切欠き領域にある疲労き裂の弾塑性破壊力学に基づく評価
切欠き材における疲労き裂の初期伝播特性(第2報)
1987 年 5 巻 4 号 p. 544-550
詳細
1987 年 5 巻 4 号 p. 544-550
In order to assess the growth rates of initial cracks in inelastic notch fields by cyclic loads, it is inevitable to apply clasto-plastic fracture mechanics. In the present report, the evaluating method of ΔJ was developed for the initial fatigue cracks in the inelastic notch fields. The interpolation function for calculation of J-integral by Willson was modified for application to the notch fields. In the calculation of J-integral stress gradient was considered in the notch fields without cracks.
Fully reversed fatigue tests were carried out on the notched strips of HT80 and A5083-O. The crack closure behaviors in the notch fields were observed. The approximating equations were formed to predict crack opening ratios in the notch fields. The fatigue crack growth rates in the notch fields were plotted to ΔJ. As the results, it was cleared that the present ΔJ is applicable to assess the fatigue cracks in both the elastic and inelastic notch fields. And then, the phisical meaning of ΔJ was discussed.
