Fatigue residual life prediction of casting crane under track defect model

摘要

For the safety problems caused by abnormal changes of stress-time history at fatigue risk points of casting crane metal structure due to the vertical impact effect of track defects, the forecast method of fatigue residual life of casting crane under track defect model is proposed. Guided by the kinematics and dynamics theory, the kinematic-dynamic model of dynamic load resulted from crane travelling on defective track including the high-low dislocation and horizontal gap is established. The influence of track defects on the vertical impact effect of operation crane is analyzed. Furthermore, combining with the collection of technological process and usage of casting crane, the characteristic parameters needed in the process of stress spectrum acquisition are determined. The allowable stress method combined with finite element simulation is used to get the fatigue risk cross-sections and points of crane metal structure and the first principal stress-time histories of dangerous points are obtained. The double parameter stress spectrum of dangerous points is extracted by rain flow technology. Based on fracture mechanics and damage tolerance design, the fatigue residual life of dangerous points is estimated by Paris formula. Taking the 100/40t-28.5m casting crane as an example, the feasibility of the above model and method is verified.