Minimization and Quantification of Error Associated with the <i>K</i> Gradient and the Interval of Crack Length Measurement in Fatigue Crack Growth Testing

Volume 21, Issue 2 (March 1993)

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ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 7

Minimization and Quantification of Error Associated with the K Gradient and the Interval of Crack Length Measurement in Fatigue Crack Growth Testing

Oore, M
IMP AEROSPACE, Halifax, Nova Scotia,

(Received 27 April 1992; accepted 7 October 1992)

Abstract

Analytical method has been developed to minimize and quantify the effect of crack length measurement interval Δa on the error due to the K gradient in the interpretation of da dN derived from crack growth test data using the secant method. The associated error has been quantified in a general form and used to demonstrate the specific errors due to the selection of average crack length a per ASTM E 647-91. Test Method for Measurements of Fatigue Crack Growth Rates. It is shown that the selection of the geometric mean (a¯=a1a2) in the data analysis will reduce the associated error in the crack growth rate interpretation. It is recommended that ASTM E 647-91 be revised accordingly.

Keywords:
fatigue crack growth, crack growth rate, stress intensity factor

Paper ID: JTE11752J
DOI: 10.1520/JTE11752J
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Author Title Minimization and Quantification of Error Associated with the K Gradient and the Interval of Crack Length Measurement in Fatigue Crack Growth Testing Symposium , 0000-00-00 Committee E08

		SEDL / Journals / Journal of Testing and Evaluation (JTE) / Citation Page Volume 21, Issue 2 (March 1993) Click here to download this paper now for $25 PDF (404K) View License Agreement ISSN: 1945-7553 CODEN: JTEVAB Page Count: 7 Minimization and Quantification of Error Associated with the K Gradient and the Interval of Crack Length Measurement in Fatigue Crack Growth Testing Oore, M IMP AEROSPACE, Halifax, Nova Scotia, (Received 27 April 1992; accepted 7 October 1992) Abstract Analytical method has been developed to minimize and quantify the effect of crack length measurement interval Δa on the error due to the K gradient in the interpretation of da dN derived from crack growth test data using the secant method. The associated error has been quantified in a general form and used to demonstrate the specific errors due to the selection of average crack length a per ASTM E 647-91. Test Method for Measurements of Fatigue Crack Growth Rates. It is shown that the selection of the geometric mean (a¯=a1a2) in the data analysis will reduce the associated error in the crack growth rate interpretation. It is recommended that ASTM E 647-91 be revised accordingly. Keywords: fatigue crack growth, crack growth rate, stress intensity factor Paper ID: JTE11752J DOI: 10.1520/JTE11752J ASTM International is a member of CrossRef. Author Title Minimization and Quantification of Error Associated with the K Gradient and the Interval of Crack Length Measurement in Fatigue Crack Growth Testing Symposium , 0000-00-00 Committee E08