平面裂纹的起裂准则

The Initiation Criteria of the Two Dimension Crack

针对著名断裂教授 sin 提出的著名[S]min准则中所存在的若干缺陷,作者曾利用宏微观相结合的方法在文献[1,2]中提出了三个三维裂纹的起裂准则并很成功地解决了三维表面裂纹问题。本文的主要贡献在于:1 针对平面裂纹的特殊个性,对文献[1,2]的假定作了更符合实际的改变,提出了二维裂纹的[Uv]max、[σα]max和[γp]min准则。2 推出了平面裂纹起裂角和载荷的一般方程。3 求出了Ⅰ型和Ⅱ型裂纹的起裂角θ*和相应的 KⅢc/KⅠc值,这些值和实验结果比较表明本文所提准则较其它准则更佳。4 讨论了 Possion（泊松）比 v 和应力状态对θ*和 KⅡc/KⅠc值的影响,得出了 v 和应力状态对θ*几乎无影响而对 KⅡc/KⅠc有较大影响这一令人满意和从未有过的新发现。给出了三准则适用条件。

Directing at the defects of the famous [S]_(min) criterion proposed by famous professor G.C.Sih,we have suggested three criteria of the three dimension crack in refs.[1,2] with the help of the combination of the micro-theory and macro-theory and have successfully solved the three dimension surface crack problems.The main contributions of this paper are as follows: (1)For the two dimension crack,it is possible to go beyond the general three dimension criteria.Some practicable changes on the assumptions in refs. [1,2] are taken,and the criteria [U_v]_(max),[σ_a]_(max) and [r_p]_(min) are suggested for two dimension crack problems. (2) The general equations of the initial angle θ~* and the non-dimensional load parameter K_(kc)/K_(Ic) for the two dimension crack problems are given. (3)The values of the initial angle θ~* and K_(kc)/K_(Ic) in model Ⅰ and model Ⅱ crack problems,which are obtained from the general equations,agree with the experimental data better than those of other criteria. (4) The discussion of the influences of the Poisson constant μ and stress state on the angle θ~* and K_(kc)/K_(Ic),show that the value of μ and stress state have little influence on the angle but great influence on K_(kc)/K_(Ic).