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。
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.
作者
包陈
蔡力勋
但晨
何广伟
BAO Chen CAI Lixun DAN Chen HE Guangwei(School of Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031 Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province, Southwest Jiaotong University, Chengdu 610031)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2017年第2期34-44,共11页
Journal of Mechanical Engineering
基金
国家自然科学基金资助项目(11202174
11472228)
