Title: Characterization of the Performance of 3D Printed Honeycomb Cores for Resin Infused Sandwich Panels
Authors: Clement Brousse, Donald W. Radford
DOI: 10.33599/nasampe/c.23.0159
Abstract: Composite sandwich panels are used extensively to realize high flexural stiffness and reduced weight. While these sandwich structures make use of cores of various materials and geometries, honeycomb is a common choice. While seemingly simplistic in concept, the complexity required to shape the core can be difficult. Additive manufacture of the structural core has the potential to simplify the generation of complex core shapes and contours. However, before developing geometric complexity, it is necessary to better understand the relationship between the processing conditions and the mechanical properties of additively manufactured cores.In this effort, honeycomb specimens of two different cell sizes, but of a constant core density, are 3D printed from neat PETG and carbon fiber filled PETG. The reference density is based on a commercially available PET foam. Mechanical performance evaluation of the 3D printed honeycomb is carried out for the out-of-plane properties following the guidelines of ASTM C365 for compression and ASTM C273 for shear. The specimens were 3D printed using commercially available 3D printers and filaments. To avoid the process of bonding stiff plates to the core for shear testing, a novel test fixture was developed to allow the complete ASTM C273 shear test specimen to be 3D printed. The ASTM C365 compression specimens are tested in a stabilized configuration using an additional skin printed on the top and bottom of the core, to prevent crushing at the specimen extremities. In addition to serving to stabilize the structural core during testing, the thin 3D printed surfaces are meant to exclude resin from the honeycomb cells during resin infusion of composite facesheets. The influence of the manufacture on the permeability of these surface layers is evaluated during resin infusion of the sandwich panel facesheets.The results show an influence of the cell size and the reinforcement on the thermoplastic honeycomb core mechanical properties. For the best examples, the compression and shear properties exceed those of the PET baseline foam. The 3D printed surfaces proved to resist resin flow into the honeycomb during infusion. Thus, this work shows the potential for 3D printed cores for resin infused sandwich panels.
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Conference: CAMX 2023
Publication Date: 2023/10/30
SKU: TP23-0000000159
Pages: 15
Price: $30.00
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