Effect of tailored fiber deposition in 3D printed composites: application of an anisotropic phase field model

Abstract

Continuous Fiber 3D printing is a relatively new technology which can allow for tailored reinforcement of critical regions in structural components, i.e., stress concentrations, following principal stress lines. The influence the fiber deposition path has on the mechanical and failure behavior of such components is assessed using an anisotropic phase field model. A comparison with experimental results for notched unidirectional composite plates, available in the literature, demonstrates the ability of the method to produce satisfactory predictions for unidirectional reinforcement paths. The analysis is then extended to Open-Hole and Double Edge-Notched tension coupons of both unidirectional and variable stiffness reinforcement patterns. It is observed that the strength obtained for the components made with a reinforcement pattern that follows the principal stress lines is markedly higher than that for the equivalent unidirectionally reinforced ones. It is highlighted that the improvement in strength deriving from the tailored fiber deposition cannot be deduced solely by the analysis of the stress concentration factor but an analysis taking damage into account is necessary. In addition, the effect of the reinforcement strategy on the size effect was also explored, highlighting how the tailored fiber path leads to an increase in the failure load attainable by the specimens for all the dimensions analyzed.