Contents of Journal of Mechanical Engineering 52, 3 (2001)
O. DANEK: Parametric identification of forced vibration
of turbogenerator bladed rotors (in Czech) 129
CZ. J. JERMAK, M. RUCKI: Metrological properties of pneumatic gauge
with a capillary inlet nozzle 139
Justin MURIN: Implicit non-incremental FEM equations for non-linear
continuum 147
Jozef MURIN: Dynamic properties of a drive with hydrotransmissions
of new generation (in Slovak) 159
M. HOLECEK, P. KRAKORA: Scale-dependent continuum models
in biomechanics 175
Abstracts
Parametric identification of forced vibration of turbogenerator bladed rotors
O. DANEK
New concept of measurement and evaluation method for parametric
identification
of forced vibration of turbogenerator bladed rotors is developed with
ultimate
aim to explain the influence of aeroelastic couplings. Classical
measurements
of rotor vibrations in bearings are extended to selective measurements
of both
the bending and torsional dynamic deformations of the rotors as well
as
deformations of blade tips. Advanced novel feature of suggested method
is the
possibility to collect the data for identification at arbitrary row of
blades
in contrast to previous methods restricted only to locations of the
bearings.
Identification procedure for evaluation of measured data is proposed so
that
all possible operational regimes of turbogenerators are covered,
including
sudden unloading or short-circuit.
Metrological properties of pneumatic gauge with a capillary inlet nozzle
CZ. J. JERMAK, M. RUCKI
In the article, the idea and the results of a study of a pneumatic sensor with
the inlet nozzle formed as a capillary are presented. The flow characteristics
of the capillaries, the Reynolds number versus pressure and outflow
coefficient of the capillaries are determined, as well as flow coefficients of
the flapper-nozzle valve. For chosen pairs of the measuring nozzle and the
inlet capillary, the static characteristics are given and metrological
parameters analyzed. The investigation has proved that the gauges with an
inlet capillary use less pressured air than gauges with a common inlet nozzle
and have got of about 10% wider measuring range.
Implicit non-incremental FEM equations for non-linear continuum
Justin MURIN
The basic implicit incremental equations of the FEM for solution of non-linear
continuum mechanics problems are usually derived from the variational
principle after linearization of the Green-Lagrange deformation increment.
Linearized equations (with linearized stiffness matrix and linearized residual
forces) are solved by incremental-iterative methods (for instance
Newton-Raphson, etc.). In this contribution the non-incremental implicit
formulation of basic FEM equations for non-linear problems is presented. The
non-linearized system of equations for the non-incremental Lagrangian
formulation contains the full non-linear stiffness matrix of an element, from
which the full non-linear tangential stiffness matrix can be determined. This
formulation is applied to the derivation of basic FEM formulae for a 1D-bar
element.
Dynamic properties of a drive with hydrotransmissions of new generation
Jozef MURIN
In the paper dynamic properties of a drive with controlled Diesel motor, two
types of hydrodynamic transmission mechanisms of new generation and additional
gearing are investigated. For given mathematic model the time behaviour of
selected dynamic variables of the proper drive and hydrotransmission are
calculated at constant and monoharmonic loading. At calculation a modified
method of harmonic balance is applied.
Scale-dependent continuum models in biomechanics
M. HOLECEK, P. KRAKORA
A scale-dependent continuum model, in which the quantities of standard
continuum description are defined at two different scales (micro and macro),
is introduced and the general way of formulating such models is outlined. The
approach is used in biomechanics to model pressure dependence in blood
vessels. A simple analysis of the increase of blood pressure in dependence on
changes of the vessels' microstructure is given.