Load-carrying capacity of cold bonded inserts oriented parallel to facings on honeycomb sandwich panels used in aero-structures applications

Structure sandwich panels with honeycomb cores are widely used in the aerospace industry due to their excellent mechanical properties. However, their structural performance is strongly governed by load introduction points, where mechanical inserts play a critical role in transferring the localized loads between the face-sheets and the core, as well as other various structural elements attached. Most existing studies on potted inserts have focused on inserts oriented perpendicular to the face-sheets, while other configurations remain insufficiently investigated, like inserts oriented parallel to face-sheets. This study focuses on load-carrying capacity and characterizes the mechanical performance of potted inserts oriented parallel to the face-sheets in the sandwich structure under various loading forms. The bonded joints with standard metallic inserts used in the present investigation are potted into the honeycomb core panel with a cold bonded process. The specimens were tested under three different static loadings: in-plane pull-out insert, in-plane shear insert, and out-of-plane insert tests. The mechanical behavior and failure mechanisms of the cold-bonded inserts placed parallel to the facings are described in detail for each load case. Afterwards, finite element analysis is performed to investigate the stress fields. Finally, the obtained results for three different loadings are compared with static strength capability results obtained from the FE model, and the load capacity as well as the applicability of the boundary insert are identified.