【摘要】 本文采用和的混合线性硬化材料塑性本构关系,求得了平面应变与平面应力状态下Ⅰ型定常扩展裂纹尖端附近场的渐近解。Amazigo和Hutchinson的结果相当于本文解当混合硬化参数β=1且略去二次塑性区的情况。本文的数值计算结果表明,混合硬化参数β对尖端场的应力应变分布有着显著的影响。更多还原

【Abstract】 Based on the constitutive law for mixed linear hardening suggested by Kadaschevich and Novozhilov, the asymptotic solution are obtained for the near-tip fields for mode-I crack during steady growth in plane-strain and in plane-stress state. A mixed hardening parameter β is introduced, with the extreme values β = 1 for isotropic hardening and β = 0 for kinematic hardening. Numerical results are obtained for various values of tangent modulus ratio α= Et/E and parameter β.For plane-strain problem (with Poisson’s ratio v = 1/3), the order of singularity s and angles θP, θs subtended by plastic zones are shown in Table 1. Forα = 0.01, β = 1,0.5, the angular distribution curves of equivalent active stress, stress components and plastic strain-rate components are shown in Figs. 3-5. In the same figures are also shown the results of Amazigo and Hutchinson, who neglected the secondary plastic zone. Comparison shows that for materials with low hardening (e. g. a = 0.01) the secondary plastic zone plays a significant role.For plane-stress problem, values of s, θp and θs are shown in Tables 2,3 and 4, respectively. Again forα= 0.01, β= 1, 0.5, 0.1, the angular distribution curves of stresses are shown in Figs.7 and 8, and those of plastic strain-rates in Fig. 9.All the numerical results show that the anisotropy of hardening is an unnegligible factor in the consideration of crack-tip fields.更多还原