Crack propagation

In view of improvement of the fitting effect of the threshold area and Paris area and further utility of the testing information, the Paris formula is revised, the crack spreading rate curve is developed reasonably to the fast spreading area, so as to obtain the complete fatigue crack spreading rate curve which can reflect the crack spreading patterns of the material in different areas.

從改進近門檻區與Paris區擬合效果和進一步利用試驗信息的角度,對Paris公式進行了修正,合理地延拓裂紋擴展率曲線到快速擴展區,進而得到能夠反映材料在不同區域裂紋擴展規律的完整疲勞裂紋擴展率曲線,并通過16MnR鋼的試驗數據分析和PW—200型客車轉向架關鍵部位的裂紋擴展壽命估算進行了驗證。