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Static and dynamic analysis of Prestressed bridge structure
Hokeš, Filip ; Nečas, Radim (referee) ; Kala, Jiří (advisor)
The main objective of the thesis is to perform static and dynamic analysis of prestressed concrete bridge structures in computational system ANSYS. For the analysis was chosen footbridge over the river Svratka in Brno. In relation to this topic are solved various types of modeling prestress at a finite element level. Before analyzing the footbridge is analyzed in detail the static system and the corresponding final geometry of the structure. Knowledge of the functioning of the static system is used to build the computational model of the structure, on which is subsequently performed static and dynamic analysis.
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3D models of stress tensor
Stieber, Petr ; Pokorný, Přemysl (referee) ; Malášek, Jiří (advisor)
The aim of this bachelor´s thesis is to create 3D models of stress tensor. Mohr´s circles serve as a base for identification of size and direction of stress component. These are then used for the 3D modelling in software Rhinoceros. Final models in the form of colored areas show general, normal and shear stress for the individual states of stress.
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Static analysis of flexibly supported on structures
Šnajdárková, Jana ; Brdečko, Luděk (referee) ; Vlk, Zbyněk (advisor)
This work focuses on comparing the static analysis on the various types of models. It is calculated as manual calculations and in software RFEM. Without use of the software are created simplified beam model on fixed and flexible supports and to them are calculated support reactions, shear forces and bending moments. One part focuses on the calculation of the reduction of bending moments, to achieve more accurate results. In the program are created models of rod and models of space, which are composed of surfaces. There is also created a model of the split rod to form a reduction of the bending moments over the supports. The last model is a beam with two separate chambers, which are fixed to the plate and defined as ribs which cooperates with the plate. Internal forces on all models is then compared.
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Use of finite element method for stress evaluation in layers for optical applications
Tesařová, Anežka ; Ohlídal, Miloslav (referee) ; Burša, Jiří (advisor)
This thesis is concerned with the mechanical stress generated in thin layers applied on a substrate. The application takes place at high temperatures and due to different coefficients of thermal expansion of materials, the sample is deformed, and thereby the stress is generated. The first part of the thesis includes the derivation of the Stoney formula for uniaxial and biaxial stress in a layer. Besides, analytical calculations of the normal stress in the layer for the simplified link model, and shear stress on the layer interface were evaluated. The main part of the work consists of solving the problem using FEM modeling. Because the actual temperature behavior during the application was not known, a fictitious temperature load was used as an input. For the samples, the coefficients of thermal expansion of the layer were then searched so that the thermal load resulting deflection corresponds to the experimental data. Three types of models were created, namely the link body model, the axisymmetric model, and the solid model. The axisymmetric model was used for the calculation of samples forming circular isolines during deformation and a volume model for samples forming elliptical isolines. The result of the FEM calculations was the normal stress in the applied layers, for which corresponding relationships were created using regression analysis.
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Viscoelastic properties of ferrofluid - Study of normal stresses differences
Šustková, Hana
Since 1960, a liquid becoming strongly magnetized in the presence of a magnetic field, called ferrofluid, is known. This colloidal liquid made of ferro- or ferrimagnetic nanoparticles, with diameter in range 10-20 nm, suspended in a carrier fluid. This work focuses on the study of the viscoelastic properties of a selected ferrofluid - the steady-state and dynamic properties of the fluid with comparison to a standard fluid (basis fluid, etc.) and a MR fluid. Rheological measurements are carried out using a commercial rheometer. A magnetic cell for this rheometer is designed and built. In this magnetic cell the experiments are realized, the whole system is calibrated and the experiments performed. The ferrofluid APG513a, MR-fluid and reference fluid were used. Study of normal stresses differences (N1,N2) in liquids is carried out. According to derived theoretical model, the course of N1 and N2 should be strongly dependent on the field - this was studied directly by measuring of the normal forces or indirectly applying the Laun's rule. A good accordance of theory and experiment was found and an anisotropic behaviour of ferrofluid was studied. The shear-thinning ability of the ferrofluid in normal direction for shear experiment is found to be much stronger than in shear direction. In dynamical mode, the...
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Use of finite element method for stress evaluation in layers for optical applications
Tesařová, Anežka ; Ohlídal, Miloslav (referee) ; Burša, Jiří (advisor)
This thesis is concerned with the mechanical stress generated in thin layers applied on a substrate. The application takes place at high temperatures and due to different coefficients of thermal expansion of materials, the sample is deformed, and thereby the stress is generated. The first part of the thesis includes the derivation of the Stoney formula for uniaxial and biaxial stress in a layer. Besides, analytical calculations of the normal stress in the layer for the simplified link model, and shear stress on the layer interface were evaluated. The main part of the work consists of solving the problem using FEM modeling. Because the actual temperature behavior during the application was not known, a fictitious temperature load was used as an input. For the samples, the coefficients of thermal expansion of the layer were then searched so that the thermal load resulting deflection corresponds to the experimental data. Three types of models were created, namely the link body model, the axisymmetric model, and the solid model. The axisymmetric model was used for the calculation of samples forming circular isolines during deformation and a volume model for samples forming elliptical isolines. The result of the FEM calculations was the normal stress in the applied layers, for which corresponding relationships were created using regression analysis.
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Viscoelastic properties of ferrofluid - Study of normal stresses differences
Šustková, Hana
Since 1960, a liquid becoming strongly magnetized in the presence of a magnetic field, called ferrofluid, is known. This colloidal liquid made of ferro- or ferrimagnetic nanoparticles, with diameter in range 10-20 nm, suspended in a carrier fluid. This work focuses on the study of the viscoelastic properties of a selected ferrofluid - the steady-state and dynamic properties of the fluid with comparison to a standard fluid (basis fluid, etc.) and a MR fluid. Rheological measurements are carried out using a commercial rheometer. A magnetic cell for this rheometer is designed and built. In this magnetic cell the experiments are realized, the whole system is calibrated and the experiments performed. The ferrofluid APG513a, MR-fluid and reference fluid were used. Study of normal stresses differences (N1,N2) in liquids is carried out. According to derived theoretical model, the course of N1 and N2 should be strongly dependent on the field - this was studied directly by measuring of the normal forces or indirectly applying the Laun's rule. A good accordance of theory and experiment was found and an anisotropic behaviour of ferrofluid was studied. The shear-thinning ability of the ferrofluid in normal direction for shear experiment is found to be much stronger than in shear direction. In dynamical mode, the...
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Static and dynamic analysis of Prestressed bridge structure
Hokeš, Filip ; Nečas, Radim (referee) ; Kala, Jiří (advisor)
The main objective of the thesis is to perform static and dynamic analysis of prestressed concrete bridge structures in computational system ANSYS. For the analysis was chosen footbridge over the river Svratka in Brno. In relation to this topic are solved various types of modeling prestress at a finite element level. Before analyzing the footbridge is analyzed in detail the static system and the corresponding final geometry of the structure. Knowledge of the functioning of the static system is used to build the computational model of the structure, on which is subsequently performed static and dynamic analysis.
|
|
|
3D models of stress tensor
Stieber, Petr ; Pokorný, Přemysl (referee) ; Malášek, Jiří (advisor)
The aim of this bachelor´s thesis is to create 3D models of stress tensor. Mohr´s circles serve as a base for identification of size and direction of stress component. These are then used for the 3D modelling in software Rhinoceros. Final models in the form of colored areas show general, normal and shear stress for the individual states of stress.
|
|
|
Static analysis of flexibly supported on structures
Šnajdárková, Jana ; Brdečko, Luděk (referee) ; Vlk, Zbyněk (advisor)
This work focuses on comparing the static analysis on the various types of models. It is calculated as manual calculations and in software RFEM. Without use of the software are created simplified beam model on fixed and flexible supports and to them are calculated support reactions, shear forces and bending moments. One part focuses on the calculation of the reduction of bending moments, to achieve more accurate results. In the program are created models of rod and models of space, which are composed of surfaces. There is also created a model of the split rod to form a reduction of the bending moments over the supports. The last model is a beam with two separate chambers, which are fixed to the plate and defined as ribs which cooperates with the plate. Internal forces on all models is then compared.
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