Accession Number : AD0256118

Title :   METHOD OF EVALUATING THE SENSITIVITY OF MATERIALS TO CRACKS

Corporate Author : FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO

Personal Author(s) : DROZDOVSKIY,B.A. ; FRIDMAN,YA.B.

Report Date : 03 NOV 1960

Pagination or Media Count : 1

Abstract : Static bend tests are conducted on specimens of different materials notched with a crack previously obtained by repeated impact loading. In materials with high tensile strength, the sensitivity to cracks can be particularly high and change very greatly from melt to melt. The testing of cracked specimens is particularly advisable, especially since evaluation of the sensitivity to cracks according to the magnitude of the work of fracture of the notched specimen is difficult, particularly for many high-strength materials. In a material sensitive to cracks (low-tempered steel) in a given specimen shape, there is a definite depth of the crack (in current tests less than 0.2 mm) conducive to a sharp reduction of the breaking load during bending. The different methods used to obtain cracks give practically the same values for the fracture stress if the sharpness of the crack, and especially its directions, are the same in relation to the greatest normal stresses during bending. Of the methods used to obtain cracks, (single loading, cyclic impact loading, cathode-hydrogen cracking), the one that best reproduces cracks of a given size is cyclic loading. (Author)

Descriptors :   *FRACTURE (MECHANICS), *MATERIALS, *STEEL, ALLOYS, DEFORMATION, ENZYMES, FAILURE (MECHANICS), IMPACT SHOCK, MECHANICAL PROPERTIES, METALS, SENSITIVITY, STRESSES, TEST EQUIPMENT, TEST METHODS

Distribution Statement : APPROVED FOR PUBLIC RELEASE