MODAL ANALYSIS OF A ROTATING SHAFT-DISK-BLADES SYSTEM WITH A CRACKED BLADE

摘要

The dynamic behavior of a rotating shaft-disk-blades systemrncontaining a cracked blade is investigated. With the crack releasedrnenergy, the flexibility due to crack is evaluated. An energy principlernin conjunction with the assumed-mode method is applied tornyield the discrete equations of motion. Numerical examples arerngiven for cases with between two and five symmetrically arrayedrnblades. The results show that there exist both torsion-bendingrncoupled modes and blade-coupling modes, which occur at repeatedrnfrequencies. When there is a cracked blade, the frequenciesrnof torsion-bending coupled modes decrease due to the crack, andrnblade-coupling modes have the phenomena of frequency bifurcation.rnFinally, the effects of shaft speed on the natural frequenciesrnare illustrated.