SEDL / STP / STP982-EB / STP27221S

Correlation Between Numerically Predicted Crack Opening Load and Measured Load History Dependent Crack Growth Threshold

Anquez, L
Research engineers, Office National d'Etudes et de Recherches Aérospatiales, Chatillon Cedex,

Baudin, G
Research engineers, Office National d'Etudes et de Recherches Aérospatiales, Chatillon Cedex,

Pages: 18    Published: Jan 1988

Download this paper for $25 PDF (228K)          View License Agreement
Abstract

The present paper deals with the application of a two-dimensional (plane stress) elastoplastic (Prager's flow rule) finite—element analysis to predict crack opening stresses during the crack growth process under cyclic loading. The main results obtained are as follows:

Crack closure is achieved at crack tip as soon as unloading begins. Under constant amplitude loading, the ratio of the opening force to the maximum force is nearly constant and in good accordance with experiment. ΔK^eff is an appropriate parameter if and only if some plastic strain correlations are satisfied around crack tip. This is the case in two-level (HiLo) loadings; so it is possible to have an evident explanation of crack arrest phenomenon. Comparisons with experiments are, in this case, quite satisfactory.