LESSON 7.1 · 2:03 · CHAPTER 7 · FIBRE, RESIN AND TENSION
Every guide multiplies tension
Tension leaving a guide is the tension arriving times e^(μθ) (the capstan equation), so guides multiply rather than add: six 90° guides at μ = 0.2 multiply tension by e^(0.2·3π) ≈ 6.6. A long, bendy fibre path frays and breaks fibres.
Predict · at 0:36 in the video
Six guides, each turning the tow 90 degrees, friction 0.2. Does the tension roughly double, go up six times, or sixty?
About six and a half. Six quarter turns is three pi of wrap. 0.2 times three pi is 1.9, and e to the 1.9 is 6.6.
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 · 7.2 · 1:55How you unwind decides the twist