Cracks, repair and reconstruction of bucket wheel excavator slewing platform

Abstract

This paper discusses the results of the investigation of occurrence of cracks in the structure of bucket wheel excavator (BWE) slewing platform, the repair procedure and the reconstruction of the slewing platform. The results of the finite elements analysis (FEA) point out the pronounced stress concentration in the zones of crack occurrence. The values of calculated stresses in the said zones exceed the yield stress of the material. The design solution for the slewing platform reconstruction is chosen based on the comparative analysis of stress-strain states of alternative solutions. The adopted solution enabled the repair and reconstruction in field conditions, without previously dismantling components of the BWE superstructure. Moreover, the regular maintenance procedure has not been impeded. Experimental analysis of the stress state of the reconstructed slewing platform in regular working conditions has confirmed the validity of the reconstruction design. After the reconstruction the BWE has dug up more than 2.9 x 10(6) m(3) of overburden. Visual inspection of slewing platform proved that there are no defects in the structure.