Flexural-Fatigue Evaluation of Aluminum-Alloy and Kraft-Paper Honeycomb-Sandwich Beams

Flexural static and fatigue tests were conducted on 3$14$-in.-thick honeycomb-sandwich beams having either aluminum-alloy or kraft-paper cores and identical aluminum facings. When the beams have relatively small ratios of length to thickness (short spans, thick cores), the static and fatigue strengths are determined primarily by the shear properties of the core material. In this case, the aluminum honeycomb sandwich was stronger than the kraft-paper honeycomb sandwich. With longer beams, the strengths are dependent mainly on the properties of the facing materials. Since the facings were the same for the two types of sandwiches, the respective static and fatigue properties were approximately equal.