Programming the Motion of Building Façade Materials by Controlling their Latent Passive Response

Abstract

Typical motion mechanisms in adaptive skins compromise rigid kinematic mechanical systems with sensors, processors, and actuation devices, thus impeding the adoption of zero-energy buildings. This study is developing responsive low-cost adaptive building system that exploits latent properties of programmable materials, to passively respond to external stimulus. Composite programmable material “Hygromorphic Thermo-bimetals” HMTM is proposed to respond to different weather conditions, specifically Egypt. HMTM composite bilayer material is based on controlling both hygroscopic properties of wood that responds to variation in humidity and the difference in thermal coefficient of metals according to the variation in temperature. HMTM passive motion mechanism is presented as a programmable system whose bilayer motion logic is controlled through the variation in both temperature and humidity. The significance of HMTM composite is utilizing its infinite motion responses resulting from the hygroscopic properties of wood but is passively stimulated by the expansion of metal layer as the variation in temperature is the dominant factor in Egypt.