LESSON 1.1 · 3:20 · CHAPTER 1 · WHY WINDING
Why pipes split lengthwise
In a closed tube under pressure, the stress around the tube (hoop) is twice the stress along it (axial). That is why pipes split along their length, why a metal wall wastes half its strength in one direction, and why it pays to place fibre exactly where the load is.
Predict · at 1:10 in the video
Now cut it across instead, so the end cap wants to fly off. Is the stress along the tube bigger than P R over t, the same, or smaller?
Smaller. Exactly half. The end cap feels the pressure over its whole area: pi R squared.
Further reading
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
About the numbers
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.
Up next · 1.2 · 3:38The factor of three