Determining Effective Interface Fracture Properties of 3D Fiber Reinforced Foam Core Sandwich Structures

Foam core sandwich composites are finding a wider breadth of use in aerospace, automotive, and construction applications. These structures present unique challenges in terms of material failure and interaction and are highly sensitive to damage and imperfections introduced during manufacturing. An emerging class of 3D Fiber Reinforced Foam Core (3DFRFC) aims to replace monolithic foams used in sandwich structure cores particularly in demanding high performance aerospace applications. This research is focused on investigating the development of testing methods capable of measuring the effective interface fracture properties between the facesheet and the core in 3DFRFCs. Double Cantilever Beam and EndNotched Flexure specimens are developed to evaluate the Mode I and Mode II fracture properties of a 3DFRFC. Preliminary nonlinear finite element analysis with a progressive failure methodology is used to understand the delamination propagation and aid in specimen development. 3DFRFC panels for fracture testing are manufactured and experimental testing will follow final specimen fabrication.