SEDL / STP / STP590-EB / STP33937S

Single Specimen Tests for J^Ic Determination

Clarke, GA
Stress analysis engineer and materials test engineer, General Electric Company, Schenectady, N. Y.

Andrews, WR
Stress analysis engineer and materials test engineer, General Electric Company, Schenectady, N. Y.

Paris, PC
Chairman and chief executive officervisiting professor of engineering, Del Research CorporationBrown University, HellertownProvidence, Pa.R. I.

Schmidt, DW
Engineer, Del Research Corporation, Hellertown, Pa.

Pages: 16    Published: Jan 1976

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Abstract

A J^Ic test procedure using a single deeply cracked specimen is proposed. The crack extension is measured by partially unloading the specimen to determine the elastic compliance. J^Ic tests were made using ASTM A469 steel. Compact specimens from 1/2T to 5T were tested. No size effect was found. Results from two independent laboratories are presented and are in agreement. The errors due to simple formulation of J^I calculation, periodic partial unloading, and simplified analysis for the extension of deep cracks in compact specimens are explored. The measurement point of crack extension for establishing J^Ic is discussed. The results indicate that a practical and effective single specimen test procedure has been developed.