Browsing by Subject "crack"

Now showing 1 - 4 of 4

Access status: Open Access ,
A new vibroacoustic method for shaft crack detection
(Wydawnictwa AGH, 2007) Gosiewski, Zdzisław; Sawicki, Jerzy Teodor
Various excitation techniques have been developed to extract information on dynamic state of rotating machinery. This paper will address the effectiveness of selected excitations and analysed signals towards health monitoring of rotating machines from the shaft crack point of view. The computer simulation study is based on the uncracked and cracked Jeffcott rotor models and the efficiency of the selected approaches is examined. As the excitation we have considered the rotor unbalance, additional harmonic forces, and input conditions. The combined resonances as diagnostic indicators of the cracked shaft are good seen in the total frequency spectrum in the case when we consider the difference between the spectra of cracked and uncracked shaft. We have also introduced a new model of the rotor which allows us to use different method of signal processing for the crack detection and the evaluation of its deep. So more, in such model we can take into account the number of excitation planes and directions of the applied forces, the choice of the analysed signals (e.g. transient, steady-state).
Access status: Open Access ,
Crack indicators for large power turbo-set monitoring and diagnostic system
(Wydawnictwa AGH, 2005) Kiciński, Jan; Banaszek, Sławomir
Active elements in power machine may be controlled with a signals from diagnostic system to stabilize it's operating in a case of emergency work. It needs to identify specific indicators for particular classes of defects. The paper presents possibilities to define such indicators for transverse crack occurring in the rotor of 200 MW turbo-set. The investigations were performed in the way of computer simulations utilizing the NLDW computer code. It bases on non linear model of bearings and Knott crack model. Crack propagation influence on the machine's dynamic state was examined. A resonance being a function of crack depth was detected. The amplitude and phase spectra were discussed as crack indicators as well as torsional/axial vibrations couplings.
Access status: Open Access ,
Identyfikacja pęknięcia belek na podstawie pomiarów amplitud drgań wymuszonych
(Wydawnictwa AGH, 2005) Majkut, Leszek
This paper deals with detection of the location and size of a transverse crack in beam like structure. An input quantity for identification a forced vibration amplitudes was chosen. For this quantity the inverse beam model was created. Identification algorithm based on this model was proposed.
Access status: Open Access ,
Identyfikacja pęknięcia w belkach na podstawie pomiaru częstości drgań własnych
(Wydawnictwa AGH, 2005) Majkut, Leszek
This paper deals with detection of the location and size of a crack. An input quantity for identification a natural frequencies was chosen. For this quantity the inverse beam model was created. Computer algorithm for making identification based on this model was proposed.