Part 1: Engineering Aspects of CTOD Fracture Toughness Testing
An 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 Specimen
Elastic-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 Approach
Currently 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.
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| Number of Pages : | 41 |
| Published : | 1984 |
