Session: 02-14-03 Structural Analysis of Marine Structures 3

Submission Number: 179832

Shell to Solid Submodeling With Cohesive Elements for Delamination Analysis of Top-Hat Stiffened Composite Panels 

Glass fiber reinforced plastics are widely used in the manufacturing of pleasure boats. Top hat stiffened panels represent the current state of the art of such structural components, being structurally efficient and easy to manufacture. By the way, the stiffener to hull bondline can be vulnerable to delamination under in plane compression. Class rules such as NR546 provide detailed procedures for ply strength and for local and global buckling verification, but they address delamination only briefly through simplified stress based criteria. This work presents an automated Python workflow that follows NR546 ply checks and extends them with a detailed delamination assessment. A global layered shell model checks the plies against a standard failure criterion by the well assessed classic laminate theory to detect the first ply failure. Then, a local solid submodel with cohesive zone elements resolves the stiffener to hull interface. Shell displacements are applied to the submodel, where a bilinear traction separation law captures debonding initiation and growth. Geometry and material definitions are defined as parametric input, to enable rapid design iterations. The approach is demonstrated on a top hat stiffened composite panel subjected to in plane compressive loading. Mesh density in the cohesive region is selected using process zone length estimates and convergence studies, including through thickness element requirements. The method combines rule based ply strength checks with detailed delamination analysis for design decision making.

Presenting Author: Nils-Erik Sanhen University of Genoa

Presenting Author Biography: - B. Sc. in Product Development and Production at the Hamburg University of Technology, 2019
- M. Sc. in Product Development, Materials and Production at the Hamburg University of Technology, 2022
- Research Assistant at the Institute for Ship Structural Design and Analysis, Hamburg University of Technology, 2022-23
- Ph.D. student at Dipartimento di Ingegneria Navale, Elettrica, Elettronica e delle Telecomunicazioni, University of Genova, 2023-present

Authors:

Nils-Erik Sanhen University of Genoa
Marco Gaiotti University of Genoa