Accession Number : AD0663884

Title :   EFFECT OF SIDE GROOVES AND FATIGUE CRACK LENGTH ON PLANE-STRAIN FRACTURE TOUGHNESS.

Descriptive Note : Interim rept.,

Corporate Author : NAVAL RESEARCH LAB WASHINGTON D C

Personal Author(s) : Freed,C. N.

Report Date : 07 DEC 1967

Pagination or Media Count : 20

Abstract : An investigation was made to determine the effect of side grooving on plane-strain fracture toughness K sub Ic values obtained with smooth single-edge-notched tension specimens. In most cases the smooth and side-grooved values differed by only plus or minus 1 to plus or minus 3% for high strength steels and alloys of titanium and aluminum. The side-grooved specimens tended to slightly underestimate K sub Ic. Side grooves accentuate the displacement due to crack instability on the load-displacement record and permit K sub Ic values to be computed for specimens in which detection of crack initiation could not otherwise be made. The specimen is likely to fracture at or near maximum load when side grooves are employed. For the specimen geometry used in this investigation it has been determined that fatigue cracks of 0.05 in. and less in length cause the K sub Ic values for side-grooved specimens to be overestimated. There seems to be no relationship between the length of the crack, below 0.05 in., and the amount by which K sub Ic is increased. (Author)

Descriptors :   (*STEEL, FRACTURE(MECHANICS)), (*ALUMINUM ALLOYS, FRACTURE(MECHANICS)), (*TITANIUM ALLOYS, FRACTURE(MECHANICS)), TOUGHNESS, CRACKS, FATIGUE(MECHANICS), DEFECTS(MATERIALS), STRESSES, STRAIN(MECHANICS)

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE