Enhancing Strength of Nomex Sandwich Structures through the Utilization of Nano Clay Dispersed Epoxy Resin: A Study in Aerospace Applications

Abstract

Nomex sandwich structures are highly preferred in aerospace applications for their combination of lightweight and robust design. These panels feature Nomex honeycomb cores sandwiched between composite face sheets, usually made of CFRP or fiberglass, providing outstanding strength-to-weight ratios. The heat-resistant properties of Nomex enhance their suitability for aerospace environments, maintaining structural integrity even under high temperatures. These structures find application in aircraft fuselages, wings, and interior components, enhancing performance while minimizing weight. In this study, the effect of dispersing 30B nano clay in epoxy resin on the shear strength and flexural strength of Nomex honeycomb sandwich panels with CFRP skins and Nomex cores was investigated. Initially, 30B nano clay was dispersed in epoxy resin using two methods: ultrasonic mixing and high-speed stirrer, at weight percentages of 0.5%, 1%, 3%, and 5%. Then, three-point bending specimens were fabricated to assess interlaminar shear strength, fracture toughness, and flexural strength. Adding nano clay to the epoxy resin resulted in increased fracture toughness, with the highest toughness achieved at 1% weight percentage in both mixing methods. Moreover, nano clay increased the interlaminar shear strength, particularly with a carbon substrate. However, due to reduced adhesion between the substrate and resin, the interlaminar shear strength decreased compared to pure resin. The flexural strength results showed that adding a resin layer to the sandwich specimen increased strength and flexural modulus by up to 20%.