Konstantinos Zafeiridis, Numerical prediction of the compressive behavior of pultruded carbon fiber profiles for wind turbine blades, Master Project

Activity: Examinations and supervisionSupervisor activities


Carbon fibre reinforced pultruded profiles are characterized by their exceptional mechanical properties. Their superiority against composites fabricated with different manufacturing techniques is favourable when they are intended to be used as main loading carrying components at the spar caps of wind turbine blades. Their very few defects render difficult and doubtful the determination of their behaviour when they are tested under compression.

Two and three-dimension numerical models are employed for predicting the compressive behaviour and validating experimental results from two specific pultruded profiles, named S and Z profile. Their material properties needed as input for the numerical models are determined and simulations considering different material systems and fibre orientations are conducted as a parametric study for the compressive strength and stiffness predicted from the models. Furthermore, the impact of the resin properties, the temperature, the element size, and the different fibre imperfection assumed in the numerical models on the compressive behaviour of the composites are also investigated. Additionally, a comparison between the 2D and 3D user material subroutines (UMAT) is performed, showing how the plane strain condition is handled by each model.

The numerical predictions are in good agreement with the experimental results. The Z pultruded profile performed better compared with the S profile, by showing higher strength both when it is mechanically tested and numerically simulated. Finally, the inferior tensile matrix properties caused by elevated temperatures and generally low-performance resins, and the level of the fibre misalignment are the primary parameters that undermine considerably the performance of the pultruded profiles under compression.
Period15 Jan 202115 Jun 2021