Topological optimization method for multi-load fatigue life constraints

Abstract

The invention relates to a topological optimization method for multi-load fatigue life constraint, which comprises the following steps of: obtaining a structure dangerous point position and extractinga stress time history by a finite element method aiming at a random vibration load borne by a component; counting the stress time history through a rain flow counting method, sorting the stress timehistory according to amplitudes, and segmenting the stress time history in a variable interval manner; according to a fatigue damage equivalence principle, adopting a Miner linear cumulative damage method to perform damage equivalent conversion, and the load cycles in the interval are combined into one load cycle; then, based on the linear damage accumulation criterion and the multi-axis fatigue analysis principle, reversely calculating the maximum stress level enabling the component to be subjected to fatigue failure according to the design life requirement of the component, and obtaining theoptimal structure of the component by taking the stress level as the constraint condition of topological optimization. According to the method, the fatigue life constraint under the complex random load can be efficiently converted into the stress constraint, so that the lightweight design of the structure is achieved while the fatigue strength is met, and engineering application is facilitated.

Description

technical field [0001] The invention relates to a topology optimization method with multi-load fatigue life constraints, belonging to the technical field of structural lightweight design. Background technique [0002] The purpose of structural optimization is to improve the performance of the structure. Under the premise of meeting the design requirements, the material can be optimally distributed by changing the topological form and size of the structure. Topology optimization is widely used in aviation, aerospace, automobiles and other fields, making the structure lighter and lighter, and its performance continuously improved. At present, a large number of studies have been carried out on topology optimization under the constraints of displacement, stiffness, strength, frequency, volume, and mass in engineering practice. When the allowable stress is selected as the stress constraint in topology optimization, the value of the safety factor will vary due to different design...

AI Technical Summary

Problems solved by technology

When the allowable stress is selected as the stress constraint in topology optimization, the value of the safety factor will vary due to different designers, which will affect the lightweight results; under the action of actual cyclic loads, the work that causes fatigue failure of the mechanical structure Stresses are often lower than the calculated allowable stress values

As a result, the optimization results often do not meet the fatigue strength requirements

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