Investigation of Plastic Zone Development in Dynamic Tear Test Specimens

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Authors
  1. Koko, T.S.
  2. Matthews, J.R.
  3. Hyatt, C.V.
  4. Roy, V.
Corporate Authors
MARTEC Ltd, Halifax NS (CAN);Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
The J-integral is an elastic-plastic fracture criterion, which permits measurement of the fracture toughness of a specimen that has been fractured after general yielding. An understanding of the ratio of plastic zone size (radius) to the crack tip blunting (stretch zone) is required to determine the upper limit of temperature relative to full size transition curves where elastic plastic fracture becomes invalid. This study endeavours to acquire this ratio using finite element techniques. The development of the plastic zone in dynamic tear (DT) specimens and a non-standard three point bending fracture test specimen used to measure fracture properties was the main focus of the study. The ABAQUS finite element software was used to model the elastic-plastic behaviour of the specimens. For the DT specimen a crack was induced by pressing the notch, followed by fatigue cracking at a limit load level of 40% of the specimen limit load, whereas, the crack shpae for the non-standard specimen was a fatigue crack defined at approximately 30% of the limit load. The shapes of these cracks were adequately modelled in the finite element analysis. The specimens were made of 350WT steel and 304 stainless steel materials and were loaded until fixed amounts of permanent deformation were recorded. TRUNCATED
Report Number
DREA-SR-1999-162-PAP-7 — CONTAINED IN CA000150
Date of publication
01 Oct 1999
Number of Pages
29
DSTKIM No
CA000157
CANDIS No
511881
Format(s):
Hardcopy;Document Image stored on Optical Disk

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