Interplay Between Acoustical and Mechanical Properties in Lattice Structures: A Geometrical Perspective

The imperative for lattice structures to excel in both sound absorption and mechanical properties arises from the increasing demand for materials and structures that offer multifunctional solutions. However, the relationship between these two properties, and on how to design structures that excel in both, remains uncertain. Here, a perspective is presented on the interplay between sound absorption and mechanical properties in lattice structures, focusing on their mechanisms, limitations, and recommendations. First, a new term acoustical geometry is introduced to describe the features influencing sound absorption in lattice structures. Identified from the absorption resonance's structural requirements, acoustical geometries are derived from the actual lattices’ structural features. Using this, links between sound absorption and mechanical properties are drawn. It is found that truss and triply periodic minimal surface lattices lack the design freedom needed to simultaneously customize sound absorption and mechanical properties, as both are inherently tied to the same structure. For the inherent capability of introducing pores strategically, this relationship is less intertwined for plate lattices. Therefore, it is advocated for the development of hybrid lattices with features that decouple sound absorption from mechanical properties, paving the way for new meta materials that enable customizable multifunctionality.