Kinetic module in bimetal: A biomimetic approach adapting the kinetic behavior of bimetal for adaptive Façades

Abstract

This research is bioinspired by the leaf-rolling mechanism observed in Ammophila arenaria grass. This organism exhibits a bending behavior in response to adverse environmental conditions. We used bimetal, a smart material composed of two layers with distinct expansion coefficients, providing a bending behavior triggered by heat, mimicking the organism's natural response. Following the A. arenaria’s morphology, we applied creases on the bimetal's active layer. These creases influence the movement behavior of the bimetal, causing it to open when heated and close when cooled (opposite to the behavior observed in the material without creases). This study focuses on investigating the behavior of creases on the bimetal to propose a kinetic façade module responsive to changes in environmental temperature — the Bimetal Biomodule. We conducted exploratory studies to introduce creases on the bimetal surface, employing both handmade creases and 3D-printed matrix for stamping. We evaluated the response of the biomodule samples to temperature variations. Our findings indicate that interspersed creasing patterns, associated with the absence of creases at the material edges, influence the bimetal's behavior, offering control over material responsiveness beyond its properties. Prototypes and tests demonstrated the biomodules’ potential for self-shading applications on façades without electrical power or any mechanical device.