Remember way back in 2010 when an epic storm bested the Metrodome in Minneapolis? An excess of snow piled up on the roof, which collapsed under the concentrated weight and broke down the Minnesota Vikings’ home (thankfully not in the middle of a game). Most similar structures are constructed with an excess of mass, or materials, put in place to offer support under the most extreme possible circumstances; these contingencies are uncommon and unpredictable, however, so it can be difficult to account for them once the building is completed. Researchers at the University of Stuttgart’s Institute for Lightweight Structures and Conceptual Design have developed Smart Shell, an almost impossibly slim prototype which uses hydraulics to adjust to real-life logistics in real time.
“The idea is to remove material that is only required very rarely, and substitute it with the temporary use of energy in the form of adaptivity,” Stefan Neuhauser explains to Co.Design. “Thus, we give the structure some ‘intelligence’ by means of being able to react to varying loading conditions to reduce the stresses in the material as well as compensate for vibrations (which easily occur in a structure this light).” The result is a four-centimeter-thick wood frame which currently arcs over 100 square meters of the college’s Valihingen campus, where it will live for the next few years as a hub for research on the subject.
One of its corners is anchored, while the other three have been outfitted with hydraulic units developed by partner Bosch Rexroth, with strategically placed sensors located on the shell itself. So how exactly does it work? Neuhauser breaks it down thusly. “The hydraulics allow us to position the supports in space, both with high speed and high accuracy. This enables us to do two things: find the optimal position of the supports so the stresses in the material are minimized (the positioning changes depending on what type of load is on the structure), and introduce very quick countermovements to compensate for and damp vibrations in the structure, reducing damage due to resonance and fatigue,” he says.
In its current state, it’s tough to imagine something like Smart Shell supporting the demands of an NFL arena, but Neuhauser states that its concepts and properties are transferable. "Large structures are what we have in mind, because here we can achieve the most weight saving," he says, and notes that even facades and bridges might also someday get the Smart Shell treatment.