COMPOSITES 2025

Intralaminar Failure of Laminated Composites Modelled by Continuum Damage Mechanics Combined with Computationally Efficient Homogenisation

  • Hertelendy, Krisztián (Chalmers University of Technology)
  • Larsson, Ragnar (Chalmers University of Technology)
  • Gutkin, Renaud (Volvo Car Corporation)

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To increase the use of polymer structural composites, a major problem is properly accounting for intralaminar failure mechanisms such as fibre kinking caused under compression. Fibre kinking is triggered by the initial misalignment of the fibres with respect to the compressive force. Due to this mismatch between the load and the reinforcing fibres shear stresses arise in the matrix. The nonlinear nature of the composite's shear curve leads to increasingly bent fibres in a kink-band until the lock-up angle is reached. To account for fibre kinking failure, the authors of [1] use a continuum damage mechanics approach in a large strain setting. The constitutive relations are applied at the ply level, where the initial misalignment of the fibre is incorporated through an RVE of a simplified fibre-matrix mixture. The degradation of the composite is modelled on the homogenised fibre-matrix response of the RVE. In this contribution, we advance the developments in [1] by focusing on a rotation neutralised formulation for the homogenised response of the composite, independent of the rigid body rotation of the fibres. Furthermore, by introducing an RVE consisting of two constituents (matrix and fibres), failure can be modelled as material degradation concentrated in the matrix. The recovered finite rotation calculated from the deformation gradient is considered as the average fibre rotation in the element. A parameter identification process is carried out for a T700/epoxy composite material based on available test results and general values reported in the literature. After parameter calibration, the presented model is used to predict the response of three different laminated composite coupons made of UD, NCF and twill plies of the same material in 0° and 45° compression tests. The predicting capability is compared against other well-established models from the literature [2], [3] using the same experimental results. All models are implemented in Abaqus as VUMAT subroutines, and a cohesive zone model is used for modelling delamination. References [1] - R. Larsson et al. Compressive failure and kink-band formation modeling, European Journal of Mechanics - A/Solids, Volume 99, 2023. [2] - M. Herraez et al. Modeling Fiber Kinking at the Microscale and Mesoscale, 2018. [3] - S.T. Pinho, et al. Physically-based failure models and criteria for laminated fibre-reinforced composites with emphasis on fibre kinking: Part I: Development, 2006. Composites Part A.