Accession Number : AD0695657

Title :   EXPERIMENTAL AND ANALYTICAL STRAINS IN AN EDGE-CRACKED SHEET.

Descriptive Note : Technical rept.,

Corporate Author : WATERVLIET ARSENAL N Y BENET R AND E LABS

Personal Author(s) : Underwood,John H. ; Swedlow,J. L. ; Kendall,David P.

Report Date : SEP 1969

Pagination or Media Count : 41

Abstract : The nature and some details of the elasto-plastic strain distribution ahead of the crack tip in an edge-cracked sheet has been determined by experiment and analysis. The experiment uses the optical interference and moire techniques. The analysis is a generalized plane stress model using the finite element method; the measured uniaxial stress-strain properties of the materials are used as input to the analysis. Materials investigated by one or both methods are 1018 steel, copper, 90-10 and 70-30 brass, and 6061-T6 aluminum. Of these materials, meaningful comparisons between experiment and analysis have been made for those with no discontinuity in uniaxial behavior; copper, 90-10 brass, and aluminum. The agreement between experiment and analysis can be significantly affected by how well the early, uniaxial, yield properties used in the analysis represent the actual properties of the experimental specimens. The main factors which control the general nature of crack-tip strain are (1) degree of strain hardening, shown by both experimental and analytical results and (2) thickness of the experimental specimen. For materials of low strain hardening and at relatively low loads, the measured crack-tip deformation tends to be three dimensional in character and restricted in extent to about one specimen thickness in the direction normal to the crack. For higher hardening and at higher loads, broader, two-dimensional strain distributions result with better correlation with analysis. Stress distributions from the analysis in the area ahead of the crack are also shown and tend to support the strain results. (Author)

Descriptors :   (*SHEETS, STRAIN(MECHANICS)), FRACTURE(MECHANICS), STRESSES, BRASS, ALUMINUM ALLOYS, STEEL, STRAIN HARDENING

Subject Categories : Metallurgy and Metallography
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE