Brittle fracture of full scale structures damaged by fatigue 1 2

Abstract

Tests are discussed with full scale structural specimens which were loaded to rupture at low temperatures after being subjected to low cycle fatigue loading. (Axial loading: ${\mathit{P}}_{\min }\mathrm{/}{\mathit{P}}_{\max }=-\phantom{\mathrm{(}}1\mathrm{/}\phantom{\mathrm{(}}2$ ).

It has been found that fatigue seriously reduces the plastic deformability prior to brittle fracture. This seems to be mainly due to the presence of fatigue cracks and not to deterioration of the material caused by the fatigue loading. The influence of crack length was small.

The high stress – low stress transition of the specimens was much lower than transition temperatures obtained with well-known acceptance tests. In an additional investigation it could be proved that this large difference is a consequence of the pure static character of the final tests to rupture. The results strongly suggest that the high stress-low stress transition of the full scale specimens might be raised up to N.D.T. by pure elastic shock loading.