Fatigue of As-Fabricated Open Cell Aluminum Foams

This paper presents the results of the combined experimental investigation and digital image correlation (DIC) analysis of the fatigue failure of open cell aluminum foams. Compression-compression cyclic loads were applied to foam specimens under the as-fabricated condition. Following characterization of the S-N curve behavior, the macroscale deformation of the tested foam under fatigue was recorded using an in-situ digital camera. The deformation sequence was then analyzed using DIC technique. It was found that foams failed with an abrupt strain jump when shear bands were formed, and serious deformation up to more than 30% was developed in the center of the shear band. The ex-situ scanning electron microscopy analysis indicated that the abrupt strain jump was due to the microscale damage accumulation in struts where surface cracks were formed and propagated.