National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Computational Modeling of Nanoindentation
Kovář, Jaroslav ; Čech,, Jaroslav (referee) ; Dlouhý, Ivo (referee) ; Fuis, Vladimír (advisor)
Doctoral thesis is aimed on the computation modelling of a nanoindentation test. The informa-tional research of nanoindentation test and analytical models, which were used for derivation of the formulas for evaluation of measured data, is done in the introduction. Analytical models were derived with few simplifying assumptions, whose influence was analyzed in the computa-tional part of the thesis. This part is aimed on the computational modelling of nanoindentation test with the use of finite element method, especially the nanoindentation test of fused silica, steel and thin layers deposited on substrate. These models were used for refinement of calculations by the influence of radial displacements under the tip of indenter and correction coefficient for the indenter shape. In the next part, the influence of the indenter bluntness and tilt on its shape function was analyzed. The last part of the thesis dealing with thin layers was aimed on the verification of one tenth rule of thumb for determination of reduced modulus and hardness with the blunted and ideal Berkovich indenter.
Computational modelling of the nanoindentation with Berkovich indenter
Fiala, Lukáš ; Fuis, Vladimír (referee) ; Kovář, Jaroslav (advisor)
This diploma thesis deals with computational modelling of the nanoindentation of tungsten with Berkovich indenter. In the beginning of thesis, research about nanoindentation test and Oliver-Pharr analysis is performed. The next part of thesis deals with deformation-stress analysis of the nanoindentation test with the linear-elastic model of material of tungsten and with comparison of results obtained with a diamond indenter and with an ideal rigid indenter. In the following model, plastic deformation is already considered. On the computational model with elasto-plastic model of material a sensitivity analysis of the influence of specimen and indenter dimensions and the influence of the penetration on results determined using the Oliver-Pharr analysis is performed. Furthermore, the applicability of the correction factors which were founded in the literature is assessed on this model and their exact value is determined. The last part of the work deals with the analysis of the influence of blunting of the indenter on results of the nanoindentation test and the comparison of different approaches for determining the projection of the contact surface.

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