J-RESISTANCE CURVE OF HY100

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Authors
  1. Faucher, B.
  2. KarisAllen, K.
Corporate Authors
Metals Technology Labs, Ottawa ONT (CAN);Defence Research Establishment Atlantic, Dartmouth NS (CAN)
Abstract
A precise knowledge of toughness of materials is needed to evaluate the fitness-for-purpose of structures with defects. For brittle materials as steels at low temperature, the toughness is measured with the stress intensity factor, K. Steels at high temperature are tough and their toughness is then measured either with the CTOD (Crack tip opening displacement) or the J-integral. These quantites are related as: J = K2/E = sigma y (CTOD) were E and sigma y are material's Young's modulus and yield strength, respectively. Increasing resistance of material to crack advance during tearing is taken into account by the J-resistance curve. It is a graph of J as a function of crack extension. J is obtained from experimental load-deformation curve, and crack extension from different techniques to monitor crack length during the test; the most common one, standardized by ASTM, is the unloading technique which requires to stop the test for a short period of time to measure the compliance of the specimen at regular intervals. This technique is delicate of application, time consuming and, of course, not applicable to impact testing. An alternative method to obtain the crack length is by comparing the experimental load-displacement curve to a reference curve, the "key-curve", obtained for a specimen with no crack extension. TRUNCATED
Report Number
DREA-NAMT-93-2-PAP-5 — CONTAINED IN 99-00578
Date of publication
30 Apr 1993
Number of Pages
20
DSTKIM No
99-00583
CANDIS No
510310
Format(s):
Hardcopy;Document Image stored on Optical Disk

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