros que son susceptibles de modificarse en la realidad, como la posición y longitudes de las péndolas del vano. El modelo de elementos finitos de la catenaria se ha desarrollado en el Departamento de Ingeniería Mecánica y de Materiales de la Universidad Politécnica de Valencia y al mismo tiempo se parte, [CA] La variació de la força d'interacció entre el pantògraf i la catenària ferroviària és un factor que determina la qualitat de captació de corrent d'aquest sistema. Aquesta variació es pot estimar a partir de la simulació dinàmica del problema de contacte a causa de la interacció entre pantògraf i catenària ferroviària. En el present Treball Fi de Màster s'han simulat i analitzat els resultats que s'obtenen d'aquest problema dinàmic amb l'objectiu de poder analitzar cinc línies aèries reals. Després imposar els paràmetres necessaris que defineixen el model d'elements finits de la catenària així com les variables dinàmiques del problema, es resol el problema dinàmic no lineal a diverses velocitats de simulació per a totes les catenàries propostes. L'objectiu doncs del treball és optimitzar la geometria de les catenàries per obtenir un funcionament més satisfactori del sistema simulat. Amb això es pretén mitjançant l'ús d'algoritmes genètics d'optimització minimitzar la desviació típica de la força de contacte obtinguda en la simulació, que serà la funció objectiu d'aquest algoritme per ser el paràmetre que determina d'una manera més rellevant la qualitat de la captació de corrent. Alhora es pretenen avaluar els resultats trobats en les mateixes condicions de càlcul per a les catenàries després de la optimització, per poder comparar resultats. Aquests resultats són les forces de contacte obtingudes enfront del temps i velocitat, la desviació típica d'aquesta força de contacte a més dels desplaçaments verticals màxims del braç de registre central de la catenària. Les optimitzacions es formulen prenent com a variable paràmetres que són susceptibles de modificar-se en la realitat, com la posició i longituds de les pèndoles del va. El model d'elements finits de la catenària s'ha desenvolupat en el Departament d'Enginyeria Mecànica i de Materials de la Universitat Politècnica de València i al mateix temps es parteix dels desenvolupaments efectuats en aquest departament

[EN] The variation of the interaction force between the pantograph and the railway catenary determines the quality of the electric current catchment of this system. That variation can be estimated as of the dynamic simulation of the contact problem due to the interaction between the pantograph and the railway catenary. The main objetive of this paper is to analyse the results for five real catenaries. After the imposition of the required data and parameters that define the finite elements model of the catenary, as well as the dynamic variables of the problem, the non-lineal dynamic problem is solved in different speeds of circulation, for every catenary proposed. By using optimization genetic algorithms, it is expected to minimize the typical deviation of the obtained contact force in the simulations, which is the objetive function of the problem, as it represents the main parameter determining the quality of electric current catchment. At the same time, the obtained results will be evaluated in order to compare them between the nominal and optimized configuration. These results attend the contact force versus time and speed, the typical deviation of this force and finally the maximum vertical displacement for the central post of the catenary. The variables considered in the optimization process are susceptible to be modified in the real catenaries, like the position or length of the droppers. The finite elements model has been developed in the Mechanical and Materials Engineering Department at Universidad Politécnica de Valencia and the start point is the dynamic formulation of the problem commented as well as the genetic algorithm in Matlab being carried out in the Department. Consequently, this paper has the intention of validate the methods of study of the problem regarding the interaction between the pantograph and the system comprised by the railway catenary. The Master Thesis then verify and test the existent procedures to study this dynamic phenomena and it, [ES] La variación de la fuerza de interacción entre el pantógrafo y la catenaria ferroviaria es un factor que determina la calidad de captación de corriente de este sistema. Esa variación se puede estimar a partir de la simulación dinámica del problema de contacto debido a la interacción entre pantógrafo y catenaria ferroviaria. En el presente Trabajo Fin de Máster se han simulado y analizado los resultados que se obtienen de dicho problema dinámico con el objetivo de poder analizar cinco líneas aéreas reales. Tras imponer los parámetros necesarios que definen el modelo de elementos finitos de la catenaria así como las variables dinámicas del problema, se resuelve el problema dinámico no lineal a diversas velocidades de simulación para todas las catenarias propuestas. El objetivo pues del trabajo es optimizar la geometría de las catenarias para obtener un funcionamiento más satisfactorio del sistema simulado. Con ello se pretende mediante el uso de algoritmos genéticos de optimización minimizar la desviación típica de la fuerza de contacto obtenida en la simulación, que será la función objetivo de dicho algoritmo por ser el parámetro que determina de una forma más relevante la calidad de la captación de corriente. Al mismo tiempo se pretenden evaluar los resultados hallados en las mismas condiciones de cálculo para las catenarias tras la optimización, para poder comparar resultados. Estos resultados son las fuerzas de contacto obtenidas frente al tiempo y velocidad, la desviación típica de dicha fuerza de contacto además de los desplazamientos verticales máximos del brazo de registro central de la catenaria. Las optimizaciones se formulan tomando como variable parámetros que son susceptibles de modificarse en la realidad, como la posición y longitudes de las péndolas del vano. El modelo de elementos finitos de la catenaria se ha desarrollado en el Departamento de Ingeniería Mecánica y de Materiales de la Universidad Politécnica de Valencia y al mismo tiempo se parte, [CA] La variació de la força d'interacció entre el pantògraf i la catenària ferroviària és un factor que determina la qualitat de captació de corrent d'aquest sistema. Aquesta variació es pot estimar a partir de la simulació dinàmica del problema de contacte a causa de la interacció entre pantògraf i catenària ferroviària. En el present Treball Fi de Màster s'han simulat i analitzat els resultats que s'obtenen d'aquest problema dinàmic amb l'objectiu de poder analitzar cinc línies aèries reals. Després imposar els paràmetres necessaris que defineixen el model d'elements finits de la catenària així com les variables dinàmiques del problema, es resol el problema dinàmic no lineal a diverses velocitats de simulació per a totes les catenàries propostes. L'objectiu doncs del treball és optimitzar la geometria de les catenàries per obtenir un funcionament més satisfactori del sistema simulat. Amb això es pretén mitjançant l'ús d'algoritmes genètics d'optimització minimitzar la desviació típica de la força de contacte obtinguda en la simulació, que serà la funció objectiu d'aquest algoritme per ser el paràmetre que determina d'una manera més rellevant la qualitat de la captació de corrent. Alhora es pretenen avaluar els resultats trobats en les mateixes condicions de càlcul per a les catenàries després de la optimització, per poder comparar resultats. Aquests resultats són les forces de contacte obtingudes enfront del temps i velocitat, la desviació típica d'aquesta força de contacte a més dels desplaçaments verticals màxims del braç de registre central de la catenària. Les optimitzacions es formulen prenent com a variable paràmetres que són susceptibles de modificar-se en la realitat, com la posició i longituds de les pèndoles del va. El model d'elements finits de la catenària s'ha desenvolupat en el Departament d'Enginyeria Mecànica i de Materials de la Universitat Politècnica de València i al mateix temps es parteix dels desenvolupaments efectuats en aquest departament

Проблематика. Розглянуто питання розрахунку контактної сили в паралелограмному механізмі зняття обертального руху із сателітів кривошипно-планетарного редуктора залежно від кута повороту його ексцен­три­ко­вого вала.Мета дослідження. Розробка методики розрахунку контактної сили в паралелограмному механізмі залежно від кута повороту ексцентрикового вала редуктора і встановлення максимального її значення. Максимальне зна­чен­ня сили визначає максимальні напруження деталей механізму, а отже, і міцність редуктора в цілому.Методика реалізації. На першому етапі на основі формул аналітичної геометрії контактні пари паралелограм­но­го механізму класифіковано на ведучі (активні) та пасивні. На другому етапі наведено методику розрахунку контактної сили в активних контактних парах, яка побудована на засадах принципу можливих переміщень у рамках припущення про квазістатичний режим роботи кривошипно-планетарного редуктора. При обчис­лен­ні максимальних напружень у контактних парах застосовна класична формула для циліндричних поверхонь.Результати дослідження. Виведено формулу, яка дає змогу встановити номери ведучих контактних пар при заданому положенні ексцентикового вала кривошипно-планетарного редуктора. Отримано циклограму кон­так­т­ної сили в кожній контактній парі. Представлено формулу для визначення наближеного максимального значення контактної сили в контактних парах, яка справедлива для редукторів із кількістю таких пар від 3 до 10.Висновки. Надано результати розробленої методики розрахунку редукторів із пралелограмним механізмом зняття обертового руху із сателітів. З’ясовано, що при проектуванні редукторів із пралелограмним меха­ніз­мом зняття обертального руху із сателітів актуальними є питання забезпечення динамічної міцності його деталей. При перевірці контактної міцності або міцності при згинанні в зубчастому зачепленні застосовні класичні ме­тоди розрахунку. У той же час при оцінці міцності сателіта в місці контакту з цівками вихідної ланки ре­дук­тора може бути за, Проблематика. Рассмотрены вопросы расчета контактной силы в параллелограммном механизме снятия вращательного движения с сателлитов в кривошипно-планетарном редукторе в зависимости от угла поворота эксцентрикового вала редуктора.Цель исследования. Целью работы является разработка методики расчета контактной силы в параллелограммном механизме в зависимости от угла поворота эксцентрикового вала редуктора и определение максимального ее значения. Максимальное значение силы определяет максимальные напряжения деталей механизма, а следовательно, и прочность редуктора в целом.Методика реализации. На первом этапе на основе формул аналитической геометрии контактные пары параллелограммного механизма классифицированы на ведущие (активные) и пассивные. На втором этапе приведена методика расчета контактной силы в активных контактных парах, которая построена на основе принципа возможных перемещений в рамках предположения о квазистатическом режиме работы кривошипно-планетарного редуктора. При расчете максимальных напряжений в контактных парах применима классическая формула для цилиндрических поверхностей.Результаты исследования. Выведена формула, которая позволяет установить номера ведущих контактных пар при заданном положении эксцентрикового вала кривошипно-планетарного редуктора. Получена циклограмма контактной силы в каждой контактной паре. Представлена формула для определения приближенного максимального значения контактной силы в контактных парах, которая справедлива для редукторов с количеством таких пар от 3 до 10.Выводы. Представлены результаты разработанной методики расчета редукторов с параллелограммным механизмом снятия вращательного движения с сателлитов. Выяснено, что при проектировании редукторов с параллелограммным механизмом снятия вращательного движения с сателлитов актуальными являются вопросы обеспечения динамической прочности его деталей. При проверке контактной прочности или прочности при изгибе в зубчатом зацеплении применимы классические методы расчета. В то же, Background. The problem of calculating the contact force in the parallelogram mechanism for taking the rotary motion from satellites in the crank-planetary gearbox, depending on the angle of rotation of the eccentric shaft of the gearbox, is considered.Objective. The aim of the paper is to develop a method for calculating the contact force in the parallelogram mechanism, depending on the rotation angle of the gear unit eccentric shaft and determination of its maximum value. The maximum force value determines the maximum stresses of the mechanism parts, and, consequently, the strength of the gear unit as a whole.Methods. In the first stage, on the basis of formulas of analytical geometry, the contact pairs of the parallelogram mechanism are classified on leading (active) and passive. In the second stage, the method of calculating the contact force in active contact pairs is given. This method is based on the principle of possible displacements in the framework of the assumption about the quasi-static operation mode of the crank-planetary reducer. When calculating the maximum stresses in contact pairs the classical formula for cylindrical surfaces can be applied.Results. A formula is derived that allows you to set the numbers of leading contact pairs at a given position of the crank-planetary reducer's eccentric shaft. The resulting graph of the contact force in each contact pair is obtained. The formula for determining the approximate maximum value of the contact force in contact pairs is presented, which is valid for reducers with the number of such pairs from 3 to 10.Conclusions. The results of the developed method of calculation of reducers with the parallelogram mechanism for taking the rotary motion from the satellites are presented. It was found out that when designing gears with a parallelogram mechanism for taking the rotary motion from satellites, the issues of ensuring the dynamic strength of its parts are relevant. When checking the contact strength or ben

type:Conference Paper, The green house is often used to add the quality and value of agricultural products. Newly developed full open type green house has a lot of attracted attention whose roof opens and closes automatically in order to control the temperature. However, since the roof opens and closes very often, the cover sheet can be used only for 3-4 months. This is because the plastic film is damaged between the support pipe and rolling pipe during opening-closing affected by fatigue and wear. In this study, the damage mechanism is investigated for the several plastic films used for the full open type green house. In the first place, FEM analysis is performed to evaluate the damage of plastic film between pipes under different film materials. Here, the maximum contact pressure and thickness reduction are analysed under static contact analysis and rolling contact analysis as the most important factors. Finally, rolling fatigue experiment is performed to investigate the damage with changing plastic films. Then, the results are compared with the FEM analysis., 3rd International Conference on Fracture Fatigue and Wear, FFW2014, Kitakyushu, Japan, 1-3 September 2014

[EN] In breast cancer screening or diagnosis, it is usual to combine different images in order to locate a lesion as accurately as possible. These images are generated using a single or several imaging techniques. As x-ray-based mammography is widely used, a breast lesion is located in the same plane of the image (mammogram), but tracking it across mammograms corresponding to different views is a challenging task for medical physicians. Accordingly, simulation tools and methodologies that use patient-specific numerical models can facilitate the task of fusing information from different images.Additionally, these tools need to be as straightforward as possible to facilitate their translation to the clinical area. This paper presents a patient-specific, finite-element-based and semi-automated simulation methodology to track breast lesions across mammograms. A realistic three-dimensional computer model of a patient¿s breast was generated from magnetic resonance imaging to simulate mammographic compressions in cranio-caudal (CC, head-to-toe) and medio-lateral oblique (MLO, shoulder-to-opposite hip) directions. For each compression being simulated, a virtual mammogram was obtained and posteriorly superimposed to the corresponding real mammogram, by sharing the nipple as a common feature. Two-dimensional rigid-body transformations were applied, and the error distance measured between the centroids of the tumors previously located on each image was 3.84 mm and 2.41 mm for CC and MLO compression, respectively. Considering that the scope of this work is to conceive a methodology translatable to clinical practice, the results indicate that it could be helpful in supporting the tracking of breast lesions.

In the paper, a computational model for the transient response of laminated composite and sandwich plates with existing zones of partial delamination, subjected to dynamic pulse loading is proposed. Laminated composite and sandwich plates are modeled using the extended version of the Generalized Laminated Plate Theory. For the numerical solution, the finite element method with layered finite elements is used. Delamination between individual layers is considered as discontinuities in the displacement field using Heaviside step functions. Since the status of delaminated layers may change in dynamic loading conditions, leading to the so-called "breathing" phenomenon, contact conditions allowing for the opening/closing of delaminated layers are proposed. Nonlinear kinematics in the sense of small strains and moderately large rotations is accounted for according to the von Karman assumptions. The material of the individual layers is assumed as orthotropic and linearly elastic. The governing spatial temporal partial differential equations are integrated in time by means of the implicit Newmarlc's method. After verification of the proposed model for intact plates, the effect of the size and the position of embedded delamination zones on the transient response of geometrical nonlinearity of composite and sandwich plates is investigated numerically by means of a number of numerical applications.

In the paper, a computational model for the transient response of laminated composite and sandwich plates with existing zones of partial delamination, subjected to dynamic pulse loading is proposed. Laminated composite and sandwich plates are modeled using the extended version of the Generalized Laminated Plate Theory. For the numerical solution, the finite element method with layered finite elements is used. Delamination between individual layers is considered as discontinuities in the displacement field using Heaviside step functions. Since the status of delaminated layers may change in dynamic loading conditions, leading to the so-called "breathing" phenomenon, contact conditions allowing for the opening/closing of delaminated layers are proposed. Nonlinear kinematics in the sense of small strains and moderately large rotations is accounted for according to the von Karman assumptions. The material of the individual layers is assumed as orthotropic and linearly elastic. The governing spatial temporal partial differential equations are integrated in time by means of the implicit Newmarlc's method. After verification of the proposed model for intact plates, the effect of the size and the position of embedded delamination zones on the transient response of geometrical nonlinearity of composite and sandwich plates is investigated numerically by means of a number of numerical applications.

When implementing variational methods for solving complex contact problems, there are difficulties, associated with non-convexity of minimized energy function of the system of interacting bodies and non-differentiability of this function at the desired point of its minimum. These difficulties do not allow to use gradient methods and convex analysis methods to minimize the energy function, therefore, numerical procedures for finding minimum points of such functions are cumbersome in program implementation and sometimes make it impossible to obtain the contact problem solution with sufficient accuracy. Non-variational method, based on using nonlinear operator equations with no difficulties during its implementation is proposed in the paper. Applying these equations allows to use modern achievements of nonlinear functional analysis, fixed-point theory of continuous mappings, theory of iterative methods for solving operator equations for both proving theorems of existence of solutions to contact problems, and developing effective iterative procedures for approximate solutions. Nonlinear boundary integral equations, used in this paper to simulate the contact interaction of elastic bodies, allow (unlike other similar equations) to take into account both the linkage and partial slip on the contact surface of bodies, and loading history of these bodies. Based on these equations, simple and efficient iterative procedures for approximate solutions to the contact problems are developed. A numerical solution of the contact problem on indenting the elastic sphere in the elastic half-space is obtained, and comparison of results with the known problem solution is made., Предложен метод приближенного решения пространственной задачи о контакте линейно-упругих тел с учетом кулонова трения и истории приложения внешней нагрузки. Отличительная особенность метода состоит в том, что рассматриваемая контактная задача сводится к последовательному решению нескольких систем граничных нелинейных интегральных уравнений, которые соответствуют различным шагам нагружения. Получено численное решение задачи о контактном взаимодействии упругого шара с упругим полупространством., Запропоновано метод наближеного розв’язування просторової задачі про контакт лінійно-пружних тіл з урахуванням тертя Кулона та історії прикладання зовнішнього навантаження. Відмітна особливість методу полягає в тому, що розглядувану контактну задачу зведено до послідовного розв’язання низки систем межових нелінійних інтегральних рівнянь, які відповідають різним крокам навантажування. Отримано чисельний розв’язок задачі про контактну взаємодію пружної кулі з пружним півпростором.

The self-loosening mechanisms of a bolted joint subjected to a rotational load were investigated using three-dimensional FEM. A previous theory regarding the conditions of initiation and progress of loosening was verified. Loosening occurs if the relative rotation angle applied to the bolt reaches a critical value . Ξ cr and the thread surface undergoes a complete slip. In addition, loosening progresses if . T sl<. T w<. T st holds, where . T sl, . T st, and . T w are the loosening and the tightening torque of the thread surface, and the slip torque of the bearing surface, respectively. If above conditions hold, bolt tension decreases in proportion to the relative rotation angle of the bolt during complete thread-surface slip while bolt tension does not change during complete bearing-surface slip. If these conditions do not hold, loosening does not progress even if the thread or the bearing surface undergoes complete slip. In order to verify the above loosening mechanism, a loosening test was carried out. It was confirmed that the loosening progressed by the same mechanism as that shown by FEM., QC 20120529

This paper considers a computation method in failure analysis of layered composites containing pin-loaded holes. The investigation is focused on developing a reliable computation procedure to analyze initial failure load for pin-loaded holes at layered composite structures. Finite element method (FEM) is used to determine stress distribution around the fastener hole. Combining Chang-Scott-Springer characteristic curve model and Tsai-Wu initial failure criterion are used to determine joint failure. Special attention in this work is paid to pin-load distributions and its effect on the load level of failure and its location. In previous work initial failure analysis was carried out using cosine distribution between pin/lug mechanically fastened joint. Here contact finite element pin/lug model is analysed. The influence of stacking sequences of layered composites containing pin-loaded holes is also investigated. Special attention is paid to failure load and mode analyses in composites with stacking sequence [0/(+/-45)(3)/90(3)](s). The computation results are compared with available experimental results. Good correlations between computation and experimental results are obtained.

This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The critical internal pressure for leak in the sealing performance of this system is investigated through an experiment and FEM analysis with varying flange nominal size. The analysis indicates that the critical pressure is controlled by the maximum contact stress appearing at the highest point of the annular lip when the flanges are assembled even the flange nominal sizes are different.

This paper deals with a new seal system between two flanges without using gaskets. The system includes a groove and an annular lip that is held by one of the flange with its highest point in contact with the other flange to form a seal line when the flanges are assembled. The condition whether the system leaks or not depends on the shape and dimension of the thinned area with the annular lip deformed during the contact. In this study several gasketless flanges are prepared with varing the fundamental dimensions of the flange to investigate the condition through an experimental and FEM analysis. The analysis indicates that the conditions can be expressed in terms of the maximum contact stress and the plastic zone size when the flanges are assembled.

This paper deals with a new seal system between flange joints without using gasket. This gasketless flange includes a groove and an annular lip that is machined in one of the flange being in contact with the other flange to form a seal line when the flanges are assembled. In this study, first, fundamental dimensions are examined for PVC-U to obtain the best sealing performance. Then, the effects of material difference and flange nominal size on the sealing performance of new gasketless flange are investigated for two types of materials, 0.25% carbon steel (S25C JIS) and unplasticized polyvinyl chloride (PVC-U JIS). It is found that the critical internal pressure where leakage appears is mainly controlled by the maximum normal stress at the annular lip for each material even if the flange nominal sizes are different. The gasketless flange made by PVC-U shows the higher critical internal pressure compared with the case of S25C if the same clamping forces are applied. The effect of stress relaxation for PVC-U on the sealing performance is also considered. Then, it may be concluded that this PVC-U gasketless flange also has good sealing performance.

A design method is proposed of a master-slave system executing a continuous contact task with high maneuverability. We introduce a variable viscosity-ellipsoid that represents the viscosity coefficients of the mechanical impedance model. This model determines the dynamic behavior of the master-slave system. The viscosity parameters of the impedance model are changed according to the characteristics of the ellipsoid. As a result, the damping to the direction of a stiff environment increases and that to the maneuvering direction decreases. In addition, the shape and posture of the ellipsoid are automatically adjusted to reflect the operator's intention. With the experimental results of trace work, we show the validity of the proposed method.

A design method is proposed of a master-slave system executing a continuous contact task with high maneuverability. We introduce a variable viscosity-ellipsoid that represents the viscosity coefficients of the mechanical impedance model. This model determines the dynamic behavior of the master-slave system. The viscosity parameters of the impedance model are changed according to the characteristics of the ellipsoid. As a result, the damping to the direction of a stiff environment increases and that to the maneuvering direction decreases. In addition, the shape and posture of the ellipsoid are automatically adjusted to reflect the operator's intention. With the experimental results of trace work, we show the validity of the proposed method.

A design method is proposed of a master-slave system executing a continuous contact task with high maneuverability. We introduce a variable viscosity-ellipsoid that represents the viscosity coefficients of the mechanical impedance model. This model determines the dynamic behavior of the master-slave system. The viscosity parameters of the impedance model are changed according to the characteristics of the ellipsoid. As a result, the damping to the direction of a stiff environment increases and that to the maneuvering direction decreases. In addition, the shape and posture of the ellipsoid are automatically adjusted to reflect the operator's intention. With the experimental results of trace work, we show the validity of the proposed method.

A computational method in conjunction with indentation measurements is presented to determine the yield stress and the tangential modulus of different polymeric materials. A novel approach is developed to select representative points at which finite element calculations are performed. Yield stress and tangential modulus can be obtained by minimizing the deviation between the calculated and the experimental data. Hardness values are also derived using finite element calculations and compared to those obtained from the fitting to the loading curve of depth-sensing experiments. © 1998 Elsevier Science B.V. All rights reserved.

Recently, a structural analysis using new type discrete model was developed by T. Kawai, and it has been applied to limit state analysis of structure and solid. In this paper, non-linear structural analyses by two-dimensional hybrid stress model are presented, where the elements idealized by T. Kawai are applied. Since the elements have a node at mid-point of length of the each boundary side, the analysis is useful for treating non-linear problems including crack and slip. Herein, the hybrid stress model is applied for the bearing capacity of a concrete block, the load carrying capacity of reinforced concrete beam and contact problems of two elastic bodies.

Bakalářská práce se zabývá deformačně-napěťovou analýzou součásti využívané pro regulaci množství přivedeného plynu u plynového kotle. Postupně dojde k seznámení s řešenou problematikou, určení zatížení a následné aplikaci zatížení v programu ANSYS. Na závěr je kapitola věnující se experimentu na samotné součásti., This thesis deals with stress-strain analysis of component, which is used for regulation of gas quantity, which comes into gas boiler. There will be acquaintance with issue, determining load and consecutive application of this load in ANSYS. At the end there is a chapter pursuing of experiment on the component.

Předložená diplomová práce se zabývá napjatostí výdutí mozkových tepen. Je rozdělena do tří částí. První část je věnována rešeršní studii aktuálních článku zabývajících se daným tématem. Další částí je analýza vlivu geometrie mozkové výdutě na napjatost. Analýza byla provedena na čtyřech základních obecných modelech. Byl identifikován nejriskantnější tvar výdutě. Poslední část se zabývá vlivem okolní tkáně na napjatost výdutí mozkových tepen. Byl proveden výpočtový model vlivu okolní tkáně na napjatost mozkových tepen se závěrem, že šedá kůra mozková má příznivý, ovšem nevýznamný vliv na napjatost v mozkových výdutích., This thesis is focused on stress in brain aneurysms. It consists of three parts. First part is aimed for gaining information about the topic from scientific resources. Next part consists of analyses of geometry of cerebral aneurysms on the computed wall stress. Analyses are performed on four basic geometrical models and results are being discussed. The risky areas in each investigated shape have been identified as well as the comparisons of stress between those shapes have been performed and the most dangerous shape among investigated shapes has been determined. Third part investigates the influence of surrounding tissue on the brain aneurysm. Conclusion of this thesis is that brain gray tissue has positive yet negligible effect on the computed wall stress.

Tato práce se zabývá modální analýzou lopatkové řady parní turbíny svázané Z-vazbou. Práce byla řešena pomocí konečnoprvkového systému ANSYS. V práci je využito cyklické symetrie s cílem získat vlastní frekvence celého olopatkovaného disku. Dalším cílem práce bylo zjisti vlastní frekvence volné lopatky a porovnat je s výsledky získanými z experimentu. Pro vytvoření 3D modelu lopatky bylo použito 3D skeneru a CAD systému CATIA., This thesis is about modal analysis of the rotor blades row tied with Z-tie. Thesis was solved by finite element system ANSYS. Cyclic symmetry was used in this thesis with the aim of obtain eigen frequency of bladed disc. The next aim of this thesis was to find eigen frequency of the free rotor blades and to compare it with frequency obtained from experiment. 3D model was created by 3D scanner and CAD system CATIA.

Práce se zabývá simulací dynamického systému s kontaktní úlohou v podobě kontaktu cyklistické duše a pláště při nafukování a zatěžování kola. Teoretická část objasňuje základní pojmy z problematiky dynamických systémů a kontaktních úloh a představuje metody použité pro simulace v praktické části. V praktické části je popsán proces převodu reálného systému ráfek-duše-plášť na výpočetní model v podobě zjištění jeho geometrie a materiálových charakteristik jako spojitého objektu a jeho následné diskretizace, představen program použítý pro simulace (FyDiK 2D) a provedeny vybrané simulace a jejich vyhodnocení., This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.

Táto práca sa zaoberá návrhom dynamického modelu harmonickej prevodovky. Teoretická štúdia tejto práce je zameraná na analýzu princípu harmonickej prevodovky a jej nelineárnych vlastností. V praktickej časti tejto práce je najprv vykonaný analytický výpočet nedeformovaného tvaru Flexspline, na základe ktorého sa vytvorí niekoľko simulácií v programu ANSYS na identifikáciu torzných charakteristík harmonickej prevodovky. Tieto simulačné modely sú ďalej rozšírené o analýzu vplyvu vôle a nepresností na dané torzné charakteristiky. Na základe týchto výsledkov sa následne vytvorí v programe MATLAB/Simulink niekoľko dynamických submodelov reprezentujúcich jednotlivé nelineárne charakteristiky harmonickej prevodovky. Na záver sa vytvorí komplexný dynamický model mechatronického systému popisujúci nelineárne vlastnosti a kinematickú chybu prevodovky. Dynamický model je taktiež experimentálne overený na základe verifikácie tlmenia prevodovky., This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.

Táto práca sa zaoberá návrhom dynamického modelu harmonickej prevodovky. Teoretická štúdia tejto práce je zameraná na analýzu princípu harmonickej prevodovky a jej nelineárnych vlastností. V praktickej časti tejto práce je najprv vykonaný analytický výpočet nedeformovaného tvaru Flexspline, na základe ktorého sa vytvorí niekoľko simulácií v programu ANSYS na identifikáciu torzných charakteristík harmonickej prevodovky. Tieto simulačné modely sú ďalej rozšírené o analýzu vplyvu vôle a nepresností na dané torzné charakteristiky. Na základe týchto výsledkov sa následne vytvorí v programe MATLAB/Simulink niekoľko dynamických submodelov reprezentujúcich jednotlivé nelineárne charakteristiky harmonickej prevodovky. Na záver sa vytvorí komplexný dynamický model mechatronického systému popisujúci nelineárne vlastnosti a kinematickú chybu prevodovky. Dynamický model je taktiež experimentálne overený na základe verifikácie tlmenia prevodovky., This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.

Tato práce se zabývá modální analýzou lopatkové řady parní turbíny svázané Z-vazbou. Práce byla řešena pomocí konečnoprvkového systému ANSYS. V práci je využito cyklické symetrie s cílem získat vlastní frekvence celého olopatkovaného disku. Dalším cílem práce bylo zjisti vlastní frekvence volné lopatky a porovnat je s výsledky získanými z experimentu. Pro vytvoření 3D modelu lopatky bylo použito 3D skeneru a CAD systému CATIA., This thesis is about modal analysis of the rotor blades row tied with Z-tie. Thesis was solved by finite element system ANSYS. Cyclic symmetry was used in this thesis with the aim of obtain eigen frequency of bladed disc. The next aim of this thesis was to find eigen frequency of the free rotor blades and to compare it with frequency obtained from experiment. 3D model was created by 3D scanner and CAD system CATIA.

Předložená diplomová práce se zabývá napjatostí výdutí mozkových tepen. Je rozdělena do tří částí. První část je věnována rešeršní studii aktuálních článku zabývajících se daným tématem. Další částí je analýza vlivu geometrie mozkové výdutě na napjatost. Analýza byla provedena na čtyřech základních obecných modelech. Byl identifikován nejriskantnější tvar výdutě. Poslední část se zabývá vlivem okolní tkáně na napjatost výdutí mozkových tepen. Byl proveden výpočtový model vlivu okolní tkáně na napjatost mozkových tepen se závěrem, že šedá kůra mozková má příznivý, ovšem nevýznamný vliv na napjatost v mozkových výdutích., This thesis is focused on stress in brain aneurysms. It consists of three parts. First part is aimed for gaining information about the topic from scientific resources. Next part consists of analyses of geometry of cerebral aneurysms on the computed wall stress. Analyses are performed on four basic geometrical models and results are being discussed. The risky areas in each investigated shape have been identified as well as the comparisons of stress between those shapes have been performed and the most dangerous shape among investigated shapes has been determined. Third part investigates the influence of surrounding tissue on the brain aneurysm. Conclusion of this thesis is that brain gray tissue has positive yet negligible effect on the computed wall stress.

Táto práca sa zaoberá návrhom dynamického modelu harmonickej prevodovky. Teoretická štúdia tejto práce je zameraná na analýzu princípu harmonickej prevodovky a jej nelineárnych vlastností. V praktickej časti tejto práce je najprv vykonaný analytický výpočet nedeformovaného tvaru Flexspline, na základe ktorého sa vytvorí niekoľko simulácií v programu ANSYS na identifikáciu torzných charakteristík harmonickej prevodovky. Tieto simulačné modely sú ďalej rozšírené o analýzu vplyvu vôle a nepresností na dané torzné charakteristiky. Na základe týchto výsledkov sa následne vytvorí v programe MATLAB/Simulink niekoľko dynamických submodelov reprezentujúcich jednotlivé nelineárne charakteristiky harmonickej prevodovky. Na záver sa vytvorí komplexný dynamický model mechatronického systému popisujúci nelineárne vlastnosti a kinematickú chybu prevodovky. Dynamický model je taktiež experimentálne overený na základe verifikácie tlmenia prevodovky., This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.

Предлагается математическая модель расчета изменяющегося давления при контакте жесткого цилиндрического индентора с вязкоупругой изотропной полосой жестко скрепленной с ортотропным основанием. Решение контактной задачи сводится к интегральному уравнению. Представлена реализация численного решения интегрального уравнения., The mathematical model of calculation of the changing pressure at contact of a rigid cylindrical indenter with a viscoelastic isotropic strip rigidly fastened to an orthotropic basis is offered. The solution of the contact problem is reduced to integral equation. The realization of the numerical solution of the integralequation is presented.

В работе предложена конечно-элементная методика расчета деформирования обделки тоннеля метрополитена,расположенного в сухом и водонасыщенном грунте. Для моделирования заимодействия между элементами деформируемых конструкций и грунтовыми средами используется специальный "контактный" конечный элемент, позволяющий учесть все случаи взаимодействия контактирующих поверхностей. Решен ряд задач деформирования кольца обделки тоннеля метрополитена, расположенного в грунте сложной физической природы., In operation the finite and element method of calculation of deforming of an lining of a tunnel of the subway located in dry and water-saturated soil is offered. For simulation of interaction between elements of deformable constructions and the soil environments the special "contact" terminal element allowing to consider all cases of interaction of the contacting surfaces is used. A row of tasks of deforming of a ring of an lining of a tunnel of the subway located in soil of the difficult physical nature is solved.

In this article, Ritz’s method is used to calculate with unprecedented accuracy the displacements related to a deformable rectangular plate resting on the surface of an elastic quarter-space. To achieve this required three basic steps. The first step involved the study of Green’s function describing the vertical displacements of the surface of an elastic quarter-space due to vertical force applied on its surface. For this case, an explicit formula was obtained by analytically resolving a complicated integral that did not previously have an analytical solution. The second step involved the study of the coupled system of a plate and an elastic quarter-space. This portion focused on determining reactive forces in the contact zone based on Hetenyi’s solution. After determination of the reactive forces, certain features were attributed to the plate’s edges. The final step involved the application of Ritz’s method to determine the deflections of the plate resting on the surface of the quarter-space. Finally, an example calculation and validation of results are given. This is the first semi-analytical solution proposed for this type of contact problem.

Die Bodenverdichtung stellt bei der Herstellung verschiedenster Ingenieurbauwerke eine entscheidende und gleichzeitig kritische Bauphase dar. Denn die Qualität von Auffüllungen im Zuge von Gründungsarbeiten im Hallen- und Industriebau sowie bei der Herstellung von Bodenauswechslungen, Dämmen und Tragschichten im Straßen-, Eisenbahn- und Flughafenbau hängt vom Verfüllmaterial und insbesondere vom Einbauvorgang ab. Dynamische Walzen sind mittlerweile zum bevorzugten Gerät für die oberflächennahe Verdichtung geworden, um zukünftige Schäden an Bauwerken, die mit einem lageweisen hergestellten Erdbauwerk verbunden bzw. darauf gegründet sind, steigende Instandhaltungskosten und eine geringere Lebensdauer des jeweiligen Bauwerks zu vermeiden. Während die Verdichtungswirkung einer statischen Walze im Wesentlichen vom Eigengewicht der Maschine und gegebenenfalls von der Bandagengeometrie und -oberfläche bestimmt wird, lässt sich bei dynamischen Walzen die Effizienz der Untergrundverdichtung durch die dynamische Anregung der Bandage erhöhen. In Abhängigkeit von der Art der Bandagenanregung lassen sich grundsätzlich zwei Typen von dynamischen Walzen unterscheiden, nämlich Vibrations- und Oszillationswalzen. In einer Vibrationsbandage erzeugt eine Unwuchtmasse, die in der Bandagenachse angeordnet und mit einer festgelegten Frequenz um die Achse rotiert, eine schnell wechselnde Aufwärts-Abwärts-Bewegung. Der Untergrund wird durch die von der Bandage ausgeübten, vorwiegend vertikal gerichteten Schläge verdichtet. In einer Oszillationsbandage, die Gegenstand der vorliegenden Arbeit ist, sind zwei Unwuchtmassen mit derselben Größe und Exzentrizität punktsymmetrisch zur Bandagenachse angeordnet, die synchron in die gleiche Richtung drehen. Die daraus resultierende wechselnde hochfrequente Vorwärts-Rückwärts-Rotation der Bandage (rotatorische Schwingung) wird der Fahrbewegung (rollende Bandage unter der statischen Achslast) überlagert. Infolge Reibung in der Kontaktfläche zwischen Ba, Soil compaction is a fundamental and critical construction phase of a wide variety of engineering structures, since the quality of fills in foundation work of hall and industrial facilities, soil replacements, dam and base layers in road, railway and airport construction depends on the built-in material and in particular on the realization of earthwork. Dynamic roller compaction has become the common method for proper near-surface compaction to prevent future damage of constructions connected to layered earth structures, failure of long-term pavement performances and increasing maintenance costs. While a static roller uses only its weight to compact filled layers, a dynamic roller enhances the efficiency of subsurface compaction through dynamic excitation of the drum. Depending on the drum excitation, two basic types of dynamic rollers do exist, i.e. vibratory rollers and oscillation rollers. In a vibrating drum a single unbalance mass, which is attached concentrically to the drum axis, generates a rapidly alternating upward-downward motion of the drum. The subgrade is compacted by the dynamic pressure applied by the drum. The drum of an oscillation roller, as considered in the present thesis, is equipped with two offset eccentric masses, which rotate synchronously in the same direction. The resulting alternating high-frequency forward-backward motion of the drum (oscillatory drum motion) is superposed with the translational roller motion (moving drum under the static axle load). Due to the frictional contact between drum and subsoil mainly dynamic shear forces are transmitted to the soil, which in turn increase the subgrade density, also known as shear force compaction. The lack of real-time compaction information may lead to both under- and overcompaction and, moreover, to an increased wear of the drum of oscillation rollers. Thus, instant compaction control is of particular importance. A high-leveled quality management requires continuous control of the soil comp, Dipl.-Ing. Ivan Paulmichl, Abweichender Titel laut Übersetzung der Verfasserin/des Verfassers, Dissertation Universität Innsbruck 2019

Práce se zabývá simulací dynamického systému s kontaktní úlohou v podobě kontaktu cyklistické duše a pláště při nafukování a zatěžování kola. Teoretická část objasňuje základní pojmy z problematiky dynamických systémů a kontaktních úloh a představuje metody použité pro simulace v praktické části. V praktické části je popsán proces převodu reálného systému ráfek-duše-plášť na výpočetní model v podobě zjištění jeho geometrie a materiálových charakteristik jako spojitého objektu a jeho následné diskretizace, představen program použítý pro simulace (FyDiK 2D) a provedeny vybrané simulace a jejich vyhodnocení., This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.

Práce se zabývá simulací dynamického systému s kontaktní úlohou v podobě kontaktu cyklistické duše a pláště při nafukování a zatěžování kola. Teoretická část objasňuje základní pojmy z problematiky dynamických systémů a kontaktních úloh a představuje metody použité pro simulace v praktické části. V praktické části je popsán proces převodu reálného systému ráfek-duše-plášť na výpočetní model v podobě zjištění jeho geometrie a materiálových charakteristik jako spojitého objektu a jeho následné diskretizace, představen program použítý pro simulace (FyDiK 2D) a provedeny vybrané simulace a jejich vyhodnocení., This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.

Bakalářská práce se zabývá deformačně-napěťovou analýzou součásti využívané pro regulaci množství přivedeného plynu u plynového kotle. Postupně dojde k seznámení s řešenou problematikou, určení zatížení a následné aplikaci zatížení v programu ANSYS. Na závěr je kapitola věnující se experimentu na samotné součásti., This thesis deals with stress-strain analysis of component, which is used for regulation of gas quantity, which comes into gas boiler. There will be acquaintance with issue, determining load and consecutive application of this load in ANSYS. At the end there is a chapter pursuing of experiment on the component.

Bakalářská práce se zabývá deformačně-napěťovou analýzou součásti využívané pro regulaci množství přivedeného plynu u plynového kotle. Postupně dojde k seznámení s řešenou problematikou, určení zatížení a následné aplikaci zatížení v programu ANSYS. Na závěr je kapitola věnující se experimentu na samotné součásti., This thesis deals with stress-strain analysis of component, which is used for regulation of gas quantity, which comes into gas boiler. There will be acquaintance with issue, determining load and consecutive application of this load in ANSYS. At the end there is a chapter pursuing of experiment on the component.

Táto práca sa zaoberá návrhom dynamického modelu harmonickej prevodovky. Teoretická štúdia tejto práce je zameraná na analýzu princípu harmonickej prevodovky a jej nelineárnych vlastností. V praktickej časti tejto práce je najprv vykonaný analytický výpočet nedeformovaného tvaru Flexspline, na základe ktorého sa vytvorí niekoľko simulácií v programu ANSYS na identifikáciu torzných charakteristík harmonickej prevodovky. Tieto simulačné modely sú ďalej rozšírené o analýzu vplyvu vôle a nepresností na dané torzné charakteristiky. Na základe týchto výsledkov sa následne vytvorí v programe MATLAB/Simulink niekoľko dynamických submodelov reprezentujúcich jednotlivé nelineárne charakteristiky harmonickej prevodovky. Na záver sa vytvorí komplexný dynamický model mechatronického systému popisujúci nelineárne vlastnosti a kinematickú chybu prevodovky. Dynamický model je taktiež experimentálne overený na základe verifikácie tlmenia prevodovky., This thesis deals with the design of a dynamic model of a harmonic drive. It includes a theoretical study aimed at the analysis of the harmonic drive gearing principle and its nonlinear properties. The first part of the practical section deals with the analytical calculation of the nondeformed geometry of the Flexspline. Based on these results, several simulations in ANSYS are created to identify torsional characteristics of a harmonic drive. These simulation models are further enhanced by the analysis of clearance, backlash and inaccuracies and their impact on torsional properties. By using MATLAB /Simulink, several dynamic submodels are created representing the individual characteristics of nonlinearities in harmonic drives. Furthermore, a comprehensive dynamic model is created of the mechatronic system which is describing all nonlinearities and kinematic error of the transmission. The dynamic model is also experimentally verified based on its damping properties.

Tato práce se zabývá modální analýzou lopatkové řady parní turbíny svázané Z-vazbou. Práce byla řešena pomocí konečnoprvkového systému ANSYS. V práci je využito cyklické symetrie s cílem získat vlastní frekvence celého olopatkovaného disku. Dalším cílem práce bylo zjisti vlastní frekvence volné lopatky a porovnat je s výsledky získanými z experimentu. Pro vytvoření 3D modelu lopatky bylo použito 3D skeneru a CAD systému CATIA., This thesis is about modal analysis of the rotor blades row tied with Z-tie. Thesis was solved by finite element system ANSYS. Cyclic symmetry was used in this thesis with the aim of obtain eigen frequency of bladed disc. The next aim of this thesis was to find eigen frequency of the free rotor blades and to compare it with frequency obtained from experiment. 3D model was created by 3D scanner and CAD system CATIA.

Práce se zabývá simulací dynamického systému s kontaktní úlohou v podobě kontaktu cyklistické duše a pláště při nafukování a zatěžování kola. Teoretická část objasňuje základní pojmy z problematiky dynamických systémů a kontaktních úloh a představuje metody použité pro simulace v praktické části. V praktické části je popsán proces převodu reálného systému ráfek-duše-plášť na výpočetní model v podobě zjištění jeho geometrie a materiálových charakteristik jako spojitého objektu a jeho následné diskretizace, představen program použítý pro simulace (FyDiK 2D) a provedeny vybrané simulace a jejich vyhodnocení., This work deals with the simulation of a dynamical system with a contact problem represented by the contact of a bicycle tube with a tire during inflation and loading of a bicycle wheel. In the first part the work defines the basics of dynamical systems a contact problems and introduces the methods used for following simulations. The practical part of the work desribes the process of converting a real system of rim-tube-tire objects to a computional model by determining its geometry and material characteristics as a continuous object and its subsequent discretization, introduces the program used for the subsequent simulations (FyDiK 2D) and shows the results of said simulations.