Anna Lutz, “Strength Analysis of Additively Manufactured Sandwich Composite Inserts”
Mentor: Rani El Hajjar, Civil & Environmental Engineering
Poster #168

The central goal of this research project is to design an additive manufacturing insert for composite materials with high strength and load capabilities. Sandwich composite materials are, as the name suggests, layered, high-strength materials that are sandwiched together. The top and bottom layers are carbon-fiber reinforced sheets, and the center layer is an aluminum honeycomb structure. Due to its lightweight components, sandwich composite structures have one of the highest strength-to-weight ratios of any material. However, due to the thin walls within the honeycomb structure, it is not possible to directly thread fasteners through the material while maintaining strength integrity. This introduces the problem of integrating mechanical connections, which is why inserts are a crucial component during the manufacturing process. Inserts are anchors that allow fasteners, like screws and bolts, to be threaded through the composite material for attachment to other components. For the aim of this project, multiple iterations of inserts were designed with CAD software to be 3D printed using a high-temperature thermoplastic material. Once the panels were fabricated, a compression test was performed on both the 3D printed inserts and the industry-accepted aluminum inserts, to collect strength data on the specimen. These results were compared to theoretical models using finite element analysis, which was the computational tool used to simulate the stress distributions on the inserts during loading. The designed additive-manufacturing insert showed improvements in maximum force, stiffness, and energy absorption, as well as fabrication time, when compared to the standard aluminum insert. The finite element analysis accurately predicted the stresses on the inserts under loading, further confirming the results of the compression test. Sandwich composite materials are utilized in various fields, such as aerospace, automotive, and biomedical industries. Continuing the research and development of composite inserts allows for a wider range of applications for sandwich composite materials.