Defect Assessment—Conclusion: Modified Ln-Secant equation improves failure prediction

10/13/2008
Limitations in the original Ln-Sec equation prompted development of a modified equation better suited thru the original equation for remaining life assessments. The modified Ln-Sec equation described in this concluding article slightly improves the failure stress prediction capability of the original. Even when including two poorly-fitting points, the modified Ln-Sec equation shows better correlation with the database of 35 full-scale experiments than the original Ln-Sec equation.Excluding the X100 experiments yields an average ratio of actual failure stress to predicted failure stress of 1.10, with a standard deviation of 0.13. This ratio would likely exceed 0.84 in 97.5% of cases and th...

Why Register?

Non-subscribers can only view whitepapers by providing name, home and email address, phone number and other information and comment on/rate articles.

Why Subscribe?

Oil & Gas Journal subscribers with login credentials can access these premium features of OGJ Online:

  • Current Issue – an html version of the current week's issue of Oil & Gas Journal.
  • Past Issues – An Electronic OGJ Archive. A keyword-searchable archive of all issues of Oil & Gas Journal dating back to 1990; also searchable by issue date.
  • Market Journal – a weekly round-up of the oil and gas markets, with observations from leading analysts.
  • Editor's Perspective – a short article of insight and opinion by the Editor of Oil & Gas Journal.
  • OGJ Industry Stats – quick access to current industry statistics from Oil & Gas Journal.
  • OGJ Survey Downloads - quick access to exclusive reports from Oil & Gas Journal.

 

Subscriber Help or Subscribe

Oil & Gas Journal Subscribers: Have your subscription number (from the mailing label on the cover of your Oil & Gas Journal) and e-mail address ready to set up your online account through Customer Service Assistant.

If you're not an Oil & Gas Journal subscriber, start a subscription and gain access to the subscriber areas of OGJ Online now.

ogj horizontal rule