A CRITICAL SURVEY OF BRITTLE FRACTURE IN CARBON PLATE STEEL STRUCTURES, OTHER THAN SHIPS

The failure of ships at sea and at dockside during World War II brought the problem of brittle fracture into sharp focus. Data from ship failures have been well correlated, and as a result, much has been learned from research stimulated thereby. No similar correlation on nonship failure data exists, and this survey was therefore undertaken in order to supplement the study of ship failures. A total of 64 structural failures, plus failures in gas transmission lines, was studied. These failures occurred in both riveted and welded structures such as tanks, bridges, pressure vessels, a smoke stack, a penstock, power shovels, as well as gas transmission lines. It is shown that the history of brittle failure extends back at least to 1879. It is con- cluded that: (1) Brittle failure in nonstop structures is the same phenomenon as occurs in ships; (2) brittle failure occurs in many types of nonship structures; (3) brittle fractures can cross riveted joints; (4) there is no evidence to show that the percentage incidence of brittle failure has either decreased or increased with the advent of weld- ing; (5) in conjunction with other factors, thermal stress may be important; (6) residual stresses are not the prime cause of brittle failure, but such stresses may, in con- junction with other factors, initiate such failure; (7) the effect of metallurgical variables is important; (8) cold forming promotes susceptibility to brittle failure, but its role cannot be assessed due to lack of data; (9) in such cases where data are available, Charpy impact values of plate were generally low at the failure temperature; ( 10 ) in most cases of nonship brittle failure, the fracture originated at defects arising from fabrication. A few originated at design defects; ( 11 ) it seems evident in all cases that fracture originated at a geometric discontinuity; ( 12 ) no evidence exists for these failed structures to show the effects of various welding processes on susceptibility to brittle failure; ( 13 ) except in the case of exceptionally poor welds, there is no tendency for fracture to follow welded seams; ( 14 ) the great majority of nonship brittle failures apparently occur under conditions of entirely static loading; ( 15 ) age of structure seems to have no bearing on brittle failure; ( 16 ) most engineering codes permit the use of steel which is known to be particularly susceptible to brittle failure. At the same time, under all codes but one, the stress levels are held to quite conservative values; ( 17 ) finally, it is demonstrated that brittle failure results from a combination of many factors. There is no readily available material which would entirely prevent its occurrence, and there is no known test which will surely preduct from the behavior of small specimens the performance of a given steel in circumstances where structural brittle failure might occur. In short, careful design, selection of materials, and good workmanship are of the greatest importance in the prevention of brittle failure in nonship structures. This is true of ships.

• Supplemental Notes:
  • Prepared for National Research Councils Committee on Ship Structural Design
• Corporate Authors:

  Ship Structure Committee

  National Academy of Science, 2101 Constitution Avenue, NW
  Washington, DC  United States  20418

  Bureau of Ships

  Washington, DC  United States 
• Authors:
  • Shank, M E
• Publication Date: 1953-12-1

Media Info

• Features: Figures; Photos; Tables;
• Pagination: 49 p.

Subject/Index Terms

• TRT Terms: Fracture mechanics; Joints; Pressure vessels; Welds
• Uncontrolled Terms: Welded joints
• Subject Areas: Marine Transportation; Materials;

Filing Info

• Accession Number: 00007502
• Record Type: Publication
• Report/Paper Numbers: SSC- 65
• Contract Numbers: NObs-50148
• Files: TRIS
• Created Date: Dec 22 1973 12:00AM