Tensairity is a registered mark. Circle R. Tensairity is a foundational structure using inflated airbeams and attached stiffeners or cables that gains mechanical advantages for low mass. Pneumatic structures using tensairty are solving problems. [1] [2] The structure modality has been particularly developed by Mauro Pedretti. [3][4]
Bridge, band stand [5], aircraft wing construction [6]
A related structure modality is tensegrity. Conceivably, an ultralightweight structure evacuated of air would float in the atmosphere, much as a buoy floats in water A crushing load is present destabilizing such structures. However, enclosed-air structures perhaps made of tensairity beams in a tensegrity format holding an enveloping skin could be heated by solar energy and interior activity and then become lighter than air, like hot-air balloons. A torus of 72 inch major diameter and 27 inch minor diameter displaces about 5 pounds of atmosphere, so if the torus weighed less than 5 pounds, and was evacuated, it would be buoyant. Buckmister Fuller designed floating cities (air-filled) so lightweight that they would be buoyant only by the effect of solar heat warming the air within to slightly less density than the surrounding air. As domes, they were about 1/2 mile diameter. As floating spheres the cities would not experience earthquakes.
