A STUDY OF PLASTIC DEFORMATION AND FRACTURING BY STRAIN ENERGY DISTRIBUTION

This investigation was conducted to study the plastic deformation and fracturing of 12 inch wide, 3/4 inch thick internally notched steel plates under axial tension by determining the strain energy distribution on the surface of the deformed regions of the plates. Several stages in the process of deformation and fracturing at 70 deg F and 10 deg F were investigated to maximum load, 70 deg F being above the transition temperature, and 10 deg F being below the transition temperature. Surface strain energy distribution across the crack was also determined for a specimen fractured ductilely at 70 deg F. By using the octahedral theory in connection with the assumption of incompressibility and the assumption that the principal coordinate system is parallel to the three dimensions of the plate, the unit energies on the surface of the plate were obtained from grid measurements. By assuming that the energy distribution is independent of the thickness dimension. Total energy is obtained for comparison with the total energy input measured from the load-elongation curve. The results of this investigation show that the total energy based on octahedral theory and the above-stated assumptions agrees very well with the total observed energy input; that the rate of propagation of plastic deformation with respect to energy input decreases with decreasing temperature; that, for specimens with two dimensional similarity and constant thickness, the total energy of individual specimens of varying width can be predicted by the strain energy distribution of a single specimen of proper width; and that, at room temperature, the unit strain energy at the crack is found to be approximately in the order of 30,000 in-lbs per cubic inch in a ductile specimen.

  • Corporate Authors:

    Swarthmore College

    Division of Engineering
    Swarthmore, PA  United States 

    Ship Structure Committee

    National Academy of Science, 2101 Constitution Avenue, NW
    Washington, DC  United States  20418
  • Authors:
    • Liu, S I
    • Carpenter, S T
  • Publication Date: 1950-12-20

Media Info

  • Features: References;
  • Pagination: 37 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00330988
  • Record Type: Publication
  • Source Agency: Ship Structure Committee
  • Report/Paper Numbers: SSC- 38 Prog Rpt.
  • Contract Numbers: NObs-45521, NObs-50148
  • Files: TRIS
  • Created Date: May 21 1981 12:00AM