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  United States  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

• TRT Terms: Beams; Cracking; Fracture properties; Stresses
• Identifier Terms: Ship Structure Committee
• Uncontrolled Terms: Crack propagation; Stress intensity factors
• Old TRIS Terms: Cantilever beams; Crack arrest
• Subject Areas: Marine Transportation; Materials;

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