THRESHOLD CRACK GROWTH IN A36 STEEL

Objectives of the study were to investigate the regions of high cycle and threshold fatigue crack propagation and to correlate the findings with observed results from tests of welded structural details. The crack propagation phase focused on cycling plate specimens at low ranges of stress to determine levels of stress for which no crack extension appeared. Results indicated a definite trend towards a threshold for fatigue crack propagation. Through a fracture mechanics analysis this threshold region of cyclic stress was described in terms of the range of the stress intensity factor for the plate specimens. The crack growth and threshold value were used to predict stress ranges which would not cause failure at the weld toe of cover plates fillet-welded to beam flanges. A mathematical model was used to relate the stress conditions existing at the weld toe to the stress applied on the detail. Using the threshold value of the stress intensity factor range found in the crack growth studies, a runout stress range was derived which agreed well with results of coverplated beam studies.

• Supplemental Notes:
  • Report on High Cycle Fatigue of Welded Bridge Details. Prepared in cooperation with Federal Highway Administration, Washington, D.C.
• Corporate Authors:

  Lehigh University

  Fritz Engineering Laboratory
  Bethlehem, PA  United States  18015

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  Pennsylvania Department of Transportation

  Commonwealth and Forster Streets
  Harrisburg, PA  United States  17120
• Authors:
  • Klingerman, D J
  • Fisher, J W
• Publication Date: 1973-9

Media Info

• Pagination: 61 p.

Subject/Index Terms

• TRT Terms: Alloy steel; Beams; Cracking; Failure; Fatigue cracking; Forecasting; Fracture mechanics; High strength steel; Joints; Mathematical models; Mechanical fatigue; Metallurgy; Steel plates; Stresses; Structural steel; Welds
• Uncontrolled Terms: Crack propagation; Thresholds; Welded joints
• Old TRIS Terms: Stress cycle; Welded steel beams
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00090547
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: FEL-386.2 Intrm Rpt.
• Files: NTIS, TRIS, USDOT, STATEDOT
• Created Date: May 29 1975 12:00AM