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A PROCEDURE TO MINIMISE ERROR IN FATIGUE CRACK GROWTH TESTING
Author(s) -
Oore M.
Publication year - 1995
Publication title -
fatigue and fracture of engineering materials and structures
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 84
eISSN - 1460-2695
pISSN - 8756-758X
DOI - 10.1111/j.1460-2695.1995.tb00914.x
Subject(s) - paris' law , interval (graph theory) , test data , structural engineering , mathematics , approximation error , fracture mechanics , secant method , materials science , statistics , crack closure , computer science , engineering , newton's method , physics , combinatorics , nonlinear system , quantum mechanics , programming language
A concept for minimising the error associated with the K gradient and the interval of crack length measurement in fatigue crack growth testing has been extended to include crack configurations where crack size is significant relative to specimen width. This was used to develop a procedure for deriving the d a /d n vs. Δ K relationship from crack growth data. The procedure was applied to several test data, utilizing six measurement points of length vs. cycles data and experimenting with various sizes of crack measurement interval (up to 85% of crack size). The accuracy of the derived d a /d n vs. Δ K data was examined by comparison with the baseline data curves. The results were within a few per cent of the actual test data and were usually more accurate than those obtained by secant methods. Increasing the number of data points used in the analysis generally improved the accuracy of the present procedure more than it did with the standard secant method results.