Sizing a single cantilever beam specimen for characterizing facesheet–core debonding in sandwich structure

Abstract

This article details a procedure for sizing single cantilever beam (SCB) test specimens that are used to characterize facesheet–core debonding in sandwich structure. The characterization is accomplished by measuring the critical strain energy release rate, Gc, associated with the debonding process. The sizing procedure is based on an analytical representation of the SCB specimen, which models the specimen as a cantilever beam partially supported on an elastic foundation. This results in an approximate, closed-form solution for the compliance–debond length relationship of the specimen. The solution provides a series of limitations that can be imposed on the specimen dimensions to help ensure the specimen behaviour does not violate assumptions made in the derivation of the data reduction method used to calculate Gc. Application of the sizing procedure to actual sandwich systems yielded SCB specimen dimensions that would be practical for use. The method is specifically configured for incorporation into a draft testing protocol to be developed into an ASTM International testing standard.