Stochastic characterization of multiscale material uncertainties on the fibre-matrix interface stress state of composite variable stiffness plates

This work analyses the stochastic response of fibre and matrix scale stresses of Variable Angle Tow (VAT) laminates affected by multiscale uncertainty defects. The aim is to evaluate the influence of the innermost constituents on the overall structural response via an accurate mechanical characterization of both macro- and microscales. The Carrera Unified Formulation (CUF) is employed to obtain two-dimensional (2D) and one-dimensional (1D) models for both scales. Indeed, 2D layer-wise (LW) and 1D component-wise (CW) approaches are adopted for the macroscale and the microscale, respectively. The use of 2D and 1D models proves to be convenient as a superior computational efficiency is reached, this aspect being of great importance as many analyses are necessary for uncertainty quantification. The numerical results demonstrate the validity of the proposed methodology to obtain an accurate description of the 3D stress state at the different scales. A special focus is made on the fibre-scale stresses and how they may vary when affected by multiscale uncertainty.