Investigation of plastic zone development in dynamic tear test specimens

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Authors
  1. Koko, T.S.
  2. Gallant, B.K.
  3. Matthews, J.R.
Corporate Authors
MARTEC Ltd, Halifax NS (CAN);Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
This paper presents on-going investigations on plastic zone development in dynamic tear (DT) type three-point bend specimens used to measure the fracture toughness of marine structural materials. The purpose of the study is to use finite element technology to provide an understanding of the plastic zone development, to determine the upper limit of temperature relative to full size transition curves where elastic plastic fracture becomes invalid. In earlier studies, the authors utilized 2-D finite element models to compute the ratio of crack tip blunting (stretch zone) to plastic zone size (radius) that is used to determine the elastic-plastic fracture toughness. Those studies established the feasibility, as well as limitations, of 2-D finite element modeling for computing the plastic zone development in DT specimens. In the present study we present efforts geared towards improving the 2-D modeling, as well as investigations into the use of 3-D models to provide estimates of the shear lip size. The ABAQUS finite element software was used to model the elastic-plastic behavior of the specimens. The DT specimen was made of 350WT steel and the crack was induced by pressing the notch, followed by fatigue cracking at a limit load level of 40% of the specimen limit load. The specimen was loaded until fixed amounts of permanent deformation were recorded. TRUNCATED
Keywords
Dynamic Tear Transition Curve;Fracture transition;350WT steel;Elastic Plastic Fracture Toughness;Plastic Zone Radius
Report Number
DREA-SR-2001-094-SES-IX-PAP-46 — Special Report
Date of publication
01 Oct 2001
Number of Pages
15
DSTKIM No
CA011883
CANDIS No
516461
Format(s):
Hardcopy;Document Image stored on Optical Disk

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