What If Building Skins Resembled Human Skin?

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Breathable and self-sustaining, there is no façade more dynamic than the “first” skin — our own. And so, what if building skins moved toward intentionally mirroring human skin? Imaginative biologist-turned-architect Doris Kim Sung is urging designers to think about thermobimetal, an experimental alloy with the unique ability to move and expand when heated.

In Sung’s world of biomimicry and “smart,” moving metal façades, buildings would automatically respond to changes in their environment. Just imagine if buildings possessed natural molecular functions similar to the everyday human action of sweating to cool off. Leveraging edge from her interdisciplinary background, when Sung first launched the material into the architecture world’s purview, it had no previous applications. Absent from the minds of architects but common throughout other trades, thermobimetal is a steadfast sheet metal found in household thermostats.

When thermobimetal is heated, it naturally curls into a C-shape resembling a human eyelash; video via The Creators Project.

So how does it work? The material is composed of two alloys that are layered on top of one another. With different coefficients of expansion, one side expands more than the other when heated. At first, the material will start to pivot at about 70 degrees Fahrenheit, but with sustained heat application, it can continue contracting up to about 400 degrees Fahrenheit. The result is a dynamic eyelash-like curl.

Beginning in 2010, Sung has stitched together several prototypes that focus on discovering and harnessing the potential of thermobimetals’ various qualities. Each project grows more ambitious and comprehensive than the last. Inaugurated with a pioneering project that explicitly mimicked the human body’s curves, “Waist Tightening” displayed a preliminary focus on how exactly the material would change with temperature and heat application.

Waist Tightening morphs to resemble a cinched waist when heated; image via dOSu-Arch.com.

Sung followed up on these discoveries with Bloom. Launched in 2012, the installation experimented with the material’s reaction under natural sunlight and heat radiation. Composed of 14,000 smart thermobimetal tiles, she found that each piece automatically curled when the outdoor temperature rose about 70 degrees Fahrenheit.

With the advent of Bloom, Sung had successfully demonstrated two major goals: Thermobimetal could perform as a sun-shading device and a ventilation system, thus boasting some features similar to artificial air conditioning. Now what? With each step of her research and work, Sung seeks to inspire a radical new way of imagining the built world. She argues that a building’s aesthetic components must no longer be determined by what we think they should look like; she adamantly reminds us that a house does not need to be confined to the archetypal form we played with in Monopoly as children.

Bloom by dOSu-Arch.com; image via ArchDaily

Self-identified as a “bottom-up” practitioner, Sung expresses her deep admiration for aeronautical engineer Paul MacCready, who insisted that inventing seemingly impractical objects is critically important, as they can spawn fascinating and novel ways of imagining the world. While this may be the case, Sung’s work is neither impractical nor merely sculptural. Humility aside, it is revolutionary and ever-changing.

Over time, Sung’s research has metamorphosed into a structural system that is beneficial from cradle to grave. For EXO Structural Tower, dO|SU STUDIO ARCHITECTURE partnered with Arup Engineering and fabricators Neal Feay Co. and Engineered Materials Solutions. With a fastener-free construction process, the project showed how the “smart” natural curl of thermobimetal could enable a person to assemble the surface with a single hand, with no mechanical force and minimal effort and danger.

Composed of nickel, iron and manganese, each piece was heated at 350 degrees Fahrenheit until an optimal geometric curl was achieved. Once the eyelash-like curl was perfected, the structure was cooled into its final state. When complete, the material shell proved to be extremely strong and lightweight, resembling the exoskeleton of a lobster or crustacean.

Left: Thermobimetal pieces laser-cut and numbered for easy assembly; right: EXO Structural Tower demonstrates just one layer of what could one day grow into a full-size skyscraper; images via Architecture Magazine.

Sung’s responsive design serves as a strong call to action; these are the types of materials that we need to be producing. In “Buildings That Breathe,” Sung states that “over time, I’ve moved more towards the technology side of architecture and realized that I had to compete in the world of building technology.” While it is both bold and terrifying to postulate that we have been building things wrong, Sung delves into such an arena without hesitation.

As a researcher whose work remains deeply grounded in science, Sung is indispensable to the architecture community. By merging art with technology and aesthetics with engineering, Sung has forged an architectural approach that offers sympathetic answers to some of today’s most salient design problems. What if, all along, architects should have been taking more investigative cues from the natural functions within their own bodies?

Sung’s research should inspire architects to look at everyday materials in a whole new light.

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