In-situ automated fiber placement gap defects filled by fused granular fabrication

Abstract

This paper presents an investigation into the effect of Fused Granular Fabrication gap filling on the composition and mechanical performance of in-situ consolidation Automated Fiber Placement-manufactured laminates. Two laminates with staggered triangular gap defects were manufactured using in-situ consolidation Automated Fiber Placement. In the first laminate, the defects remained unmodified whereas in the second laminate Fused Granular Fabrication was used to fill the gap defects to mitigate out-of-plane waviness in subsequent plies and large pores which can initiate cracks. The process was successfully demonstrated. Fused Granular Fabrication layer thickness was however hard to adjust to match consolidated ply thickness of the AFP process due to the slightly uneven surface of the AFP substrate resulting in out-of-plane undulations. Compressive strength remained at the same level for both, reference and gap specimens. Tensile strength decreased 11 % and 23 % for gap defects and filled gap defects, respectively. Further work is required to utilize the full potential of the process combination.