Was there not an experimental bike frame built that was highly pressurized (nitrogen) to increase its rigidity?
I know they do this with helicopter rotor blades, as a crack-detection method, and the infafous Porsche 917 racer had an aluminum tube space frame that was also pressurized only to detect cracks.
The theory is that under internal pressure any tube frame would be far more rigid than otherwise. Does anyone know what work has been done on this admittedly "odd" notion?
Dear Brafield:
Rigid is not the problem, ultimate tensile strength is the problem. Being built to withstand high internal pressure plus load, takes more weight than just bearing the load.
They pressurize aircraft upon takeoff, (among the many reasons) to minimize fatigue on the aluminum as it flexes upon takeoff and establishment of the various boundary "structures".
Its not that odd, really... if you had a circumstance, say shock absorbers on heavy trucks where they were always under compression, internal pressure is a very good thing.
David A. Smith
Thank you. Yes, and it since occurred to me that internal pressure would act unevenly along a tube, trying to "balloon" at the centre and less so at the closed or reinforced ends.
There goes another bright idea!
Probably not as bad as you imagine...
Don't give up this easy. Imagine a car that was just one big air bag...
i think increasing the thickness of the tube is better compensated by increasing the internal pressure by means of a gas.
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