不規則進展抵抗をもつ疲労き裂進展の確率論的考察
1986 年 35 巻 391 号 p. 414-420
詳細
1986 年 35 巻 391 号 p. 414-420
A stochastic approach to fatigue crack propagation is proposed in consideration of random propagation resistence. It is based on the Paris-Erdogan's propagation law of fatigue crack. By adding the Gaussian white noise to propagation resistance of the propagation law, a non-linear Langevin equation is obtained. A stochastic differential equation of Ito type is derived from the Langevin equation by using a change of variable in the equation and Wong and Zakai's theorem. By using the solution of the stochastic differential equation and its probability density, a sample path and life distribution of fatigue crack propagation are derived, respectively. These theoretical results are compared with the experimental data for high tensile strength steel APFH 60. Through the comparison, an improvement in the above approach is made.
