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Evaluation of fatigue-crack growth rates by polynomial curve fittingFundamental characterization of the constant-amplitude fatigue crack propagation is achieved by an analysis of the rate of change of crack length with change in number of applied loading cycles, defining the rate values such that they are consistent with the basic assumption of smoothness and continuity in the fatigue crack growth process. The technique used to satisfy the analytical conditions and minimize the effects of local material anomalies and experimental errors is that of fitting a smooth curve to the entire set of basic data by least square regression. This yields a well-behaved function relating the number of cycles to the crack length. By taking the first derivative of the function, the crack growth rate is obtained for each point. The class of curve fitting functions used in the analysis is the polynomial of degree n.
Document ID
19740029787
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Davies, K. B.
Feddersen, C. E.
(Battelle Columbus Laboratories Columbus, Ohio, United States)
Date Acquired
August 7, 2013
Publication Date
March 1, 1973
Publication Information
Publication: International Journal of Fracture
Volume: 9
Subject Category
Structural Mechanics
Accession Number
74A12537
Distribution Limits
Public
Copyright
Other

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