Comparison between long and short beam flexure of a carbon fibre based FML

A Fibre metal laminate (FML) consists of a stack of metal sheets alternating to composite material layers: in such a manner, the best characteristics of both constituents are combined together. In this work, the flexural behaviour of different kinds of FMLs was investigated. In particular, both long beam and short beam specimens were produced and tested, since the length-to-thickness ratio influences the stress type arising in the material and, consequently, the failure mode. Moreover, the influence of both the composite/metal interface and the thickness of the layers was analysed. It was found that the structural adhesive was deleterious for the flexural strength of the long beam, while it improved the behaviour of the short one. As concerns the thickness and the distribution of the layers, this factor was unaffecting for the short beam specimen, while it was decisive for the long beam one. A micrographic analysis was carried out on the tested specimens, in order to characterize the failure mode. It was found a preponderance of fibre breakage in the long beam, while in the short one the failure of the metal/composite interface was prevailing. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of MedFract1 organizers