National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Vibration of blade bunch forced by delayed excitation
Půst, Ladislav ; Pešek, Luděk ; Radolfová, Alena
Response of the five-blade-bunch linked in the shroud by means viscous-elastic damping connections and excited by running harmonic forces is investigated. This type of excitation corresponds to the real excitation in the steam or gas turbine with different number of rotor and stator blades. After ascertaining of phase delay between neighbouring blades, the different dynamic properties of isolated and closed five-blade bunch are shown and analysed in this contribution. Recommendation how apply ascertained results for evaluation of experimentally gained data from dynamic measurements on bladed disk is added.
Free vibration of planetary gearing
Půst, Ladislav ; Pešek, Luděk ; Radolfová, Alena
Planetary gear drives have important advantages over parallel axis gears due to theirs compact design an great torque-to-weight ratio, but dynamic properties of such gearings are more complicated and they need deep dynamic analysis. For improving load sharing among planet wings, the application of flexible planetary pins or using free central wheel is needed. Presented paper is oriented on mathematical model design. The plane type of gearings with four planetary subsystems and fixed planet carrier has been selected. Used helical gearing has an essential smaller variation of contact stiffness against the direct spur gearings. Therefore this stiffness variability is not taken into account. Frequency and modal spectrums of such a dynamic mathematical model of planetary gearing set is presented and influences of design parameters are analysed.

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