【摘要】 寻求疲劳裂纹长度a与疲劳周次N的关系式是金属疲劳研究的一个重要课题。本文提出了a与N的近似关系式,即指数一多项式样条函数关系式a=β₁e^γx+sum from j=2 to k β_j（x-x₂）（j-2）)₊³,其中x=10^-3。N,k=[（m+3）/2]。用计算机仿真的方法确定了γ的最佳值。由上式导出了计算da/dN的如下近似公式: （da）/（dN）=10^-3[β₁γe^γx+3 sum from j=2 to k β_j（x-x₂（j-2））₊²]与Mc Cartney关系式进行了对比,结果表明,拟合实验数据时前式的适用性优于Mc Cartney关系式;计算da/dN时后式的可靠性优于Mc Cartney关系式。更多还原

【Abstract】 It is an important subject of metal fatigue research to find out the formula of fatigue crack length a and cycles N. An approximate formula of a and N is proposed in this paper. It is an exponential-polynomial spline function:α=β₁^eγx+（sum from j=2 to k）β_j(x-x₂（j-2）₊⁸, where x=10^-3. Nk= [（m+3）/2]. The optimum Value of γ is determined by the method of computer simulation. From the formula an approximate formula for computing da/dN is derived as follows:da/dN=10^-3[β₁^γeγx+ 3（sum from j=2 to k）β_j(x-x₂（j-2）₊²].In comparison with McCartney formula, it is shown that former formula is better than McCartney formula in adequacy for fitting experimental data, and latter formula is better than McCartney formula in reliability for computing da/dN.更多还原