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.

Issue Section:
Research Papers
Keywords:
fatigue crack growth, crack growth rate, stress intensity factor

References

1.
James
,
L. A.
, “
Specimens Size Considerations in Fatigue Crack Growth Rate Testing
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
45
-
57
.
2.
Yoder
,
G. R.
,
Cooley
,
L. A.
, and
Crooker
,
T. W.
, “
Procedures for Precision Measurement of Fatigue Crack Growth Rate Using Crack-Opening Displacement Techniques
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
85
-
102
.
3.
Bastenaire
,
F.
,
Lieurade
,
H. P.
,
Regnier
,
L.
, and
Truchon
,
M.
, “
Statistical Analysis of Fatigue Crack Growth
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
163
-
170
.
4.
Fong
,
J. T.
 and
Dowling
,
N. E.
, “
Analysis of Fatigue Crack Growth Rate Data from Different Laboratories
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
171
-
193
.
5.
Ostergaard
,
D. F.
,
Thomas
, Jr., and
Hillberry
,
B. M.
, “
Effect of Δa Increment on Calculating da/dN from a versus N Data
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
194
-
204
.
6.
Miller
,
M. S.
 and
Gallagher
,
J. P.
, “
An Analysis of Several Fatigue Crack Growth Rate (FCGR) Descriptions
,”
Fatigue Crack Growth Measurement and Data Analysis
, ASTM STP 738,
Hudak
,
S. J.
 Jr. and
Bucci
 
R. J.
, Eds.,
American Society for Testing and Materials
,
Philadelphia
,
1981
, pp.
205
-
251
.
This content is only available via PDF.
All rights reserved. This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of ASTM International.
You do not currently have access to this content.