Influence of Core Configuration on the Flexural Behavior of Lightweight CFRP Sandwich Panels in Drone Design

Sandwich structures have gained much interest in drone manufacturing structures based on their lightweight design and excellent mechanical characteristics. In this work, a new solution for lightweight drone wing structures consisting of a thin sandwich skin, a main spar, and ribs was proposed. Seven sandwich structures based on prepreg-based CFRP skins and different cores were proposed for the wing drone sandwich skin. Thus, sandwiches with different chemical configurations and densities, such as ROHACELL 51, AIREX T92.100, balsa, AIREX R82.150, AIREX C71.75, NOMEX ECA-I, and Soric XF, were autoclave-manufactured and investigated. All the samples were tested under three-point bending. Also, microscopic analysis of the fracture zones was performed to establish a direct link between macroscopic flexural behavior and local failure mechanisms. A statistical analysis based on ANOVA with Box-Cox transformation followed by Tukey's Honestly Significant Difference test was performed for flexural strength and flexural modulus. The results show that the sandwiches containing Soric XF foam with 62.5 kg/m³ density had the best mechanical properties, with a 71.66 MPa flexural strength and a 10,039 MPa flexural modulus.