A crack-opening-displacement technique for crack length measurement in fatigue crack growth rate testing—development and evaluation

✍ Scribed by A.M. Sullivan; T.W. Crooker

• Publisher: Elsevier Science
• Year: 1977
• Tongue: English
• Weight: 565 KB
• Volume: 9
• Category: Article
• ISSN: 0013-7944
• DOI: 10.1016/0013-7944(77)90061-3

✦ Synopsis

Ahstraet-A crack-o~n~~splacern~t (COD) technique has been successfuity employed to measure crack length in compact tension specimens for the ~te~~t~ of fatigue crack growth rate (FCGR). Details of the COD calibration and comparisons of COD-determined FCGR data with previously established trend lines for two high-strength steels are presented. Q crack length NOTATION ~l* initial crack length a/W crack lee-t~~dth ratio da/dN fatigue crack growth rate B specimen thickness COD crack-opening displacement CT compact tension specimen E Young's modulus FCGR fatigue crack growth rate I strain energy reiease rate Hz Hertz; cycles per second K stress-intensity factor AK stress-intensity range value (Kax -K,,,i,,} P load R stress ratio (a,&,) 2v total displacement W specimen width u grws or aominal stress Arr stress range value (a--cr,;.