Abstract
Additive manufacturing (AM) is increasingly used for on-demand spare parts and small series of end-use parts. AM processes have many advantages, such as enabling innovative designs with short lead times. AM technologies, including process monitoring systems, are developing at a fast pace.
This study deals with material-extrusion AM with continuous-fibre reinforcement in a thermoplastic polymer matrix (CFAM). Parts produced by CFAM are typically composed of two phases: one phase dominated by continuous fibres and one only reinforced with short fibres. Consequently, the study also assesses the short fibre phase and the interfaces between phases.
A key challenge regarding CFAM processes is to understand their capabilities and limitations compared to conventional composite manufacturing processes, including process‑specific defects and failure modes, such as delamination. To predict the mechanical performance of parts made by CFAM, there is a need for material models and data for numerical simulations. For rapid on-demand production of critical parts there is no time for trial and error and design iterations.
An R&D project in our lab aims to establish a comprehensive framework, combining experiments and modelling, in order to predict and optimize CFAM part performance. Options for material recycling are also studied. Some results from this work will be presented.
The presentation will focus on quasi-static loading of the two material phases (short and continuous fiber-reinforced thermoplastics) and their interfaces, and the calibration and verification of material models. The continuous fibre phase was tested assuming transverse isotropy to determine the material parameters for tension, compression and shear. A second set of experiments determined the interlaminar shear properties for the laminate response. Testing the short fibre phase captured the nonlinear material behaviour to failure in tension, compression and shear. A final set of experiments captured mode-I traction-separation data for the inter- and intralaminar interfaces of the continuous fibre phase.