|
|
Comparative analysis of notched machine parts using photoelasticity and FEM
Bittner, Jiří ; Náhlík, Luboš (referee) ; Vaverka, Michal (advisor)
The diploma thesis deals with comparative analysis of stress and strain of notched machine parts using photoelasticity and finite element method (FEM). Experimental and numerical comparative analyses were performed on three models: hook, J shaped bracket and 3-point bending beam with notch. Equivalent stresses, principal stresses and its directions were analyzed. The emphasis is given on photoelasticity, the theory and principles of photoelasticity are described in more detail. FEM analysis was performed using software ANSYS 11. The work presented includes the preparation of polariscope in the laboratory of Institute of machine and industrial design in order to use it in tutorials focused on experimental stress analysis using photoelasticity.
|
|
| |
|
|
Sensitivity Analysis of the Material Parameters Obtained from the Measurements
Fuis, Vladimír
The paper deals with sensitivity analysis of the material parameters of the ceramic material on the dispersion of the measured data from the sensors. Material parameters of ceramic material are calculated from a set of destruction tests of ceramic heads of total hip joint replacements. The standard way of calculation of the ceramic material parameters consists in carrying out a set of 3 (or 4) point bending tests of specimens which were cut out from parts of the ceramic material to be analysed. In case of ceramic heads of the prosthesis, it is not possible to cut out specimens of required dimensions because the heads are too small. On that score, a special testing jig was made, in which 40 heads were destructed. From the measured values of circumferential strains of the head’s external spherical surface under destruction (by the sensors – strain gauges), the state of stress in the head under destruction was established using the finite elements method. From the obtained values the material parameters of the ceramic material were calculated using Weibull’s weakest-link theory. The calculated material parameters (Weibull modulus m and normalized volume strength σo, the last material parameter – stress σu is assumed to be equal 0 and corresponds to the conservative approach) has the dispersion and the influence of this dispersion (in our case the dispersion ± 5 % is assumed) is analysed in detail.
|
|
| |
|
|
Comparative analysis of notched machine parts using photoelasticity and FEM
Bittner, Jiří ; Náhlík, Luboš (referee) ; Vaverka, Michal (advisor)
The diploma thesis deals with comparative analysis of stress and strain of notched machine parts using photoelasticity and finite element method (FEM). Experimental and numerical comparative analyses were performed on three models: hook, J shaped bracket and 3-point bending beam with notch. Equivalent stresses, principal stresses and its directions were analyzed. The emphasis is given on photoelasticity, the theory and principles of photoelasticity are described in more detail. FEM analysis was performed using software ANSYS 11. The work presented includes the preparation of polariscope in the laboratory of Institute of machine and industrial design in order to use it in tutorials focused on experimental stress analysis using photoelasticity.
|
guest ::
