Growth and coalescence of multiple fatigue cracks in polycarbonate test specimens

Abstract This paper presents the results of an experimental study of fatigue crack coalescence and interaction in transparent polycarbonate test specimens. The specimen geometries studied were a plate with a centered hole loaded in remote tension and a beam subjected to cyclic bending. Each specimen contained an initial pair of surface and/or corner cracks which were grown until coalescence of the two flaws occurred. Crack length vs elapsed cycles data generated from the tests were compared with predictions made by a computer algorithm. Good predictions were obtained for the period required for the two initial flaws to coalesce, but the numerical results were somewhat conservative after the cracks coalesced into a single flaw.