选用统一拘束参数A_p，采用有限元模拟方法分别对不同初始裂纹尺寸下管道结构和实验室单边缺口弯曲（SENB）试样、紧凑拉伸（CT）试样、单边裂纹拉伸（SENT）试样和中心裂纹拉伸（CCT）试样的裂尖拘束度进行了表征，并构建了管道结构与实验室试样间裂尖拘束度的匹配。结果表明：管道结构的裂尖拘束度与SENB试样和CCT试样的裂尖拘束度匹配性较差；初始裂纹尺寸a/c=0.2，a/t=0.5（a为裂纹深度，c为1/2裂纹长度，t为管壁厚度）条件下管道结构的裂尖拘束度与含有深裂纹（a/W=0.7，W为试样宽度）CT试样的裂尖拘束度相接近，初始裂纹尺寸a/c=0.8，a/t=0.5，0.8条件下管道结构的裂尖拘束度与含有深裂纹（a/W=0.5，0.6，0.7）CT试样的裂尖拘束度相匹配；管道结构的裂尖拘束度与SENT试样的裂尖拘束度相近，二者具有较好的匹配性；在对实际结构进行完整性评定时，可选择与实际结构裂尖拘束度相近的实验室试样进行断裂力学试验，以其测定的断裂力学性能对该实际结构进行评定，从而增加评定的准确性。

Crack-tip constraints of pipe structures and laboratory single edge-notched bend (SENB) specimen, compact tension (CT) specimen, single edge-notched tensile (SENT) specimen and centre-cracked tension (CCT) specimen with different dimensions of initial cracks were characterized by finite element simulation method using the unified constraint parameter A_p, and the matching of crack-tip constraints between pipe structures and laboratory specimens were built. The results show that the matching of crack-tip constraints between pipe structures and SENB specimens, CCT specimens was poor. The crack-tip constraint of pipe structure with a/c=0.2, a/t=0.5 (a representing deep of crack, c representing half length of crack, t representing wall thickness of pipe) was similar to that of the CT specimen with deep cracks (a/W=0.7, W representing width of specimen); the crack-tip constraint of pipe structure with a/c=0.8, a/t=0.5, 0.8 was similar to that of the CT specimen with deep cracks (a/W=0.5,0.6 and 0.7). The crack-tip constraint of pipe structures was similar to that of SENT specimens, their crack-tip constraints matched very well. During the integrity assessment of actual structures, the laboratory specimen with the similar constraint to actual strcutre could be selected to carry out fracture mechanical experiments, and the assessment accuracy could be improved when the actual structure was assessed by the measured fracture mechanical properties.