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介绍了应用Levenberg-M arquardt迭代法计算局部应力和局部应变的工作。Levenberg-M arquardt迭代法是求解超越方程的一种常用数学方法,但是缺点是程序比较复杂,计算效率较低,因此本文目的是找到一种程序实现简单、计算效率高、计算精度满足要求的计算方法,选择了二分法,并且对比分析了二分法和Levenberg-M arquardt迭代法求解局部应变与应变寿命方程的效率和精度,从而得出应用二分法来进行求解是简单并且可以被工程应用的;最后结合某飞机结构一种带孔部件的实例,应用局部应力应变法给出了该部位的寿命预测值,通过和试验寿命值的对比,得出了考虑平均应力修正的应变寿命方程才更符合工程要求。
The application of Levenberg-M arquardt iterative method to calculate local stress and local strain is introduced. Levenberg-M arquardt iterative method is a common mathematical method to solve the transcendental equation, but the disadvantage is that the program is complicated and computational efficiency is low. Therefore, the purpose of this paper is to find a method to calculate the transcendental equation with simple calculation, high computational efficiency, Method, the dichotomy is selected, and the efficiency and accuracy of the dichotomy and the Levenberg-M arquardt iterative method for solving the local strain and strain life equations are contrasted and analyzed. It is concluded that the dichotomy is simple and can be applied in engineering. Finally, with the example of a kind of perforated part of an aircraft structure, the local stress-strain method is used to predict the life expectancy of the part. By comparing with the test life value, it is concluded that the strain life equation considering the average stress correction is more consistent Engineering requirements.