NUMERICAL ANALYSIS OF FATIGUE FOR THE ASSESSMENT OF REMAINING SERVICE LIFE OF THE ERC 1400-30/7 BUCKET WHEEL EXCAVATOR

This paper deals with the issue of the service life of the boom of a bucket wheel excavator (BWE) in a lignite open-pit, solved through a fatigue analysis with the aid of the SolidWorks application. To this purpose, the boom of the excavator, which is a spatial structure of a truss type, has been modelled in compliance with the geometrical and material conditions of the real system. For the beginning the linear dynamic time response was determined for a load produced by the excavation forces, with a global damping of 2%. The results of the analysis allowed for the determination of the deformations which occur and their frequency. Then the model underwent a static strain analysis with the established deformations to determine the stress generated by the excavation process, whose results cause the events which produce the fatigue. The frequency of the oscillations (vibrations) corroborated with the estimated or actual number of hours of service within a year determines the number of events that cause fatigue. Proceeding from these, the analysis of the fatigue status corresponding to a period of excavation of 10 to 30 years has been determined. Making the fatigue calculations with the aid of the SolidWorks application, it is possible to evaluate the degree of damage according to the period of exploitation, which determines the remaining service life of the BWE boom.