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Simulation of stable crack growth in piping using comlete Gurson model
Korouš, Jan
The paper deals with simulation of stable crack growth using the complete Gurson model. The cracks were situated in a piping. An advantage of the complete Gurson model consists in the fact that the critical volume fraction for coalescence is not an input value, however it is calculated on the basis of Thomason's limit criterion of an material element with an internal void. The FEM system WARP3D was used for calculations and crack growth of cimcumferential and longitudinal cracks was simulated. In case of the longitudinal cracks, a specific crack growth was observed which is not proportional along the crack-tip length. The initial eliptical shape of the crack tip changes and becomes canoe-like one. This effect was experimentally observed and described in literature. It can be explained using stress triaxility distribution in front of the crack tip.
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Explicitní MKP analýza nárazu lidské lebky na tuhou podložku
Jiroušek, Ondřej
Article deals with explicit finite element modelling of contact conditions of human head impacting a flat rigid surface. For this purpose, detailed 3-D model of human skull and brain was developed based on a series of computer tomography scans of resolution 512x512 pixels taken at 1 mm distances. The FE model of human skull was filled with simplified model of human brain. The brain is modelled as a homogeneous viscoelastic material. A case study of low-velocity impact to different regions of the human head (e.g. frontal impact and impact in the occipital region) is also modelled.
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Numerical analysis of "sandwich" FE model of human skull
Kunecký, Jiří ; Jiroušek, Ondřej ; Jírová, Jitka
The paper reports on the reconstruction of FE model of human skull based on data obtained from Computed Tomography (CT) and its following numerical analysis. To improve the results the "sandwich" material model is used due to its better approximation of the bone structure. This improvement is achieved by covering the original model using shell elements. The thickness of the shell layer is tested and its final value is determined by comparing the results with different thicknesses to values obtained from experiments reported in scientific papers.
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Contact analysis of acetabular cup and pelvic bone
Vyčichl, Jan ; Jiroušek, Ondřej
A finite element study of factors influencing the contact stress in the pelvic bone after implantation of different designs of acetabular components is presented in the paper. The development of the geometry of the pelvic and the acetabular components is shortly described. The model is loaded according to a normal walk and the interaction of the components with subchondral bone is studied. The different designs of the cups are compared using the results of the contact analysis.
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Interaction of pelvic bone and acetabular component
Vyčichl, Jan ; Jiroušek, Ondřej ; Jíra, J.
The article deals with development and validation of complex FE model of pelvic bone and acetabular component. The model of pelvic bone is constructed on basis of CT data of high resolution. Different designs of acetabular components are then incorporated in the FE model using Boolean operations. Comparative study of different acetabular components (spherical, conical and spherical cemented) is presented. Contact stresses in the underlying pelvic bone are compared for each of the cup designs.
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