SYMPOSIA PAPER Published: 01 January 1977

Fracture Toughness Testing Using the C-Shaped Specimen


Fracture toughness testing of material with cylindrical geometry is discussed, and the inherent advantages of the C-shaped specimen in this situation are given. A K calibration equation for the C-shaped specimen is presented which is based on boundary value collocation results. The C-shaped specimen K calibration is compared with those for the standard compact specimen and the single-edge-notched bar specimen.

Guidelines for measuring plane-strain fracture toughness (KIc) using the C-shaped specimen are described, including (a) a KI calibration which applies over a wide range of diameter ratios and to two load point locations in segments of hollow cylinders, as well as over a range of crack lengths, (b) compliance and crack-mouth-displacement analyses and their use to obtain critical value of KI in a fracture toughness test, and (c) suggested specimen geometries to be used in performing KIc tests with C-shaped specimens.

The use of C-shaped specimens for performing J-integral fracture toughness tests and fatigue crack growth tests is described, and some preliminary testing guidelines are offered. Included are suggested methods of load-point-displacement measurement for J-integral tests and suggestions for the geometry and K calibration which could be used in fatigue tests.

Author Information

Underwood, JH
U.S. Army Benet Weapons Laboratory, Watervliet, N.Y.
Kendall, DP
U.S. Army Benet Weapons Laboratory, Watervliet, N.Y.
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Developed by Committee: E08
Pages: 25–38
DOI: 10.1520/STP28698S
ISBN-EB: 978-0-8031-4704-1
ISBN-13: 978-0-8031-0321-4