Investigation of Mechanical Properties of Composites-Based Sheet Lamination Additive Manufacturing Process

Abstract

The Composites-Based Additive Manufacturing (CBAM) system is a novel sheet lamination process combining mats of randomly oriented carbon fiber (CF) reinforcement with thermoplastic matrix materials to fabricate composite objects. This study investigated the suitability of three ASTM test standards for tensile, inplane shear, and interlaminar fracture properties of two CBAM material systems: CF reinforced Nylon-12 (CF/PA12) and CF reinforced polyether ether ketone (CF/PEEK). The tensile, in-plane shear, and interlaminar fracture tests were well suited for the CF/PEEK material, though high variability was found in the interlaminar fracture response. The CF/PA12 material system exhibited high plasticity and evidence of a poor fiber-matrix interface. This was shown by fiber pullout in the tensile tests and the presence of voids observed on the in-plane shear surfaces. The interlaminar fracture test method was invalid for the CF/PA12 material due to a large process zone invalidating. These results show CF/PEEK to be a promising material system for the CBAM process while CF/PA12 requires further development.