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MKP analýza únosnosti vícevrstvého železničního podloží
Jiroušek, Ondřej ; Kunecký, Jiří ; Jíra, J. ; Horníček, L.
Numerical investigation of bearing capacity of railway substructure using finite element method and laboratory experiments is presented. A set of parametric FE models is built and unified approach for assessment of bearing capacity of the construction presented. Results are presented in terms of design graphs, where for every type of substructure design resulting bearing capacity is evaluated. Presented methodology is easily extensible for reinforcing effects of layer inclusion, geogrid placement or use of cemented layers.
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MKP analýza poranění hlavy během dopravní nehody
Kunecký, Jiří ; Jiroušek, Ondřej
The work is based on the Visible Human Project. Impact acceleration history is taken from MADYMO accident simulation. For the solution LS-DYNA software is used.The paper shows possibility to use detailed finite element model of human head to predict or describe injuries during mechanical loading as in this case of a traffic accident. The possibility of using combination of rigid body modeling of the whole situation together with detailed FE model of the region of interest is highly advantageous. However, the model should be verified in large number of reconstructions.
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Zjišťování materiálových vlastností houbovité kostní tkáně optickou metodou
Kytýř, Daniel ; Jiroušek, Ondřej ; Žák, Ondřej
Article deals with material properties of spongy bone assessed by optical identification based on surface texture registration.Strains at the specimen surface were measured using high-resolution CCD camera and optical identification method was used to trace their position during deformation. Centres of gravity of the markers are then considered to be vertices of connected triangles for which fields of displacement and strain are calculated. The assessed displacements of the structure of trabecular bone are used to obtain strain-stress diagram.
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Rekonstrukce kraniocerebrálního poranění pomocí metody konečných prvků
Jiroušek, Ondřej ; Brichtová, E. ; Jírová, Jitka
The paper deals with reconstruction of a sport accident using detailed FE model of skull and brain is presented in the paper. The sport accident involved a 12-year old boy on whom a handball cage fell during school sport activity. FE model of human head was developed using series of CT scans obtained postsurgically. Rigid body model was used to assess initial conditions at the moment of the impact which were used in finite element modeling of the head impact. The detailed FE model was imposed to the initial conditions obtained just before the head impacted the playground. The pressure, shear stress response, von-Mises stress response and logarithmic strain values were evaluated in four regions: (i) frontal, (ii) parietal, (iii) occipital and (iv) midbrain region. For the head injury assessment a criterion based on the criterion proposed by Miller et al. in 1998 is applied. Results from the numerical analysis of the accident showed good agreement with clinically observed head injuries.
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Nové kritérium pro stanovení poškození hlavy
Jiroušek, Ondřej ; Jírová, Jitka ; Brichtová, E.
Detailed Finite Element Model of human head used for head injury assessment is presented in the article. Development of the model based on a series of postoperative CT images of high resolution is shortly described. The model is used in a model situation of a sport accident involving a 12-year old boy on whom a handball cage fell during a sport activity causing a serious injury of the boy’s head. An approach to quantify the injuries caused is described in the paper.
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