| 摘要 |
PURPOSE: To reduce the vibration and cracking of a column by arranging in the column a means for damping the vibration of the column, resulting from air flow pressure pulses from a fan to cause vibration of the column, when a fan blade is operated at no less than a transonic velocity. CONSTITUTION: During operation when a fan blade is operated at a transonic velocity or at a ultrasonic velocity, multiplex pure sound is generated by the physical vibration of a first stage blade assembly 18. The multiplex pure sound is conveyed forward to excite or vibrate a column 26. Bending (deflection) and/or torsional motion is caused in a column wall 36. As the result of the motion, a damper 56 is deflected so that at least part of friction liners 58, 60 is scrubbed to the column wall 36 in a contacting relation. The liners 58, 60 thus absorb and disperse energy generated by the excitation of the column 26. The damper assembly 54 therefore causes coulombic damping to disperse energy on an interface between the damper assembly 54 and the column wall 36.
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