Design it to fail in the hoops
The stress ratio, helical fibre stress over hoop fibre stress at burst, decides where a vessel fails and how predictably. Below one the hoops are the weak link: the vessel splits along the cylinder with tight scatter. Near one, the failure location is a coin toss; above one, the domes go first and the scatter grows.
Predict · at 1:00 in the video
Three designs: stress ratio 0.75, 0.95, and 1.1. Which one gives the tightest spread of burst pressures?
0.75. Every one of the fifty fails in the hoops, and the burst pressures spread by about 4 percent. At 0.95 it's a coin toss: about a third fail in the domes, and you can't say in advance which.
This course is our own. These books go deeper.
- Composite Filament Winding, S. T. Peters (ed.), ASM International, 2011
- Filament Winding: a Unified Approach, S. Koussios, Delft University Press, 2004
Simulations in this lesson are our own. Where a number rests on an assumption, the video marks it with an asterisk and says where it comes from.
