Structural cohesive element for the modelling of delamination between thin shells without cohesive zone limit

  • Ai, Xiaopeng (TU Delft)
  • Chen, Boyang (TU Delft)
  • Kassapoglou, Christos (TU Delft)

In session: - Delamination I

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Delamination is a critical mode of failure that occurs between layers in a composite laminate. The cohesive element is a widely-used interface element based on the cohesive zone model for modeling delamination. However, cohesive elements suffer from a well-known limit on the mesh density – the element size must be much smaller than the cohesive zone size. Based on the earlier work in 2D [1] and in 3D (for Mode I only) [2], this work develops a new set of structural elements, where the plies and interfaces would be modelled with C1-continous triangular Kirchhoff-Love shell elements and conforming cohesive elements, respectively. The triangular shape is chosen for its flexibility of modelling arbitrary (sub-)domain geometries. No curvature degree of freedom is needed as opposed to the case in [2]. The proposed method is verified and validated on the classical benchmark problems of Mode I, Mode II and mixed-mode delamination [3]. All the results show that the size of elements can be at least 2 times larger than the cohesive zone length while retaining accuracy. This would then allow the accurate modelling of delamination without worrying about the cohesive zone limit on mesh density. Therefore, a lot of computing time can be saved by the proposed method.