Data reduction methods in the fatigue analysis of the Double Cantilever Beam, Part II: Evaluation and case studies

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 structures. Regardless, to date, no standard exists to evaluate the Mode-I fatigue properties of adhesively bonded joints nor for delamination of composite structures. In part II of this work, virtual fatigue tests are used to explore several reduction schemes that have been employed by researchers to characterize the Paris law coefficients. The results show that different reduction methods can yield different Paris curves when the measurement of the actual crack size is used, and the discrepancy among the methods increases as the global stiffness of the joint increases. However, when the concept of equivalent crack is used, the performance of most reduction methods increases significantly. The results show that the use of the equivalent crack concept combined with an appropriate reduction method can yield very accurate results, sparing cumbersome crack length measurements altogether.