PLASTIC FLOW AROUND A CRACK UNDER FRICTION AND COMBINED STRESS

A boundary integral relaxation method was used to calculate the plasticity at the tip of a small horizontal crack buried in a rail head. The Hertz equations were used as boundary conditions, along with axial residual stress. A wheel passage gives initial sliding, followed by locking, squeezing the plastic zone, reversed sliding, locking, and finally unloading. Computing four cycles of this rail stress history cost $51. At steady state (only three cycles), the plastic zone extended in the shear direction almost exactly as far as predicted from linear elastic fracture mechanics, in spite of the compression being 8 times the net shear tending to produce Mode II. The crack always remained closed. Reversed shearing on cross-slip planes was no more than 10% of that on the segment directly in front of the crack. Some speculations are given about a fracture criterion in terms of the displacements and the compressive stresses.

Media Info

  • Features: References;
  • Pagination: p. 23-38

Subject/Index Terms

Filing Info

  • Accession Number: 00184648
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: Volume 4 Proceeding
  • Files: TRIS
  • Created Date: Dec 29 1978 12:00AM