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Computer simulations of biaxial tension tests of soft biological tissues
Slažanský, Martin ; Návrat, Tomáš (referee) ; Polzer, Stanislav (advisor)
Within the master thesis a computational model of biaxial tension test of soft biological tissues was developed. The tested specimen can be attached using clamps or hooks. The number and the size of clamps and hooks have a significant impact on the distribution of stress and strain in the centre of the specimen, where deformation is measured. Using the developed computational model, a sensitivity analysis of number and size of clamps and hooks and a sensitivity analysis of placement of clamps was elaborated. The number and size of clamps and hooks were optimized in such a way that the material’s parameters obtained by the tension test correspond to the utmost to the actual parameters of the material. By analyzing the placement of clamps, the influence of selected deviations on the outcome of the tension test was determined. Finally, a plan of the next course of action has been proposed.
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Influence of strain rate on stress-strain dependencies of aortic tissues
Slažanský, Martin ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
The thesis deals with the influence of strain rate on stress-strain dependencies of aortic tissues to estimate the error of hyperelastic models, which are neglecting the viscoelastic effects that are typical for soft biological tissues. It was found by the experiment and the subsequent evaluation that in the range of the strain rate from 0,167 to 5,000 mm/s the influence of strain rate on stress-strain dependencies is negligible. The deviation by transition from experimental data to a constitutive model was significantly larger than the deviation between the data sets varying at different strain rates, which means that the use of stress-strain curves varying at different strain rates in given range of the strain rate has no effect on the resulting model. The best of analysis models that were examined in this thesis appears to be the Yeoh hyperelastic model using the FEM.
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Computer simulations of biaxial tension tests of soft biological tissues
Slažanský, Martin ; Návrat, Tomáš (referee) ; Polzer, Stanislav (advisor)
Within the master thesis a computational model of biaxial tension test of soft biological tissues was developed. The tested specimen can be attached using clamps or hooks. The number and the size of clamps and hooks have a significant impact on the distribution of stress and strain in the centre of the specimen, where deformation is measured. Using the developed computational model, a sensitivity analysis of number and size of clamps and hooks and a sensitivity analysis of placement of clamps was elaborated. The number and size of clamps and hooks were optimized in such a way that the material’s parameters obtained by the tension test correspond to the utmost to the actual parameters of the material. By analyzing the placement of clamps, the influence of selected deviations on the outcome of the tension test was determined. Finally, a plan of the next course of action has been proposed.
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Influence of strain rate on stress-strain dependencies of aortic tissues
Slažanský, Martin ; Fuis, Vladimír (referee) ; Burša, Jiří (advisor)
The thesis deals with the influence of strain rate on stress-strain dependencies of aortic tissues to estimate the error of hyperelastic models, which are neglecting the viscoelastic effects that are typical for soft biological tissues. It was found by the experiment and the subsequent evaluation that in the range of the strain rate from 0,167 to 5,000 mm/s the influence of strain rate on stress-strain dependencies is negligible. The deviation by transition from experimental data to a constitutive model was significantly larger than the deviation between the data sets varying at different strain rates, which means that the use of stress-strain curves varying at different strain rates in given range of the strain rate has no effect on the resulting model. The best of analysis models that were examined in this thesis appears to be the Yeoh hyperelastic model using the FEM.
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