Static and fatigue testing of open-hole and assembled composites based on long carbon fiber and a nylon matrix developed using fused deposition modelling: Multiscale characterization of printed holes and machined holes

Abstract

The three-dimensional printing of long fiber composites was developed in recent years, and the mechanical behavior of the printed composites requires further investigation. The joining of this type of material requires a hole; and with reference to the available literature, the bearing strength requires investigation. In this context, three manufacturing processes were used for hole generation: direct printing, conventional drilling, and abrasive waterjet drilling (AWJ). The holes obtained by these manufacturing processes were characterized using X-ray tomography and a roughness system. Open-hole quasi-static and fatigue tests were used to assess the mechanical behavior of hole manufacturing on the tensile sections. Single-shear bearing tests yielded the same trend as that observed with open holes, where conventional drilling demonstrated higher performance than the printed and AWJ specimens. The absence of delamination and higher drilling temperature sealed the surface, thus limiting the influence of voids.