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8 Cards in this Set
- Front
- Back
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Consolidation due to Winding tension
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- Consolidation best at 90 degree and worst at 9 degree wind angle.
-Excess resin is squeezed out of fiber - Guard against complete loss of fiber tension - fibers in compression can buckle if resin is not gelled - this is a big issue for thick parts. |
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Methods of low angle layers onto cylindrical mandrel without tows sliding.
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Method 1: End Pins
Method 2: Geodesic path on end domes (Bottles:good, cylinders (bad) |
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In Situ Curing:
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Idea: Gel or cure material as it is deposited on mandrel
-avoid FIBER BUCKLING by limiting ungelled layer thickness - avoid EXOTHERM PROBLEMS by limiting mass of resin curing at once |
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Pot life
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Viscosity increase of 2x
Problem: Excess bath viscosity causes poor tow impregnation and fiber fraying Solution: -decrease bath temp decrease bath volume (use up resin quickly, but frequent refilling) |
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Gel time
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Material starts behaving like a solid (dip stick test)
Gel time decreases by 2x for each increment of 10 Celcius Pot life follows similar trend |
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Bandwidth Selection
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Thickness of tow = Area of wetted tow/Natural bandwith of tow
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Simple hoop pattern (Winding angle)
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alpha = arctan (bn/(pi*d))
if two overlap: then b<bn and t >tn |
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Winding parameters
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Radial accretion rate, dR/dt (cm/hr) for 1.3-cm-thick
ungelled layer: dR/dt = 1.3/(t/60) where t = gel time (minutes) • Required mandrel rotational speed, (rpm): (60) = Vf(dR/dt)L/(AN) where Vf = final fiber volume fraction L = axial length of mandrel (cm) A = area of each dry tow x-section (cm2) N = number of tows being deposited at once |
