DSpace Kolekce:
http://hdl.handle.net/11025/1786
2024-03-29T14:36:25ZAn improved method for estimating fatigue life under combined stress
http://hdl.handle.net/11025/1831
Název: An improved method for estimating fatigue life under combined stress
Autoři: Balda, Miroslav; Svoboda, Jaroslav; Fröhlich, Vladislav
Abstrakt: The paper deals with a complicated problem of estimating fatigue lives of machine parts exposed to various
kinds of dynamic loading. An origin of the presented method can be found 25 years ago when a simple algorithm
of strain energy density cumulation was applied for evaluation of uniaxial harmonic and random fatigue tests.
Recently, the method has been adopted for multiaxial loading. Unfortunately, results of its application have shown
rather big variance. This paper presents the improved method, which yields much lower scattering of estimated
fatigue lives compared with earlier approaches.2007-01-01T00:00:00ZBalda, MiroslavSvoboda, JaroslavFröhlich, VladislavThe problems at investigation of state of stress of thick orthotropic plate
http://hdl.handle.net/11025/1830
Název: The problems at investigation of state of stress of thick orthotropic plate
Autoři: Červená, Olga; Hora, Petr
Abstrakt: The determination of state of stress of thick orthotropic plate is outlined here. The analytical formulations
of dispersion curves for arbitrary direction of wave propagation in orthotropic plate, which we defined earlier, are
used to obtain results. The false roots appearing in the numerical computation of thick plate dispersion curves
from orthotropic materials are mentioned. The displacements and the stresses of the thick orthotropic plate are
presented too.2007-01-01T00:00:00ZČervená, OlgaHora, PetrThe influence of the notches on the natural frequencies
http://hdl.handle.net/11025/1829
Název: The influence of the notches on the natural frequencies
Autoři: Dekýš, Vladimír; Kopas, Peter; Mazúr, Ján; Malcho, Milan
Abstrakt: The simplification of the FEM model (the missing of a notch or a crack) generally means the modification of
the natural frequencies. An analysis of these changes is matter of this paper. The direct and semicircle notches
were made on the testing specimens (by cut depth in the specimens) and the naturals frequencies were measured
and computed. The results are compared.
In the paper is discussed the choice of the FEM element for FEM model and the comparison with
experiment is made too.
The influence of the crack on the natural frequencies is discussed in the case of specimen for high cycle
fatigue test. The changes of the first three frequencies are compared for specimens with and without crack.2007-01-01T00:00:00ZDekýš, VladimírKopas, PeterMazúr, JánMalcho, MilanA stochastic response of vibrating systems containing random parameters
http://hdl.handle.net/11025/1828
Název: A stochastic response of vibrating systems containing random parameters
Autoři: Dupal, Jan; Králíček, Jan
Abstrakt: The paper deals with an approach to the response limit estimation of the vibrating systems in the transient
state. A gradient and perturbation methods for derivatives of the response with respect to the random parameters
are shown. This sensitivity analysis can be performed for linear systems in the analytical way or in numerical
way for both linear and nonlinear systems. In case of nonlinear systems it is supposed small deviations of
random parameters from hyperbolic point of the system and that no bifurcations and changes of phase portrait
will occur.2007-01-01T00:00:00ZDupal, JanKrálíček, Jan