Current Flexible Rotor-Bearing System Balancing Techniques Using Computer Simulation

As the cost of machinery has risen and the need for dependability, safety and increased performance have in a similar manner increased, the needs of industry for viable flexible rotor balancing techniques has no less increased. Various flexible rotor methods have been advocated for supercritical shafting, but few studies or comparisons have appeared in the open literature. Among the procedures for balancing large and/or high speed (supercritical) rotors are the N modal method of Bishop and Gladwell, the N + B modal of Federn, the N and + B simultaneous modal method of Kellenberger, and the influence coefficient method of Lund and Rieger. Each of the aforementioned balancing techniques is examined and explained in detail. The first known modal balancing programs are listed and described. Using these programs as a basis, the influence coefficient method of Lund and Rieger is compared to the modal methods of Bishop and Gladwell, Federn, and Kellenberger. The companies are made with the aid of a Prohl based unbalance response computer program. The rotor systems used for the comparison are flexible shafts, some mounted in damped bearings, and some mounted in undamped bearings. One sample system exhibits rigid body behavior in addition to flexible behavior. These examples form the basis of the first known direct computer based comparison between a current influence balancing technique and the highly developed and distributed modal methods