Buckling pressure of “pumpkin” balloons

Computation of Buckling Pressure of Pumpkin Balloons

This paper is concerned with the elastic buckling of pumpkin-shaped balloon structures. Pumpkin balloons, currently being used in the NASA Ultra-Long Duration Ballooning (ULDB) Program, consist of stiff meridional tendons that constrain a thin, highly curved plastic surface. The present study exploits the high degree of symmetry of this design by adopting a newly developed, closed form expressi...

Shape Optimization of “Pumpkin” Balloons

This paper is concerned with the optimization of the cutting pattern for the lobes of pumpkin-shaped balloon structures. Pumpkin balloons, currently developed for the NASA Ultra-Long Duration Balloon (ULDB), consist of stiff meridional tendons that constrain a thin plastic film. The present study shows that the maximum stability of pumpkin balloons is reached if their surface area is minimized ...

Viscoelastic behaviour of pumpkin balloons

The lobes of the NASA ULDB pumpkin-shaped super-pressure balloons are made of a thin polymeric film that shows considerable time-dependent behaviour. A nonlinear viscoelastic model based on experimental measurements has been recently established for this film. This paper presents a simulation of the viscoelastic behaviour of ULDB balloons with the finite element software ABAQUS. First, the stan...

Evaluation of Buckling and Post Buckling of Variable Thickness Shell Subjected to External Hydrostatic Pressure

Buckling and post buckling of cylindrical shells under hydrostatic pressure is regarded as important issue in structure of submarines. These cylindrical shells have variable thickness due to construction process which effected by pressure of buckling and its destruction. In this paper, effects of changing thickness on buckling and destruction pressure under external hydrostatic pressure of a sh...

A Technique to Predict Clefting of Lobed Super-Pressure Balloons