Vibration behavior of hybrid sandwich beams with TPU lattice cores and carbon fiber face sheets

This study investigates the vibration behavior of hybrid sandwich beams composed of thermoplastic polyurethane (TPU) lattice cores and carbon fiber reinforced polyamide face sheets. Ten different strut-based lattice topologies were designed with approximately constant mass to evaluate the effect of geometry on dynamic response. Experimental modal analysis was conducted under cantilever boundary conditions to determine the fundamental natural frequencies and damping ratios. The results indicate that lattice topology plays a critical role in governing stiffness and damping characteristics. Configurations with higher connectivity exhibit increased stiffness, while structures allowing greater deformation show enhanced damping characteristics. An inverse relationship between stiffness and damping is consistently observed across the investigated designs. These findings highlight the potential of geometry-driven design in tailoring the dynamic performance of lattice-based sandwich structures, and provide insights for the development of lightweight metamaterial-inspired systems with application-specific vibration characteristics.