Calculation method of metal structure fatigue life

Abstract

The invention discloses a metal structure fatigue life calculation method based on a material corrosion damage factor and a weld crack damage factor.Damage factors of two factors of corrosion and weldjoint of the steel structure to the yield strength of the steel structure are obtained; finally, the yield limit of the material after aging along with time is solved; a model of the steel structureyield characteristics changing along with time is established by utilizing the factors, so that the reliable yield strength limit of the steel structure is obtained, an intersection point exists at acertain position by utilizing a steel structure S-N curve considering damage factors and a stress cycle, and the intersection point is a residual service life value needing to be predicted by people.According to the method, the influence of corrosion and weld crack damage on the metal structure of the hoisting machine in actual use is fully considered, and a material corrosion factor and a weld crack damage factor are introduced, so that a calculation result is more practical and accurate, and the method is suitable for application of metal structure safety assessment.

Description

technical field [0001] The invention relates to the technical field related to fatigue life calculation of metal structures of hoisting machinery, in particular to a method for calculating the fatigue life of metal structures based on material corrosion damage factors and weld crack damage factors. Background technique [0002] Most of the mechanical parts in engineering equipment are subjected to alternating loads. Under the action of alternating loads, some parts with high stress or defects will be damaged and gradually accumulated, resulting in functional degradation, which is manifested as the failure form of crack initiation, expansion and complete fracture. [0003] The failure of lifting machinery can be caused by one or more processes, and its failure form can be a single process phenomenon or a combination of process phenomena, and the result is a characterization of a macroscopic phenomenon. For example, corrosion is generally considered to be a single process, an...

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Problems solved by technology

[0004] In the fatigue life calculation process of metal structures commonly used in the existing lifting machinery, the material corrosion damage factor and the weld crack damage factor are considered independently, and the synergistic damage process of the two is not considered at the same time. Therefore, in the life During the forecasting process, there is a large deviation from the actual working environment.

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