The Development of a 3D-Printed Compliant System for the Orientation of Payloads on Small Satellites: Material Characterization and Finite Element Analysis of 3D-Printed Polyetherketoneketone (PEKK)

Abstract

This article focuses on the development of a 3D-printed 2-degree-of-freedom (DOF) joint for the payloads’ orientation on small satellites. This system is a compliant mechanism, meaning that this monolithic system composed of cross-axis flexural pivots (CAFPs) produces complex movements through the elastic deformation of its structure. Using fused filament fabrication (FFF), a demonstrator made of Polyetherketoneketone (PEKK) is printed to determine its potential compatibility with space conditions. Focusing on a segment of the joint, the CAFP, this study aims for an enhancement of its mechanical behavior through the study of its printing direction and the creation of an accurate finite element model of this compliant mechanism. First, material characterization of 3D-printed PEKK is achieved through differential scanning calorimetry tests of the filament and flexural and tensile tests of specimens printed in different printing directions. Then, these data are used to perform a finite element analysis of different CAFP designs and compare their mechanical response of their 3D-printed twin using digital image correlation software. Finally, the CAFP structures were observed by X-ray tomography. The results show that printing direction greatly influences both flexural and tensile strength. Voids induced by the FFF process could impact the mechanical behavior of 3D-printed parts as the simple CAFP design has a better test/model correlation than complex ones. This could influence its resistance to space environment.