Impact damage modelling in composite laminates – numerical implementation of a strain rate dependent damage model

  • Ivančević, Darko (University of Zagreb, Faculty of Mechanical E)
  • Ratković, Jakov (University of Zagreb, Faculty of Mechanical E)

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In this work, a numerical methodology for simulation of impact damage in laminated CFRP structures has been developed and implemented into the Abaqus/Explicit software. The methodology is based on the recent insights into the mechanical behaviour of CFRP materials at various strain rates. Failure initiation is modelled using the phenomenological failure theory that was introduced in [1]. The model is based on the well-known theories introduced in [2,3] that have been modified to include the strain rate effects that influence the failure processes driven by the matrix dominated properties. The failure processes of the matrix failure modes in the model are simulated in the fracture plane using a Continuum Damage Mechanics framework based on the approach introduced in [4]. This approach has been modified to include the strain rate effects and to account for the mesh objectivity of the damage process in this work. The model has been implemented into Abaqus/Explicit using the user-material subroutine VUMAT and details of the implementation are discussed in the work. Validation of the failure initiation process at increased loading rates has been performed by comparison with the experimentally observed bi-axial failure curves of the IM7/8552 and AS4/3501-6 CFRP materials at various strain rates. The model has been applied to simulation of the low and high-velocity impact problems demonstrating that the damage modes of the composite plate, as well as the contact forces, have been simulated accurately. The methodology is currently focused on application in unidirectional composite plates, but woven composites will be investigated in the following research phase. Additionally, only in-plane failure modes are currently considered whereas the out-of-plane damage modes will be investigated in the subsequent research. The research is fully funded by the Croatian Science Foundation (HRZZ) within the project “Computational Modelling of Composite Structures Impact Damage” (CONCORDE), grant number UIP-HRZZ-2020-02-9317.