Concave shapes bridge
A fibre under tension stays on a surface only where the normal curvature along it is positive. On a waist the surface is convex around and concave along, so low-angle fibres feel the concave side and lift off, bridging the hollow. For a 100 mm waist whose profile curves at 200 mm, fibres below about 35° bridge.
Predict · at 0:44 in the video
Can you wind an hourglass waist at 15 degrees?
No. Take a waist 100 millimetres in radius, whose profile curves at 200 millimetres. Below about 35 degrees from the axis, the concave side wins, and the fibre lifts off and bridges the hollow.
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.
