Identification of Crack Initiation Cause in Pylons Construction of the Excavator SchRs630

摘要

A crack occurred on gusset plate of pylon vertical truss of bucket wheel excavator (BWE) SchRs630. Numerical calculation model of pylons, slewing platform and undercarriage was formed. Calculations are done using finite element method (FEM) for different load cases. It was determined that the inertial forces caused by bucket wheel boom and counterweight boom masses while breaking slew drive cause the stress concentration in this spot. To complete the whole picture of the structure behaviour dynamic analysis was performed. Based on calculation and distribution of potential and kinetic energy on oscillation modes, using the reanalysis method, redesign of this part of the structure was proposed. The stress was reduced by over 20 % by the proposed redesign solution.