THE EFFECTS OF THE SURFACE LAYER ON PLASTIC DEFORMATION AND CRACK PROPAGATION

The report describes the effect of a surface layer on the rate of crack propagation and, based on this knowledge, the author proposes to improve the crack propagation resistance of metals used in pressure vessels. The qualification of pressure vessel hardware is usually achieved by the proof test method. The maximum size of the flaw that is present can be predicted from fracture mechanics. However, cracks can grow below the critical stress intensity K sub c and can cause leak failure. Therefore, the subcritical crack growth characteristics of metals are important in pressure vessel material selection. An evaluation of the crack growth rate under sustained or cyclic loading under the service stress gives a measure of reliability of the hardware. (Author)

• Corporate Authors:

  Martin Marietta Corporation

  P.O. Box 179
  Denver, CO  United States  80201
• Authors:
  • Kramer, I R
• Publication Date: 1971-3

Media Info

• Pagination: 15 p.

Subject/Index Terms

• TRT Terms: Cracking; Fatigue (Mechanics); Fracture mechanics; Repeated loads
• Uncontrolled Terms: Crack propagation; Fatigue life
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00016725
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: CR-71-2, AMMRC-CR-71-2/1
• Contract Numbers: DAAG46-70-C-0102, ARPA Order-180
• Files: TRIS
• Created Date: Oct 29 1972 12:00AM