SYMPOSIA PAPER Published: 01 January 1989

Automated Generation of Influence Functions for Planar Crack Problems


A numerical procedure for the generation of influence functions for Mode I planar problems is described. The resulting influence functions are in a form for convenient evaluation of stress-intensity factors for complex stress distributions. Crack surface displacements are obtained by a least-squares solution of the Williams eigenfunction expansion for displacements in a cracked body. Discrete values of the influence function, evaluated using the crack surface displacements, are curve fit using an assumed functional form. The assumed functional form includes appropriate limit-behavior terms for very deep and very shallow cracks. Continuous representation of the influence function provides a convenient means for evaluating stress-intensity factors for arbitrary stress distributions by numerical integration. The procedure is demonstrated for an edge-cracked strip and a radially cracked disk. Comparisons with available published results demonstrate the accuracy of the procedure.

Author Information

Sire, RA
Failure Analysis Associates, Inc., Palo Alto, CA
Harris, DO
Failure Analysis Associates, Inc., Palo Alto, CA
Eason, ED
Modeling and Computing Services, Sunnyvale, CA
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Developed by Committee: E08
Pages: 351–365
DOI: 10.1520/STP18832S
ISBN-EB: 978-0-8031-5081-2
ISBN-13: 978-0-8031-1250-6