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http://hdl.handle.net/11025/30253
Fri, 01 Mar 2024 00:15:15 GMT2024-03-01T00:15:15ZConstitutive modelling of an arterial wall supported by microscopic measurements
http://hdl.handle.net/11025/1312
Název: Constitutive modelling of an arterial wall supported by microscopic measurements
Autoři: Vychytil, Jan; Kochová, Petra; Tonar, Zbyněk; Kuncová, Jitka; Švíglerová, Jitka
Abstrakt: An idealized model of an arterial wall is proposed as a two-layer system. Distinct mechanical response of each
layer is taken into account considering two types of strain energy functions in the hyperelasticity framework. The
outer layer, considered as a fibre-reinforced composite, is modelled using the structural model of Holzapfel. The
inner layer, on the other hand, is represented by a two-scale model mimicing smooth muscle tissue. For this model,
material parameters such as shape, volume fraction and orientation of smooth muscle cells are determined using
the microscopic measurements. The resulting model of an arterial ring is stretched axially and loaded with inner
pressure to simulate the mechanical response of a porcine arterial segment during inflation and axial stretching.
Good agreement of the model prediction with experimental data is promising for further progress.Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/11025/13122012-01-01T00:00:00ZVychytil, JanKochová, PetraTonar, ZbyněkKuncová, JitkaŠvíglerová, JitkaEnergy transformation and flow topology in an elbow draft tube
http://hdl.handle.net/11025/1310
Název: Energy transformation and flow topology in an elbow draft tube
Autoři: Štefan, David; Rudolf, Pavel; Skoták, Aleš; Motyčák, Lukáš
Abstrakt: Paper presents a computational study of energy transformation in two geometrical configurations of Kaplan turbine
elbow draft tube. Pressure recovery, hydraulic efficiency and loss coefficient are evaluated for a series of flow
rates and swirl numbers corresponding to operating regimes of the turbine. These integral characteristics are then
correlated with local flow field properties identified by extraction of topological features. Main focus is to find the
reasons for hydraulic efficiency drop of the elbow draft tube.Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/11025/13102012-01-01T00:00:00ZŠtefan, DavidRudolf, PavelSkoták, AlešMotyčák, LukášDesign of a large deformable obstacle for railway crash simulations according to the applicable standard
http://hdl.handle.net/11025/1309
Název: Design of a large deformable obstacle for railway crash simulations according to the applicable standard
Autoři: Špirk, Stanislav; Kemka, Vladislav; Kepka, Miloslav; Malkovský, Zdeněk
Abstrakt: This article discusses the design of a deformable obstacle to be used in simulated rail and road vehicle collisions as
prescribed by scenario 3 specified by standard ČSN EN 15227. To approve a vehicle in accordance with this standard,
it is necessary to carry out numeric simulations of its collision with a large obstacle, following the standard’s
specification. A simulated impact of a rigid ball into the obstacle is used to calibrate the obstacle’s properties, and
the standard specifies limit deformation characteristics for that collision. The closer are the deformation characteristics
observed in the test to the limit characteristics prescribed by the standard, the more favorable results can be
expected when using the obstacle in actual numeric simulations of frontal impacts of rail vehicles. There are multiple
ways to design a FEM model of the obstacle; this article discusses one of those. It shows that given a suitable
definition of material properties, this particular approach yields quite favorable deformation characteristics.Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/11025/13092012-01-01T00:00:00ZŠpirk, StanislavKemka, VladislavKepka, MiloslavMalkovský, ZdeněkBending and free vibration analysis of thick isotropic plates by using exponential shear deformation theory
http://hdl.handle.net/11025/1308
Název: Bending and free vibration analysis of thick isotropic plates by using exponential shear deformation theory
Autoři: Sayyad, Atteshamuddin Shamshuddin; Ghugal, Yuwaraj M.
Abstrakt: This paper presents a variationally consistent an exponential shear deformation theory for the bi-directional bending
and free vibration analysis of thick plates. The theory presented herein is built upon the classical plate theory.
In this displacement-based, refined shear deformation theory, an exponential functions are used in terms of thickness
co-ordinate to include the effect of transverse shear deformation and rotary inertia. The number of unknown
displacement variables in the proposed theory are same as that in first order shear deformation theory. The transverse
shear stress can be obtained directly from the constitutive relations satisfying the shear stress free surface
conditions on the top and bottom surfaces of the plate, hence the theory does not require shear correction factor.
Governing equations and boundary conditions of the theory are obtained using the dynamic version of principle
of virtual work. The simply supported thick isotropic square and rectangular plates are considered for the detailed
numerical studies. Results of displacements, stresses and frequencies are compared with those of other refined
theories and exact theory to show the efficiency of proposed theory. Results obtained by using proposed theory are
found to be agree well with the exact elasticity results. The objective of the paper is to investigate the bending and
dynamic response of thick isotropic square and rectangular plates using an exponential shear deformation theory.Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/11025/13082012-01-01T00:00:00ZSayyad, Atteshamuddin ShamshuddinGhugal, Yuwaraj M.