Study of Skin-Stringer Separation in Postbuckled Composite Aeronautical Structures

Luc Kootte, Chiara Bisagni, Carlos Davila, Vipul Ranatunga

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

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Abstract

Aeronautical composite stiffened structures have the capability to carry loads deep into postbuckling, yet they are typically designed to operate below the buckling load to avoid potential issues with durability and structural integrity. Large out-of-plane postbuckling deformation of the skin can result in the opening of the skin-stringer interfaces, especially in the presence of defects, such as impact damage. To ensure that skin-stringer separation does not propagate in an unstable mode that can cause a complete collapse of the structure, a deeper understanding of the interaction between the postbuckling deformation and the development of damage is required. The present study represents a first step towards a methodology based on analysis and experiments to assess and improve the strength, life, and damage tolerance of stiffened composite structures subjected to postbuckling deformations. Two regions were identified in a four-stringer panel in which skin-stringer separation can occur, namely the region of maximum deflection and the region of maximum twisting. Both regions have been studied using a finite element model of a representative single-stringer specimen. For the region of maximum deflection, a seven-point bending configuration was used, in which five supports and two loading points induce buckling waves to the specimen. The region of maximum twisting was studied using an edge crack torsion configuration, with two supports and two loading points. These two configurations were studied by changing the positions of the supports and the loading points. An optimization procedure was carried out to minimize the error between the out-of-plane deformation of the representative single-stringer specimen and the corresponding region of the fourstringer panel.
Original languageEnglish
Title of host publicationProceedings of the American Society for Composites Thirty-third Technical Conference
Pages1750 - 1761
DOIs
Publication statusPublished - 2018
Event33rd Technical Conference of the American Society for Composites 2018 - Seattle, United States
Duration: 24 Sept 201827 Sept 2018

Conference

Conference33rd Technical Conference of the American Society for Composites 2018
Country/TerritoryUnited States
CitySeattle
Period24/09/1827/09/18

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