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Comprehensive structural analysis of compressor wheel using FEM
Chromek, Lukáš ; Nehybka, Jindřich (referee) ; Civín, Adam (advisor)
This thesis explores the utilization of FEM software ANSYS in the analysis of the real blade wheel of a radial compressor used in small turbine aviation motors. This apparatus is made by První brněnská strojírna a.s., and its detached site in Velká Bíteš where it has the aviation engineering division. The aim of this thesis is a comprehensive blade wheel analysis composed of several steps. These steps include static and elasto-plastic strength analysis, which describes stress distribution and its assessment from the perspective of boundary conditions of elasticity during the use of the Hooke and the non-linear model of the material. Another step is dynamic analysis; in this case modal analysis, which describes the frequencies and its waveforms. The last part of the thesis contains thermal analysis while considering stationary and non-stationary thermal field. The analysis is then transformed into thermal-stress coupled analysis, which describes stress distribution resulting from thermal expansion of the material. The thesis follows the process of calculation simulations that are used during the design of a real impeller, thus before the creation of a prototype that undergoes real experiments.
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Comprehesive Theoeretical Analysis of Ring-Core Method for Residual Stress Determination
Civín, Adam ; Holý, Stanislav (referee) ; Plánička, František (referee) ; Frydrýšek,, Karel (referee) ; Vlk, Miloš (advisor)
Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.
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Assesment of residual stress with drilling hole method using FEM
Civín, Adam ; Vlk, Miloš (referee) ; Hlavoň, Pavel (advisor)
Residual state of stress in structural materials affect positively or negatively behaviour of component parts. The goal of this scope is not to deal with possible process of creating residual stresses neither about elimination of residual stress, but is focused how to determine magnitude of residual stress by hole-drilling method. We need to know magnitude and direction (angular orientation) of principal stresses to determine how residual state of stress affects behaviour of specimen. The most widely used modern technique for measuring residual stresses is hole-drilling strain-gage method. Hole-drilling method is in scope of this paper and is restricted only for measuring uniform residual stresses of steel specimens with finite dimensions. Structural, linear, elastic and isotropic material model is used with material properties =0,3 and E=2,1[10]^5 MPa. For correct application of this method we need to determine calibration coefficients “a“ and “b“ first. These coefficients are used to determine magnitude and direction of residual stresses in specific depth and diameter of drilled hole for materials with finite dimensions. Geometry and shape of model is simply represented by block with planar faces. Note that numerical determination of calibration coefficients is useful only for one type of strain gauge rosette RY 61 S. Main goals of this thesis are motivation and request to clearly report effectiveness, accuracy and applicability of calibration coefficients in relation to thickness of specimen, dimensions of drilled hole, condition of “through” or “blind” hole and number of drilled increments. High quality and accuracy of created numerical model is necessary too. Numerical simulation of residual stresses by MKP needs to be done to obtain requested results. All results are presented by 3D, 2D graphs and tables and compared with analytical results or results from other authors. Although is this publication focused on numerical modeling using FEM, hole-drilling method has many significant restrictions. The most substantial of them is influence of eccentricity of drilled hole, creation of stress concentration near drilled area and subsequent plastification, influence of geometrical inaccuracy of hole, etc. All these aspects have significant influence of determining calibration coefficients and can not be included into numerical simulation. These problems are closely discussed in background research. All obtained results should be helpful for practical use of calculated calibration coefficients to determine uniform residual stresses of specimens with various thickness and drilled hole. All these results are also applicable only for one type of strain gauge rosette, which is RY 61 S.
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Comprehesive Theoeretical Analysis of Ring-Core Method for Residual Stress Determination
Civín, Adam ; Vlk, Miloš (advisor)
Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.
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|
|
Comprehesive Theoeretical Analysis of Ring-Core Method for Residual Stress Determination
Civín, Adam ; Holý, Stanislav (referee) ; Plánička, František (referee) ; Frydrýšek,, Karel (referee) ; Vlk, Miloš (advisor)
Comprehensive analysis of the ringcore method used for the determination of the residual stresses in mechanical components is presented in this thesis. Principles, advantages, disadvantages and applicability of this semidestructive experimental method are discussed too. At the same time the ringcore method is compared with the hole drilling method, which is used more frequently. All aspects of the ringcore method are analyzed by the finite element method. FE simulations, performed on the universal numerical model, verified principles of the integral method and the incremental strain method. FE simulations also provided basic information for the uncertainty analysis, which significantly affects the accuracy of the residual stress measurement. The main goal, which the present work deals with, is to create a global overview of all ringcore methods´ aspects elaborated in a clear and complex form.
|
|
|
Comprehensive structural analysis of compressor wheel using FEM
Chromek, Lukáš ; Nehybka, Jindřich (referee) ; Civín, Adam (advisor)
This thesis explores the utilization of FEM software ANSYS in the analysis of the real blade wheel of a radial compressor used in small turbine aviation motors. This apparatus is made by První brněnská strojírna a.s., and its detached site in Velká Bíteš where it has the aviation engineering division. The aim of this thesis is a comprehensive blade wheel analysis composed of several steps. These steps include static and elasto-plastic strength analysis, which describes stress distribution and its assessment from the perspective of boundary conditions of elasticity during the use of the Hooke and the non-linear model of the material. Another step is dynamic analysis; in this case modal analysis, which describes the frequencies and its waveforms. The last part of the thesis contains thermal analysis while considering stationary and non-stationary thermal field. The analysis is then transformed into thermal-stress coupled analysis, which describes stress distribution resulting from thermal expansion of the material. The thesis follows the process of calculation simulations that are used during the design of a real impeller, thus before the creation of a prototype that undergoes real experiments.
|
|
|
Assesment of residual stress with drilling hole method using FEM
Civín, Adam ; Vlk, Miloš (referee) ; Hlavoň, Pavel (advisor)
Residual state of stress in structural materials affect positively or negatively behaviour of component parts. The goal of this scope is not to deal with possible process of creating residual stresses neither about elimination of residual stress, but is focused how to determine magnitude of residual stress by hole-drilling method. We need to know magnitude and direction (angular orientation) of principal stresses to determine how residual state of stress affects behaviour of specimen. The most widely used modern technique for measuring residual stresses is hole-drilling strain-gage method. Hole-drilling method is in scope of this paper and is restricted only for measuring uniform residual stresses of steel specimens with finite dimensions. Structural, linear, elastic and isotropic material model is used with material properties =0,3 and E=2,1[10]^5 MPa. For correct application of this method we need to determine calibration coefficients “a“ and “b“ first. These coefficients are used to determine magnitude and direction of residual stresses in specific depth and diameter of drilled hole for materials with finite dimensions. Geometry and shape of model is simply represented by block with planar faces. Note that numerical determination of calibration coefficients is useful only for one type of strain gauge rosette RY 61 S. Main goals of this thesis are motivation and request to clearly report effectiveness, accuracy and applicability of calibration coefficients in relation to thickness of specimen, dimensions of drilled hole, condition of “through” or “blind” hole and number of drilled increments. High quality and accuracy of created numerical model is necessary too. Numerical simulation of residual stresses by MKP needs to be done to obtain requested results. All results are presented by 3D, 2D graphs and tables and compared with analytical results or results from other authors. Although is this publication focused on numerical modeling using FEM, hole-drilling method has many significant restrictions. The most substantial of them is influence of eccentricity of drilled hole, creation of stress concentration near drilled area and subsequent plastification, influence of geometrical inaccuracy of hole, etc. All these aspects have significant influence of determining calibration coefficients and can not be included into numerical simulation. These problems are closely discussed in background research. All obtained results should be helpful for practical use of calculated calibration coefficients to determine uniform residual stresses of specimens with various thickness and drilled hole. All these results are also applicable only for one type of strain gauge rosette, which is RY 61 S.
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