Division head, Deutsche Forschungs- und Versuchsanstalt fur Luft- und Raumfahrt, Cologne, FR
Pages: 20 Published: Jan 1979
The minimum thickness and the minimum ligaent width for the determination of plane-strain fracture toughness with linear-elastic methods can be considerably smaller than given by the ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-74). For the ligament width, the factor 2.5 in the size requirement equation can be replaced at least by 1, possibly by 0.4. The size dependence of KQ determined with the 5 percent secant method is due to plasticity at the crack tip and to the existence of a rising plane-strain crack growth resistance curve. With a variable secant, adjusted to the specimen width, it is possible to determine size-independent fracture toughness values.
fracture properties, crack propagation, toughness, tests, aluminium alloys
Paper ID: STP35841S