Enhanced nonlinear insert model
Résumé
Insert in composite sandwich structures sizing relies on simplified formulas based on beam theory. In reality, the failure scenario of inserts subjected to pull-out loading implies shear bucking and tears in Nomex honeycomb, debonding between metallic inserts and potting, debonding between potting and sandwich skins, static failure in the potting and skins and sometimes skins failures. An enhanced model (by comparison to the models developed by Bunyawanichakul et al. taking into account all the failure mode is developed. Cyclic shear tests are done to capture the shear bucking of the walls of a Nomex honeycomb cell (which is reversible) and the beginning of tearing (winch is irreversible). A technological test is also performed to model the debonding between a metallic insert and the potting. After validation with pull-out tests, the model is used to make failure mode maps useful for rapid sizing by engineers.