Mechanical structure fuzzy fatigue reliability optimization method based on self-constructed membership function

Abstract

The invention discloses a mechanical structure fuzzy fatigue reliability optimization method based on a self-constructed membership function, and belongs to the field of fatigue reliability optimization. The objective of the invention is to solve the problem of fuzzy fatigue reliability optimization design under a small amount of sample data. The principle includes: representing fatigue damage fuzziness of a mechanical structure by a self-constructed membership function, verifying the accuracy of the mechanical structure through test data, and deriving a failure probability and reliability analysis expression; defining a random variable, a fuzzy variable and a fuzzy fatigue reliability function, verifying the accuracy of the function, and establishing an optimized objective function; and determining a design variable constraint condition, determining an optimization target interval based on a blind number theory, performing global optimization through a genetic algorithm, and obtainingan optimal result. The uncertainty factors of the size, material parameters and load of the mechanical structure are fully considered, the fatigue damage fuzziness of the mechanical structure is represented through the self-constructed membership function, the optimization target interval is defined based on the blind number theory, calculation is accurate and reliable, and the efficiency is high.

Description

technical field [0001] The invention relates to a method for optimizing the fuzzy fatigue reliability of a mechanical structure based on a self-constructed membership function, and belongs to the field of fuzzy fatigue reliability optimization. Background technique [0002] When calculating the fatigue reliability of structural parts based on the traditional linear cumulative damage theory, the damage caused by the stress higher than the fatigue limit is always considered, and the damage lower than the fatigue limit is ignored. In fact, below the fatigue limit, there is ambiguity about whether the stress will cause damage to the component, that is to say, under certain conditions, the stress level below the fatigue limit will also cause fatigue damage. Therefore, compared with the traditional linear cumulative damage theory, it is more effective to explore structural fatigue reliability based on fuzzy theory. [0003] With the increasingly harsh service environment of mecha...

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Problems solved by technology

[0004] In order to solve the problems of low prediction accuracy and calculation efficiency in the existing mechanical structure fuzzy fatigue reliability optimization method, and to overcome the defects described in the background technology, the present invention provides A method for optimizing fuzzy fatigue reliability of mechanical structures based on self-constructed membership functions, the method of the present invention includes the following steps:

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