High-temperature structure dangerous point stress-strain calculation method

Abstract

The invention discloses a high-temperature structure dangerous point stress-strain calculation method, aims to solve the problem of notch stress-strain overestimation in the Neuber criterion, adopts an effective stress concentration coefficient to calculate pseudo stress, and improves the calculation method of the effective stress concentration coefficient. In addition, the proposed notch correction method is combined with a Caboch unified viscoplasticity constitutive model, and the stress-strain state of the dangerous point under the heat engine load is estimated. In order to evaluate the reliability of the method, an estimated result is compared with a nonlinear finite element analysis result, and the result shows that the method can accurately estimate the notch stress and strain underthe multi-axis thermal-mechanical cyclic load. The method is of great significance in guaranteeing the life prediction accuracy of structural parts in actual engineering, safety service of various important devices and accurate life extension.

Description

technical field [0001] The invention belongs to the theoretical field of fatigue strength of a multi-axis thermal engine, and in particular relates to a stress-strain calculation method of a dangerous point of a high-temperature structure. Background technique [0002] In engineering service, there are a large number of gaps in some main parts of various aerospace vehicles, pressure vessels, nuclear power plants and power plants, and the actual structure will inevitably have defects due to various reasons during processing and use. These gaps or A defect is a dangerous point of a structure. Under variable temperature and complex alternating loads, these dangerous points will be in a complex local multiaxial fatigue stress-strain state, resulting in multiaxial fatigue failure of components. Therefore, in order to prevent sudden fatigue failure and ensure the safe and reliable operation of the mechanical structure, it is necessary to design the fatigue strength of the dangero...

AI Technical Summary

Problems solved by technology

Among them, the test method is too expensive for some complex components, and it is not easy to measure the strain of mechanical components under high temperature or high speed rotation

The finite element analysis (FEA) method can perform elastic-plastic analysis to a certain extent, but when analyzing complex components, the calculation amount is huge, the analysis cost is high, and the stress-strain response of components cannot be quickly described

Images