Method for predicting low-cycle fatigue life of titanium alloy material based on surface integrity

Abstract

The invention discloses a method for predicting the low-cycle fatigue life of a titanium alloy material based on the surface integrity. The low-cycle fatigue failure mode of the titanium alloy material under the pulling-pressing loading condition is considered, index parameters of the surface integrity serve as bases, a polynomial regression model is combined with a sine and cosine regression model, a predicting model for evaluating the low-cycle fatigue life of the titanium alloy material by adopting a combination of the surface roughness Ra and the maximum surface residual main stress sigmar is built, and finally a method for predicting the low-cycle fatigue life of the titanium alloy material based on the surface integrity is provided. By means of the method, the low-cycle fatigue life of the titanium alloy material can be easily, rapidly and accurately predicted, theoretical bases can be provided for reliable design of parts, practical production can be guided, and the certain engineering application value can be achieved.

Description

technical field [0001] The present invention relates to the prediction of the fatigue life of titanium alloy materials under tensile and compressive loads, in particular to a low-cycle fatigue aging method for titanium alloy materials based on surface integrity, which is suitable for widely used in automobiles, aerospace, ships and medical treatment Various titanium alloy materials. Background technique [0002] With the wide application of titanium alloys in the aviation industry, automobile industry, shipbuilding industry and medical fields, the problem of low-cycle fatigue damage of titanium alloys has become increasingly prominent, which seriously threatens the safety and reliability of titanium alloy structural parts. The complexity of the service environment and the variability of the load history of large mechanical structures such as aerospace equipment, ships, and rail vehicles may lead to sudden failure of the structure and sudden accidents. The safety of large-sc...

AI Technical Summary

Problems solved by technology

[0004] With the development of modern science and technology, the structure of titanium alloy mechanical products is becoming more and more complex, the performance parameters are getting higher and higher, and the working environment conditions are more severe. The contradiction between the traditional fatigue life prediction method of titanium alloy and engineering practice is gradually emerging. The reason is that The traditional deterministic methods cannot describe the objectively existing uncertain phenomena in engineering well.

Under actual service conditions, the workpiece is often subjected to uncertain loading conditions, therefore, the traditional fatigue life prediction method based on loading conditions will not be able to meet the needs of engineering development

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