Finite element modeling of face/core interface fracture in homogenized honeycomb core sandwich SCB specimens

Fracture mechanics analysis of a face/core interface crack in a honeycomb core sandwich under mode I-dominated loading conditions is considered. The main objective of the study is to examine how to represent the homogenized in-plane extensional properties of hexagonal honeycomb core under deformation constraints due to bonding of the core to the face sheets. 2D parametric finite element analysis is conducted over a wide range of homogenized in-plane extensional properties of the core. The results show that plane stress assumption may lead to crack closure effects and highly distorted core elements for core with low in-plane modulus, while plane strain stabilizes the core deformation. Experimental results from SCB testing of a honeycomb core sandwich support the plane strain constrained modulus approach to face/core debond analysis.