第1部分:CTOD断裂韧性试验的工程方面对四种压力容器钢和一种船舶钢的裂纹尖端张开位移（CTOD）断裂行为进行了研究。调查的目的是确定钢的断裂行为，研究CTOD试验变量的影响，检查评估试验记录的各种方法，并研究几种断裂韧性参数之间的关系。所研究的五种钢（A508、A533、A516、A517和A131）的屈服强度在240 MPa到750 MPa之间。此外，还研究了A533和A516钢的三种试样尺寸。第2部分:三点弯曲试样几何形状的三维弹塑性有限元分析作为研究裂纹尖端张开位移（CTOD）断裂参数在有缺陷压力容器中的应用的一部分，对三点弯曲试样几何形状进行了弹塑性有限元分析。 根据二维和三维有限元分析结果确定了弹塑性断裂力学（E-PFM）参数CTOD和J积分。考虑了三种尺寸的首选试样几何形状（厚度、t、深度、2t、跨度、8t）和五种具有不同应力应变特性的钢材。为了获得用于比较的试验结果，根据BS 5762:1979“裂纹张开位移试验方法”中概述的程序进行试验第3部分:使用CTOD方法的缺口压力容器失效预测目前公认的确定缺口容器失效压力的分析程序仅限于由线弹性断裂力学（LEFM）或极限载荷计算定义的行为类型。LEFM仅限于非常脆性的材料行为（ASTM E-399定义的线弹性平面应变行为，KIc）。 极限载荷计算仅限于上层架、与流动应力相关的材料行为。这两种分析之间存在广泛的材料行为，应使用弹塑性断裂力学（E-PFM）分析。

Part 1: Engineering Aspects of CTOD Fracture Toughness TestingAn investigation of the Crack Tip Opening Displacement (CTOD) fracture behavior of four pressure vessel steels and one ship steel has been conducted. The purpose of the investigation was to determine the fracture behavior of the steels, to study the effects of CTOD testing variables, to examine various methods of evaluating test records, and to study the relationships among several fracture toughness parameters. The five steels studied (A508, A533, A516, A517, and A131) had yield strengths from 240 MPa to 750 MPa. In addition, three specimen sizes of the A533 and A516 steels were studied.Part 2: Three-Dimensional Elastic-Plastic Finite Element Analysis of Three-Point Bend SpecimenElastic-plastic finite element analyses of the three-point bend specimen geometry were performed as part of an investigation to study the application of the Crack Tip Opening Displacement (CTOD) fracture parameter to flawed pressure vessels. The Elastic-Plastic Fracture Mechanics (E-PFM) parameters, CTOD and J-Integral, were determined from the results of 2-D and 3-D finite element analyses. Three sizes of the preferred specimen geometry (thickness, t, by depth, 2t, by span, 8t) and five steels with varying stress-strain characteristics were considered. To obtain experimental results for comparison, tests were conducted according to the procedure outlined in BS 5762:1979 "Methods for Crack Opening Displacement Testing."Part 3: Failure Prediction of Notched Pressure Vessels Using The CTOD ApproachCurrently accepted analysis procedures to determine failure pressures of notched vessels are limited to the types of behavior defined by Linear Elastic Fracture Mechanics (LEFM) or by limit load calculations. LEFM is restricted to very brittle material behavior (linear elastic plane-strain behavior, KIc, as defined by ASTM E-399). Limit load calculations are restricted to upper shelf, flow stress dependent material behavior. There is a wide range of material behavior between these two types of analysis where Elastic-Plastic Fracture Mechanics (E-PFM) analysis should be used.