強さ(パワ)の異なるガウス性ランダム荷重の重複負荷下における疲労寿命の推定

概要

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This paper presents a method for estimating the fatigue life of S40C steel, with or without a notch, under multiple Gaussian random loadings. First, a random S-N curve for a simple Gaussian random load is so proposed theoretically that the cumulative damage Σ(n/N) calculated from the curve equals unity, with the aid of the frequency of peak stress representing an approximate Rayleigh distribution. The curve is of the form : N_fσ^<m'> = C'Γ(1 + m/2) , where m, m' and C' are material constants and Γ(x) represents a gamma function. Second, an attempt is made to estimate the fatigue life under multiple Gaussian random loads applied to the material over its whole life. It is found that the cumulative damage is given by the sum of the cumulative damage of each component Gaussian random load, and that fatigue life can be easily estimated by using the aforementioned S-N curve. This implies that the random S-N curve proposed is very useful for fatigue life estimation under random loading.
社団法人日本材料学会の論文
1975-05-15