Engineering Method for Assessing the Residual Life of Machines' Complex Metal Structures Based on Crack Resistance

摘要

The authors present the experience of applying their methodology for calculating the residual life of metal structures of reloading machines by the criterion of the development of fatigue cracks to a critical size. The methodology is based on the well-known calculated dependencies of fracture mechanics, refined and supplemented with elements that take into account the specifics of the operation of transshipment machines in difficult weather conditions. Particular attention was paid to the accuracy of determining the stresses in the metalwork element when performing working operations because of the ever changing of the load acting on the metalwork, depending on the weight of the lifted load and the position of the machine in space. To confirm the high sensitivity to the accuracy of the determination of stresses, the dependence of the influence of the resource element metal with a crack from the amplitude of stress is graphically presented. The methodology for assessing the residual resource has been successfully tested on a number of complex metal.