Multifunctional design of triangular lattice metamaterials with customizable thermal expansion and tunable bandgap properties

New approaches for realizing multifunctional research and tunable properties of materials are proposed by designing lattice metamaterials. In this study, the finite element method is used to study the bandgaps of the joint-bonded triangular cell lattice metamaterial. A new multifunctional design method is proposed for designing metamaterials with tunable bandgaps and specific thermal expansion properties. In this method, the geometric deformation characteristics of thermal expansion of materials are studied, and a design method for maximum bandgaps’ tunability under the condition of a specific coefficient of thermal expansion is proposed to realize the tuning of bandgaps’ characteristics based on external temperature change. Numerical results show that the proposed method and metamaterials can demonstrate significant tunability of bandgaps. This finding provides a common method for designing bandgaps’ tunable acoustic metamaterial systems, which have broad application potential under variable temperature loading and can be extended to other topological structures.