Failure of Adhesively Bonded Composite Stiffeners; a Blind Analysis Challenge

This paper presents the work of the NCC and University of Bristol for the first stage of the Composite Blind Analysis Challenge (CBAC). In this challenge, the Five Eyes Science and Technology (FVEY S&T) organisation tasked participants with predicting the behaviour of element-level composite bonded structures loaded to destruction. These consisted of a T-stringer adhesively bonded to a skin panel in three configurations; pristine and with embedded defects at either the tip or central throat of the bondline. Each configuration was subjected to two load cases; T-Pull and Side-Bend. Finite Element simulations featuring a custom-developed Cohesive Zone Model (CZM) were used to predict the initiation and propagation of delamination and debonding in each case. These blind predictions are presented together with correlation to experimental test results and a description of the methodology used.