The aim of the paper is modal condensation of a system which represents bladed disk. These kinds of systems are mainly used in steam turbines what is the topic of the article. The model of the bladed disk is based on decomposition into a disk subsystem and a blading subsystem. The finite element method is used for modeling of the both subsystems. All influences of steady-state rotation are respected as centrifugal forces, gyroscopic effects, centrifugal stiffening of blades and dynamic softening. Blades are modeled by using ID elements and the disk is modeled by using 3D hexahedral elements. Modal condensation is applied to a disk subsystem. Different levels of the condensation are presented and compared on a testing bladed disk. and Obsahuje seznam literatury
The article provides a method of mathematical modelling of the dynamic properties of the electric locomotive wheelset drive. The linkage of the traction motor by means of the rotor pinion gear with the gear of wheelset drive is considered. The impact of couplings and operation conditions on the dynamic properties is studied. The method of decompositon into subsystems is applied for derivation of mathematical model of an interconnected system. This model is used for the calculation of modal values and also for investigating the forced vibration excited by pulsation moments of the asynchronous traction motor. The method is applied to a particular drive of the locomotive SKODA 109E. and Obsahuje seznam literatury
Gearboxes and similar machines containing rotating parts are complex systems with complicated structure and couplings. Generally they can be decomposed into more simple subsystems. These subsystems are usually rotating shafts with gears joined
by gear couplings and housing coupled with rotating shafts by bearings. The paper is aimed at the mathematical modelling of gearboxes with spur helical gears considered including their interior rotating shaft system and housing. The used bearing model
respects real number of rolling elements and roller contact forces acting between the journals and the outer housing. The model of a complete gearbox is created using the modal synthesis method. The kinematic transmission errors in gear couplings are viewed as sources of excitation. Vibration and noise analysis of the gearbox housing is performed by means of the created model. Four types of objective functions suitable for optimization from the radiated noise point of view are proposed. The presented methodology is applied to the simple test-gearbox. and Obsahuje seznam literatury
The aim of the paper is to show the influence of design parameters on the suppression of rotating blade vibration. The derivation of nonlinear mathematical model of a blade couple mutually connected by a friction element is summarized. After that, the linearization of the mathematical model is performed by harmonic balance method. The linearized model is used for sensitivity analysis of real and imaginary parts of eigenvalues in the course of rotation and sensitivity analysis of stead-state response with respect to the design parameters of internal friction coupling. and Obsahuje seznam literatury
The paper deals with mathematical modelling and computer simulation of the seismic response of chosen components of hte nuclear WWER 1999 reactor. The seismic response is investigated by numerical integration method in time domain. The seismic excitation is given by two horizontal and one vertical synthetic accelerograms at the level of the pressure vessel seating adjusted for a certain damping vallue 5 %. The main aim of the paper is seismic response assessment for two variants of nuclear fuel assemblies - VVANTAGE 6 and TVSA-T. The maximal values of displacements and linkages or component deformations are compared for both fuel assembly variants. and Obsahuje seznam literatury