Prediction of “Zed” section stringer pull-off loads

Closed-form analytical models are presented for predicting stringer pull-off loads for aircraft bonded stringer-skin construction in high-strength aluminium alloys. This was undertaken by modifying linear elastic fracture mechanics double cantilever beam analysis to accommodate simple single beams. The accuracy of the predictions was assessed by reference to experimental stringer pull-off strengths and to measured adherend displacements. Predictions of adherend displacement were also derived which included non-linear adhesive properties by numerical solutions of the governing differential equations. Comparison of these with experimental results showed better agreement than when using a linear elastic foundation.