【摘要】 进行了循环载荷的缺口顶端局部应变和形变功密度的循环J 积分分析和实验标定,证实:缺口顶端形变功密度依赖于循环J 积分和缺口半径ρ之比,即:△J/ρ=α_c△W₀通过对缺口疲劳裂纹形成过程的分析,并依据上述关系和光滑试样应变疲劳关系N_?（△W）^?=c,提出了予测缺口疲劳裂纹形成寿命的公式:N_i（△J/α_cρ）^β=c_n进行了各种缺口试样,在各种载荷条件的疲劳裂纹形成实验,结果证明,对不同应力比R 的载荷,在各种形变程度:从线弹性至全面屈服,疲劳裂纹形成寿命N_i 和△J/α_cρ均满足此关系式.分析比较了△J/α_cρ和缺口疲劳领域的另两个常用参量△K/ρ^1/2和1/2△ε之间的关系,△J/α_cρ较后两者有更广泛的适用性.更多还原

【Abstract】 The cyclic J-integral analysis and experimental calibration of local strain and deformation work density at notch root of notched fatigue specimens show that the deforma- tion work density at the notch tip is related to the ratio of applied J-integral to the no-tch radius ρ,i.e.△J/ρ=α_c△W₀.Based on this formula and the life relationship N_f（△W）（?）=C for the strain fatigue ofsmooth specimens,the following fatigue crack initiation life formula for notched speci-mens is proposed:N_i（△J/α_cρ）^β=C_?Fatigue crack initiation experiments conducted on notched specimens of different ge-ometries and loading conditions show that the above notch fatigue crack initiation for-mula is valid in avery wide range of loading conditions:from small-scale yielding to gen-eral yielding with different stress ratios R.Having analyzed the new parameter △J/α_cρ and compared it with other parameters△K/ρ^1/2and △1/2εoften used in the field of notch fatigue,it is concluded that the newparameter △J/α_cρ is ore reasonable and useful than the others for analysis of notchfatigue crack initiation.更多还原