Morphing Tensile Structure
What if you could change the shape of a tensile structure according to the natural loads, such as wind forces, it experiences? In exploring this question researchers at the University of Stuttgart and the company Bosch Rexroth came up with a tensile canopy (membrane) - nothing new there. However, their novel design uses a feedback system driven by a sensor array connected to hydraulic rams that apply counter forces to natural loads.
Image courtesy of Bosch Rexroth
The traditional design approach for static structures is to ensure the structure is capable of withstanding a brief extreme wind gust. The design is then fixed for all time to withstand this rare extreme condition.
The experimental structure designed by the researchers is a four point wooden canopy that spans 100 m2 and is 40 mm thick. With their morphing design they claim that the structure can be lighter than traditional fixed structures, because it can reduce peak stresses by subtle shape changes.
A key element of the research was the design of the control system rules to direct the hydraulic rams in response to the sensor array. Both static and dynamic natural loads were simulated in order to determine how best to apply counter forces. These control rules are encoded in the active system, which responds in real-time to the natural loads applied.
The project is still in the evaluation stage, but it holds the promise of providing designers with another technique to design structures to withstand the rigors of nature.