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Implementation of control software of device for measuring residual stresses by drilling method
Švehla, Lukáš ; Houfek, Lubomír (referee) ; Krejčí, Petr (advisor)
The diplom thesis deals with modernization of older drill out machine MTS3000 for measurement of residual stress. To make the device work it is necessary to keep running computer control card and necessary software. Because a producer does not provide any upgrade, it was decided to put the device into operation by creating new software. At first an analysis of drilling method and function of device MTS3000 - Restan was made. Next step was to disassemble and analyze the station of the drilling device. Then the station was put into operation and modified for control via USB device NI USB 6009. Finally a computer program in LabVIEW environment was created to automate the measurement process. Program has two main tasks: one is to control the drilling cycle of the machine. Another one is to acquire data from measuring amplifier station.
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Application of DIC method in residual stress measurement using hole drilling method
Kováříková, Sabina ; Kubík, Petr (referee) ; Návrat, Tomáš (advisor)
This thesis deals with measurement of residual stress by hole drilling method. This method is based on drilling a hole and measurement of deformation in the area around this hole. Measured deformations are then converted to residual stresses by using calibration coefficients. The deformation around the drilled hole is measured by optical non contact method called digital image correlation (DIC). First part of the thesis is focused on current state of research. The thesis contains evaluation of residual stresses by using different methods and evaluation of used methods.
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Issue of Internal Tension in Materials during Machining of Thin-walled Components
Osička, Petr ; Chladil, Josef (referee) ; Sedlák, Josef (advisor)
This master thesis focuses on analysing the origins of residual stress in material caused by face milling. Representatives of three groups of aluminum alloys (5000, 6000, 7000) are compared by measurements. For measuring of the residual stress in aluminum alloys, the hole-drilling method was used by applying tensometric rosettes. In order to determine the influence of the used milling cutters', flatness of the machined surface was analyzed by comparative method. The thesis concludes with a discussion and an overall evaluation of the results.
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Design and realization of experimental equipment for determination of residual stress of bent samples
Novotný, Lukáš ; Návrat, Tomáš (referee) ; Krejčí, Petr (advisor)
The master thesis is focused to design and realization of experimental equipment for researching of residual stress determination for specimen with non-uniform distribution stress along the depth. Literature search study of problematic was performed and it was used for elaboration of chapters about origin of residual stress, their classification and chapters about methods, which are used for measuring of residual stress and their determination. The following part explains the design of experimental equipment and stress-strain analysis of selected parts of this equipment. Then the final design of equipment is presented, including complete production drawings, and it’s explained final assembling of experimental equipment. Final chapter is devoted to examinable loading of specimen.
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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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Determination of residual stresses from strain field around drilled hole
Horák, Richard ; Návrat, Tomáš (referee) ; Halabuk, Dávid (advisor)
The master’s thesis focuses on determining homogeneous residual stresses using the hole-drilling method. The optical method of digital image correlation (DIC) is used for measuring released strains. In order to evaluate residual stresses using the entire strain field, it is necessary to know the functional dependencies of calibration constants on this field. Therefore, a significant part of the master’s thesis includes finding these dependencies in relation to the dimensions of the drilled hole and coordinates of the measured points. Another part of the thesis deals with the evaluation of homogeneous residual stresses based on provided experimental data obtained from the measurement of uniaxially loaded steel flat bar with a through-hole. At the end of the thesis, a sensitivity analysis is performed, which examines the influence of input variables in the calculation algorithm in relation to computed residual stresses.
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Implementation of control software of device for measuring residual stresses by drilling method
Švehla, Lukáš ; Houfek, Lubomír (referee) ; Krejčí, Petr (advisor)
The diplom thesis deals with modernization of older drill out machine MTS3000 for measurement of residual stress. To make the device work it is necessary to keep running computer control card and necessary software. Because a producer does not provide any upgrade, it was decided to put the device into operation by creating new software. At first an analysis of drilling method and function of device MTS3000 - Restan was made. Next step was to disassemble and analyze the station of the drilling device. Then the station was put into operation and modified for control via USB device NI USB 6009. Finally a computer program in LabVIEW environment was created to automate the measurement process. Program has two main tasks: one is to control the drilling cycle of the machine. Another one is to acquire data from measuring amplifier station.
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Application of DIC method in residual stress measurement using hole drilling method
Kováříková, Sabina ; Kubík, Petr (referee) ; Návrat, Tomáš (advisor)
This thesis deals with measurement of residual stress by hole drilling method. This method is based on drilling a hole and measurement of deformation in the area around this hole. Measured deformations are then converted to residual stresses by using calibration coefficients. The deformation around the drilled hole is measured by optical non contact method called digital image correlation (DIC). First part of the thesis is focused on current state of research. The thesis contains evaluation of residual stresses by using different methods and evaluation of used methods.
|
|
|
Design and realization of experimental equipment for determination of residual stress of bent samples
Novotný, Lukáš ; Návrat, Tomáš (referee) ; Krejčí, Petr (advisor)
The master thesis is focused to design and realization of experimental equipment for researching of residual stress determination for specimen with non-uniform distribution stress along the depth. Literature search study of problematic was performed and it was used for elaboration of chapters about origin of residual stress, their classification and chapters about methods, which are used for measuring of residual stress and their determination. The following part explains the design of experimental equipment and stress-strain analysis of selected parts of this equipment. Then the final design of equipment is presented, including complete production drawings, and it’s explained final assembling of experimental equipment. Final chapter is devoted to examinable loading of specimen.
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Issue of Internal Tension in Materials during Machining of Thin-walled Components
Osička, Petr ; Chladil, Josef (referee) ; Sedlák, Josef (advisor)
This master thesis focuses on analysing the origins of residual stress in material caused by face milling. Representatives of three groups of aluminum alloys (5000, 6000, 7000) are compared by measurements. For measuring of the residual stress in aluminum alloys, the hole-drilling method was used by applying tensometric rosettes. In order to determine the influence of the used milling cutters', flatness of the machined surface was analyzed by comparative method. The thesis concludes with a discussion and an overall evaluation of the results.
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