Volume 16, Issue 1 (January 1988)
Determination of Material Characteristic Values in Elastic-Plastic Fracture Mechanics by Means of J-Integral Crack Resistance Curves
This article discusses the problem of determining the characteristic values in ductile fracture mechanics on the basis of the J-integral. Special interest is directed towards the question of transferability of the characteristic values from laboratory specimens to large-scale specimens of dimensions similar to those of components.
For this purpose technical substitute values and physical crack initiation characteristic values were determined from a number of specimens and a wide range of materials, showing the effect of material toughness and specimen geometry on the characteristic values. Technical substitute values were determined per ASTM (JIc), Loss et al. (J0.15), and Schwalbe and Heerens (J0.2). Determination of the physical crack initiation value resulted from measurements of the stretched zone.
The technical substitute values and the physical crack initiation values were compared with results for large-scale specimens. Only the physical crack initiation value (Ji) correctly described the behavior of large-scale specimens regarding crack initiation.