RAJI, A., HASNAOUI, M., BAHLAOUI, A., NAÏMI, M., EL AYACHI, R.: Mixed convection in inclined channels with localized heating blocks 185 GRZEGOŻEK, W., NOGOWCZYK, P.: Analysis of the influence of selected motion parameters of a vehicle on steering effort 201 BALLO, I., CHMÚRNY, R.: Critical speed passage of a flexible slender rotor by re-tuning 216 BEDNARCZYK, J., GŁUCH, G.: Stress and strain states of inductor coils used for electrodynamic machining of metals 228
ABDELGHANI RAJI, MOHAMMED HASNAOUI, AHMED BAHLAOUI, MOHAMED NAÏMI, RACHID EL AYACHI
WITOLD GRZEGOŻEK, PAULINA NOGOWCZYK
IGOR BALLO, RUDOLF CHMÚRNY
The paper analyses the flexural vibration of an elastic rotor with linear elastic supports during its first critical speed passage. Before its critical speed passage, the system will be re-tuned in a linear fashion, i.e. the support stiffness will be linearly decreased.
The mathematical model is formulated using the Large Finite Element Method. The matrix equation thus generated is then transformed to the standard form based on a small parameter theory. The solution of this system of equations yields the transient phenomena time dependence and the corresponding stationary state.
Numerical results are presented in two ways. Firstly, the time dependence of the maximal amplitude of rotor transversal deflection during the passage is given. Secondly, the dependence of the largest amplitude of the rotor transversal deflection at the precise start and termination of the re-tuning is presented.
JÓZEF BEDNARCZYK, GERARD GŁUCH
The paper presents the results of research on strength of inductors used as tools in electrodynamic machining of pipes, carried out at the AGH-University of Science and Technology in Cracow. The paper describes the nature of volumetric Lorentz forces acting on the coils of compressing and expanding inductors, followed by the determination of stress and dislocation patterns formed in coils by Lorentz forces using the methods of numerical finite elements. Discussed issues are essential when designing durable inductors for industrial purposes