【摘要】 <正> 最近几年,国内外对疲劳裂纹起始超载效应的研究尚未能给出长寿命范围内超载对疲劳裂纹起始寿命影响的定量表达式:个别研究给出了短寿命范围内超载对疲劳裂纹起始寿命影响的表达式。更多还原

【Abstract】 In the puesent shudy the efficte of overloading and overloading ratios on fatigue crack initiation life(FCIL)of LY12CZ alloy sheets are expcritnentally investigated by using notched specimens and the test results, are well fitted by the formnla recently developed for FCIL,Test results show that tension overloading ineeases the threshold for FCTL but has no remarkable effect on the coefficient of the resistance to FCIL. The overloading ratio defined in this paper has no remarkable effect on FOIL and FCILthreshold of LY12CZ sheets after tension orerloading.The increas-ed FCIL threshold by tension overloading results in the increase of FCIL, particularly, in long life ranges更多还原