预估构件裂纹扩展寿命的封闭解法及其在起落架中之应用

本文以Matsuoka模型为基础,以航空上常见的短周期加载为条件,导出了预估构件的裂纹扩展寿命的解析表达式 式中,α、β和γ分别为裂纹扩展速率Walker公式的系数与指数,n=β+γ,p是每一个加载周期中的程序块数,N_i为第i个程序块中加载次数,Z（α）是应力强度因于的几何因子。 我们采用本方法对某机前起落架剩余寿命试验的破坏部位寿命进行了预估,试验表明:计算结果比试验结果低18％。

CLOSE FORM SOLUTION FOR PREDICTION OF CRACK PROPAGATION LIFE OF STRUCTURE MEMBER AND ITS APPLICATION TO LANDING GEARS

In this paper,according to Matsuoka's retardation model,under the condition of short period loading,a close form solution for crack propagation life/of structure ,member is derived as followswhere,a,B and r are coefficients and exponents of Walker's formula for crack propagation rate, n =B + y,p is the number of program blocks per loading period, Ni is the frequency of loading of i-th program block,Z（a） is the geometric factor of stress intensity factorThis method was used to predict the residual life about failure position of nose landing gear for certain type of fighters.Test showed that the computational result is lower than the mean value of experimental ones by 18% only.