Patent ID: 8504338
Filing Date: 2013-08-06
Classification: G01H

Abstract:
1. A computer implemented measuring method of mechanical fatigue in turbo-unit shafting, comprising the steps of: 1) determine a lumped mass model and model parameters of a turbo-unit; 2) compute, using a computer, torsional mode frequency and vibration curve based on the mass model; 3) record real-time changes of terminal palstance Aw, then record changes of palstance Δω1, Δω2, Δω3 . . . , Δωn in different modes by filtering, and then compute, using the computer, terminal rotation angle of each mode Δθ where (k=1, 2, 3, . . . n) ω A f 4) using the mode frequencies, vibration curve and equivalent spring constants of the lumped mass model of the turbo-unit, calculate, using the computer, a torque on each cross-section of the shafting in each mode by multiplying Δθ 5) find out stress cycle in the history plot for the torque on each cross-section of the shafting, and compute, using the computer, equivalent stress magnitude corresponding to each stress cycle; 6) look up Stress-Fatigue Life curve for dangerous cross-sections so as to obtain fatigue damage value caused by a single stress cycle; and 7) compute, using the computer, a cumulative fatigue value of all cross-sections of the shafting caused by a specific vibration, namely the mechanical fatigue of the turbo-unit shafting.