Design, manufacturing and testing of 3D printed variable-stiffness laminates for improved open-hole tensile behaviour

Authors

Iragi M., Pascual-González C., Esnaola A., Morales U., Aurrekoetxea J., Lopes C.S., Aretxabaleta L.

Reference

Additive Manufacturing, vol. 63, art. no. 103418, 2023

Description

Using 3D printing, continuous fibre can be steered in high curvature paths to create variable-stiffness (VS) laminates for applications such as notched laminates. In the present study, VS 3D printed continuous carbon fibre-reinforced thermoplastic laminates were designed, manufactured, and tested, to improve open-hole tensile behaviour. The design was carried out taking into account the current limitations of fused filament fabrication. A curvilinear function was used to describe the fibre trajectory of the VS laminates, which enabled the parametrisation of the design-oriented meso-scale model based on the finite element method. Conventional stress-based models for the estimation of damage initiation and ultimate failure strengths were adapted to the behaviour of the 3D printed material. These models successfully reproduced the fibre-dominated behaviour of the printed laminate. An as-manufactured model was also developed to analyse the effect of defects caused by manufacturing constraints. VS laminates presented higher strength than quasi-isotropic reference laminates for holes larger than ∅1mm, increasing to more than 30% for holes of ∅6mm or larger. In addition, this increase in strength combined with the slight decrease in stiffness significantly increased the energy absorbed up to failure (up to 200%).

Link

doi:10.1016/j.addma.2023.103418