ANALYSIS OF STRESS-STRAIN STATE OF BUCKET WHEEL EXCAVATOR REVOLVING PLATFORM STRUCTURE - FUNDAMENT OF EFFICIENT RECONSTRUCTION

Bucket wheel excavators (BWE) are a part and parcel of the mechanization system in open pits. Their exploitation in heavy duty conditions causes failures of supporting structural parts (plastic deformations, cracks, fractures, breakages). As a real example, the paper first presents appearance of typical damages of revolving platform structures for BWE TAKRAF SRs 1200x24/4 (400 kW) + VR. Subsequently, techniques for calculating their structure are presented, whose basis is made in two stages: set up of finite element mesh and analysis of loads. The structural solution is developed by conducting the presented calculation procedure, and is applied during reconstruction of revolving platforms (2005) on two BWEs mentioned before. Validity of problem approach and efficiency of reconstruction solution is found in the fact that after reconstruction and repair BWE have excavated more than 5 000 000 m(3) of barren soil, while at reconstruction zones no defects of revolving platform structures have been detected.