Architected Frames by Dr. Aguzzi

Frame-based lattices are lightweight structures, which are widely employed in structural engineering applications, owing to their benefits in terms of ease of fabrication and streamlined design. Only recently have these structures drawn attention for their ability to attenuate the propagation of elastic waves by behaving as frequency filters, hence paving the way for their use in mechanical vibration control.

In this work, led by Giulia Aguzzi, in collaboration with Andrea Colombi, Eleni Chatzi, Henrik Thomsen, and Aida Hejazi Nooghabi of ETH Zurich, as well as Richard Wiltshaw and Richard Craster from Imperial College London, we focus on the octet frame-based lattice and experimentally demonstrate the capability of 3D-printed architected plates, based on this geometry, to inhibit the propagation of elastic flexural waves. By leveraging the octet topology as a unit cell to design the tested prototypes, a broad and easy-to-tune bandgap is experimentally generated. The experimental outcomes are supported by extensive numerical analyses, where the influence of the modeling technique is explored in detail. In particular, the adoption of simplified models, such as the Euler-Bernoulli beam, cannot fully account for the dynamics of the octet, thus requiring further working assumptions.

Drawing from the underlying dynamic properties of the octet cell, we propose a tailorable design with enhanced filtering capabilities. We transform the geometry of the original unit cell by applying a uniaxial scaling factor that, by breaking the in-plane symmetry of the structure, yields independently tuned struts and consequently multiple tunable bandgaps within the same cell.

Our findings expand the spectrum of available numerical analyses on the octet lattice, taking it a significant step closer to its physical implementation. The ability of the octet lattice to control the propagation of flexural vibrations is significant within various applications in the mechanical and civil engineering domains; and we note such frame-like designs could lead to advancements in energy harvesting and vibration protection devices (e.g., lightweight and resonance-tunable absorbers).

Read more on this work in external page Volume 121 of Applied Physics Letters