‘Design-in’ Faults - the Reason for Serious Drawbacks in High Capacity Bucket Wheel Excavator Exploitation

Abstract

This paper describes the failure analysis results of undercarriage and superstructure vital subassemblies, which led to periodical stoppage and eventually total collapse of the bucket wheel excavator (BWE) SchRs 1760, once the machine with the highest theoretical capacity operating on the overburden excavation in open pit mine “Kolubara” - Serbia. It is conclusive that the main cause of two wheel bogie structural failure, described as case 1, is its insufficient strength during the action of lateral forces which are dominantly applied during the BWE curve travel. Case 2 analyses the support structure of portal tie-rods failure which was the consequence of superposition of the negative effects caused by inadequate shaping and dimensioning of the support assembly for given load conditions, as well as influences of defects of the metal weld structure. Both of the described failures are caused by the design-in faults.