Fatigue life prediction method of tension-torsion thermomechanical system based on damage mechanism

Abstract

The invention discloses a tensile-torsional thermomechanical fatigue life prediction method based on a damage mechanism, which relates to the multiaxial thermomechanical fatigue strength theory field.The algorithm steps are as follows: (1) according to the damage mechanism under the tensile-torsional thermomechanical fatigue loading, the total damage is accumulated by fatigue damage, creep damageand oxidation damage; (2) calculating fatigue damage; (3) calculating creep damage; (4) calculating oxidative damage; (5) calculating the total damage and obtain the fatigue life under tension-torsion thermomechanical loading. In order to verify the effect of the present invention, the predicted results obtained by the present method are compared with the results of a tensile-torsional thermomechanical fatigue test. The test results show that the difference between the predicted fatigue life and the test results is less than 2 times of the factor. Therefore, the proposed method can be used topredict the fatigue life under tension-torsion thermomechanical loading.

Description

Technical field [0001] The invention belongs to the field of multiaxial thermomechanical fatigue strength theory, and particularly relates to a method for predicting fatigue life of tensile and torsion thermomechanical fatigue based on a damage mechanism. Background technique [0002] The key components of aero engines, gas turbines, hypersonic critical space vehicles, pressure vessels, nuclear power plants, power plants, and daily vehicles are often in service under severe high-temperature thermo-mechanical coupling loading environments, and these equipment have very high requirements for safe service. high. If an accident caused by fatigue failure occurs, it will cause personal injury accidents and significant economic losses. During the start, stop, and other rapid operation of the above major equipment, the interaction of the hot end parts subjected to the multi-axis compound cyclic load under high temperature and temperature change can be called multi-axis thermo-mechanical...

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Problems solved by technology

[0003] Since the strength design using the fatigue strength theory at room temperature or high temperature and constant temperature cannot meet the requirements of the strength and life design of parts such as aero-engines, there is an urgent need for a life prediction method that can be applied to multi-axial thermomechanical fatigue loading. Improve the reliability of the strength design of hot-end parts of aerospace, military equipment and other products

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