Fatigue notch coefficient data processing method considering corrosion and residual stress

Abstract

The invention belongs to the technical field of structural life reliability evaluation in a corrosive environment, and discloses a fatigue notch coefficient data processing method considering corrosion and residual stress. The method includes: reconstructing a notch surface geometric model; actually measuring the residual stress distribution of the notch part of the structural simulation piece byadopting an ultrasonic residual stress tester; obtaining a fitting calculation formula of the residual compressive stress along the depth direction through data fitting; establishing a finite elementtheoretical analysis model by adopting a reverse modeling technology, carrying out mesh generation, and obtaining a stress concentration coefficient through analysis; and obtaining the stress concentration coefficient under the corrosion condition based on analysis. The theoretical calculation method provided by the invention better conforms to the actual condition of structure service, and the prediction precision of the fatigue life is obviously improved. According to the method, the influences of corrosion damage and residual stress caused by the microstructure, the structural boundary dimension and the environment of the material can be considered, and the fatigue notch coefficient calculation method provided by the invention is wider in application range and good in universality.

Description

technical field [0001] The invention belongs to the technical field of structural life reliability evaluation in a corrosive environment, and relates to a fatigue notch coefficient data processing method considering corrosion and residual stress. Background technique [0002] At present, accurate prediction of structural fatigue life under service corrosive environmental conditions is crucial for safe use. Fatigue notch factor K f is a very important parameter in structural fatigue life assessment, and its definition is [0003] [0004] Determining the fatigue notch factor K f The most direct and reliable method is to pass the fatigue test. Due to the different structural forms, the size of the structural simulation parts is different, and the surface finish is different. K f They are different, and it takes a lot of manpower, material and financial resources to carry out such a test, so the fatigue notch coefficient K is determined through the test f is unrealistic....

AI Technical Summary

Problems solved by technology

[0008] Through the above analysis, the problems and defects in the prior art are: (1) the current analysis method of the fatigue notch coefficient cannot consider the influence of corrosion damage; (2) the current existing analysis method of the fatigue notch coefficient cannot Consider the influence of residual stress caused by shot peening; (3) The existing analysis method of fatigue notch coefficient cannot consider surface defects

The above factors lead to inaccurate calculation results of the traditional fatigue notch coefficient calculation method, which leads to inaccurate fatigue life evaluation results and affects the safety of the structure.

[0009] The difficulty of solving the above problems and defects is: corrosion damage has a great influence on fatigue life

The corrosion damage caused by service environment conditions is random. Different environments and different materials cause different degrees of corrosion. At present, there is no theoretical method that can accurately characterize the corrosion damage of the notch; the conventional finite element analysis method cannot effectively consider The influence of material residual stress, reasonable characterization of corrosion damage and the influence of residual stress is very important for the accuracy of the calculation of fatigue notch coefficient, and the current methods cannot consider the above factors

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