Investigation of failure initiation in curved composite laminates using a higher-order beam model

C. Thurnherr*, R. M J Groh, P. Ermanni, P. M. Weaver

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

6 Citations (Scopus)
255 Downloads (Pure)

Abstract

Curved laminates are prone to delamination failure from applied bending moments that straighten out the laminate and induce tensile stresses in the unreinforced radial direction. These non-classical through-thickness stresses are important even for thinner configurations and need to be accounted for in the design of lightweight composite structures, preferably in a computationally efficient manner. Here, we investigate failure-inducing critical stresses for a number of curved laminates using a higher-order beam model derived from the Hellinger–Reissner mixed variational principle, which guarantees that the hoop, interlaminar shear and radial stresses are equilibrated. By solving the governing equations of the theory in the strong form using the pseudo-spectral differential quadrature method, the model is capable of predicting accurate 3D stress fields in curved laminates, even in the vicinity of localised features such as supported edges. The model is used alongside commonly used failure criteria to reproduce experimental failure initiation results found in the literature, and the comparison suggests that failure mode, location and load are all predicted accurately. Finally, failure maps that highlight the critical stress component for failure initiation are constructed. As the thickness of the curved laminate increases, the critical stress component transitions from intralaminar hoop stress to interlaminar shear or radial stress depending on the specific laminate configuration. These findings and failure maps collectively provide insights into the mechanics of failure initiation that should also prove useful for design purposes.

Original languageEnglish
Pages (from-to)143-152
Number of pages10
JournalComposite Structures
Volume168
Early online date9 Feb 2017
DOIs
Publication statusPublished - 15 May 2017

Structured keywords

  • Bristol Composites Institute ACCIS

Keywords

  • Curved laminates
  • Higher-order modeling
  • Interlaminar stresses
  • Anisotropic materials
  • Damage onset

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