Data reduction methods in the fatigue analysis of the Double Cantilever Beam, Part I: Fundaments and virtual fatigue testing

Abstract

The characterization of high-cycle crack growth properties of bonded joints is an important research field with a direct impact on the practical engineering and designing of composite structures. Regardless, to date, no standard exists to evaluate the Mode-I fatigue properties of adhesively bonded joints, and thus several different reduction approaches have been used by researchers. In part I of this work, we explore these approaches and show what differences emerge when trying to obtain the rate of crack propagation curves traditionally used in fatigue analysis. A difference of more than 2.5 times in the rate of crack propagation was observed depending on the method used in the analysis. It is further shown that the discrepancies in the results decrease drastically when the equivalent crack concept is employed, rather than relying on visual crack measurements. Finally, it is proposed that virtual fatigue tests can be used to investigate the accuracy of the different reduction methods.