中文摘要：

应用单试样规则化法完成了压力容器用钢SA-508紧凑拉伸（Compact tension,CT）、三点弯曲（Single edge-notched bending,SEB）和小尺寸含内侧边裂纹C形拉伸（C-shaped inside edge-notched tension,CIET）三类试样的延性裂纹扩展行为试验,获得了J-Δa阻力曲线.结果表明,SA-508钢的J-Δa阻力曲线受试样构形和裂纹尺寸的影响较大,其根本原因在于试样裂纹尖端约束不同而引起延性断裂行为差异.引入J-Q-M三参数约束理论考察断裂试样的裂尖约束效应,采用权重平均法求解与距离无关的约束参数Q.弹塑性有限元分析结果表明,平面应变条件下的Q参数与载荷水平无关,但三维条件下的Q参数却仍受载荷水平的影响.基于J-Q-M三参数约束方法,建立三类试样满足J-Q-M控制的有效尺寸条件.进一步地,结合条件启裂韧度J0.2BL、J0.5BL试验结果和J-Q-M理论,获得了基于Q参数的约束修正J-Δa阻力曲线簇,可用于任意约束试样以及实际含裂纹结构的延性断裂行为预测.

英文摘要：

Experiments on compact tension（CT）, single edge-notched bending（SEB） and C-shaped inside edge-notched tension（CIET） specimens for pressure vessel steel SA-508 by using normalization method are carried out. The resultedJ-Δacurves are affected by specimen configurations and crack sizes, which is essentially owing to the different crack front constraint effect of specimen.J-Q-M three-parameter theory is introduced to qualify the crack front constraint effect, and weight average method is applied to solve the distance-independent constraint parameterQ. Finite element analyses show that, the parameterQ is load-independent under plane strain condition, but it is still influenced by load level under 3D condition. The size requirements ofJ-Q-Mdominance for three types of specimens have been constructed. Furthermore, by combining the experimental conditional critical toughnessesJ0.2BL,J0.5BL and J-Q-Mapproach, the constraint-correctedJ-resistance curves are established based on the parameterQ, these curves can be applied to predict the ductile fracture behavior for any specimen and actual flawed structures.