Experimental Study on Acoustic Emission Detection for Low Speed Heavy Duty Crane Slewing Bearing

摘要

By use of the custom-built crane model, AE instrument and loads, a large amount of experiments have been done. For all AE signals acquired from the slewing bearing with no defect and with defect on different operation mode, AE signal parameter distribution analysis, AE signal parameter correlation analysis, AE signal frequency spectrum analysis have been achieved. The AE parameter distribution range for signals acquired from the slewing bearing with defect is much wider than that for those from the slewing bearing with no defect. By observing energy–duration correlation diagram, the defect signal can be identified evidently. Through frequency spectrum analysis, it can be found that the defect will lead to high frequency signal. In addition, the statistical analysis method is used to investigate the AE characteristics of the non-defective slewing bearing and defective slewing bearing. The statistical results of AE parameters are obtained respectively under different load and rotation speed of slewing bearing. Hits sum and energy sum of AE signal acquired from the slewing bearing with defect are much higher than the values acquired from the slewing bearing with no defect, and they increase with loads increasing. The maximum amplitude, hits sum, energy sum of AE signal acquired from slewing bearing with defect are all higher than those acquired from the slewing bearing with no defect regardless of rotation speed.