Development of fatigue cracks in complex mechanical structures

The paper summarizes some theoretical and experimental activities concerned with reliability problems of mechanical structures within advanced Czechoslovakian scientific and research institutions. The aim of the paper is directed to the system concept of the fatigue damage mechanism as acting on real mechanical structures in real operational conditions or in those being simulated in laboratories. Such a concept—which has long been emphasized by Prof. A. M. Freudenthal—is based herein on the knowledge gained by studying large-scale structure failures namely in aeronautics.