DIAGNOSTIC METHOD AND RISK EVALUATION METHOD FOR TENDENCY OF LOW-CYCLE FATIGUE DAMAGE OF EQUIPEMENT

摘要

PROBLEM TO BE SOLVED: To provide a diagnostic method for tendency of "low"-cycle fatigue damage resulted from thermal stress at the time of starting/stopping equipment such as a device constituting a boiler, and an evaluation method based on risk of the "low"-cycle fatigue damage.;SOLUTION: The tendency index (breakage probability) of damage is calculated on the basis of the temperature T of the equipment, a starting/stopping frequency N, an equipment-specific breakage factor F determined depending on the presence/absence of a stress collection part or a welding part, a Young's modulus E, and a fatigue life determined by the material of the equipment, whereby the tendency of the "low"-cycle fatigue damage due to thermal stress at the time of starting/stopping the equipment can be diagnosed. A RBM (risk-based maintenance) method for evaluating the risk of the equipment while taking the resulting tendency of low-cycle fatigue damage as the vertical axis and the degree of influence as the horizontal axis is executed, and the result is served for the preservative maintenance of the equipment.;COPYRIGHT: (C)2005,JPO&NCIPI