Design Considerations for a Compressed Stiffened Plate with Skin–Stringer Debonding Based on the Evaluation of Adhesive Layer Stress Distribution

An extensive application of stiffened panels is considered standard for aerospace wing construction both for reducing the structural weight and fulfilling the regulatory requirements. The connection based on the adhesive layer between the skin and stringer introduces the possibility of debonding during operative conditions. The design procedure is strongly influenced by this anomaly, requiring the definition of a criterion for identifying the limit in debonding extension for safe operation. A procedure based on the investiga tion of the stress state in the adhesive layer is proposed in order to identify the typical behaviour of compressed plate, including damage situation, and a specific indication for design procedure is derived based on the debonding dimension. Critical and post-critical configuration were investigated both globally and locally to fix sensitive parameters. A con clusive guideline is discussed and presented. The analysis is applied to an isotropic plate in order to point out the main characteristics of the related design procedure. No conceptual changes are expected with the introduction of composite material that can influence the distribution of stress according to the chosen lay-up but not the basic design concept in the plate behaviour.