FAST FRACTURE RESISTANCE AND CRACK ARREST IN STRUCTURAL STEELS

This report presents findings of an Army Research Office supported study concerned with the response of high-strength steels to fast running cracks, and a separate Ship Structure Committee program dealing with unstable fractures in ship plates. Together, the results provide a new basis for measuring and characterizing the properties of structural alloys that control fast fracture and crack arrest. Measurements and calculations of unstable fracture and fracture arrest in 12.7 mm- and 25.4 mm-thick, high-strength SAE4340 steel and A517F steel plates are described. The unstable fractures which propagated at steady-state velocities in the range 185 m/s to 1180 m/s were produced in wedge-loaded DCB- (double-cantilever-beam) test specimens. The study demonstrates a new concept: the "duplex" DCB-specimen. A fully dynamic analysis of unstable crack propagation and arrest in the DCB-test piece is derived. The technique is based on the beam-on-elastic foundation model of the DCB specimen used previously but with the simple beam and foundation representations replaced by a Timoshenko beam and a generalized elastic foundation. Crack speeds, energy levels, and the crack length at arrest are calculated with this model using a finite-difference method and are compared with the measurements.

  • Supplemental Notes:
    • Progress report on Fracture Arrest Study (SR-201), MRIS 052047-23A.
  • Corporate Authors:

    Ship Structure Committee

    National Academy of Science, 2101 Constitution Avenue, NW
    Washington, DC  USA  20418
  • Authors:
    • Hahn, G T
    • Hoagland, R G
    • Kanninen, M
    • Rosenfield, A R
    • Sejnoha, R
  • Publication Date: 1973-12

Media Info

  • Features: Appendices; References;
  • Pagination: 113 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00052139
  • Record Type: Publication
  • Source Agency: Ship Structure Committee
  • Report/Paper Numbers: SSC-242 Prog Rpt
  • Contract Numbers: N00024-72-C-5142
  • Files: TRIS
  • Created Date: Apr 26 1974 12:00AM