This set of Composite Materials Multiple Choice Questions & Answers (MCQs) focuses on “Filament Winding”.
1. In a filament-winding process, axisymmetric hollow parts are produced by wrapping monofilaments around a rotating mandrel and curing it.
a) True
b) False
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Explanation: Filament winding mainly involves the manufacturing of cylinders and tanks. The applications of filament winding are helicopter blades, automotive drive shafts, pipelines, oxygen tanks, large underground gasoline storage tanks, spherical pressure vessels and conical rocket motor cases.
2. Which process is used for manufacturing XMC?
a) Pultrusion
b) Compression molding
c) Filament winding
d) Vacuum bag molding
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Explanation: One of the important application of the filament-winding process is the production of prepreg sheets or continuous fiber-reinforced sheet-molding compounds like XMC. The sheets are produced by slitting the wound shape parallel to the mandrel axis.
3. What is used to control the fiber tension in the filament winding process?
a) Fiber creels
b) Mandrels
c) Fiber guides
d) Preformers
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Explanation: Fiber guides or scissor bars located between each creel and the resin bath in the filament winding operation is used to control the fiber tension. The fiber tension is an important process parameter since adequate fiber tension is required to maintain fiber alignment.
4. ____________ controls the resin coating thickness around each roving and removes the excess resin from the rovings.
a) Wiping device
b) Scissor bars
c) Mandrels
d) Fiber creels
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Explanation: In the filament winding operation, the wiping device is placed at the end of the resin tank. A set of squeeze rollers is the most commonly used wiping device in which the position of the upper roller is adjusted to control the resin content and the fiber tension.
5. Pulling each roving separately through an orifice is an alternative way for wiping the resin-impregnated rovings in the filament winding process.
a) True
b) False
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Explanation: This technique provides better control of resin content compared to the wiping device technique. But the probability of the fiber breakage increases and it becomes difficult to rethread the broken roving line through its orifice.
6. The angle of the roving band with respect to the mandrel axis is called __________
a) band angle
b) roving angle
c) wind angle
d) mandrel angle
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Explanation: Wind angles can be adjusted anywhere between near 0° to near 90° by changing mandrel’s rotational speed and carraige feed rate. The wind angle affects the mechanical property of the material.
7. In ______________, the carriage rotates about the longitudinal axis of a stationary mandrel.
a) polar winding
b) helical winding
c) hoop winding
d) circumferential winding
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Explanation: In polar winding after each rotation of the carriage the mandrel is indexed to advance one fiber bandwidth. There are no fiber crossovers since the fiber bands lie adjacent to each other. Polar winding process requires mandrel end fiber winding.
8. Hemispherical domes with central openings are commonly used at the mandrel end for manufacturing pressure vessels.
a) True
b) False
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Explanation: Pins or rounded edges at the mandrel ends are used for manufacturing open-ended products, such as a pipe or a drive shaft. The central openings are necessary to extract the mandrel from the cured pressure vessel.
9. Which is not a factor affecting the fiber wet-out?
a) The viscosity of the resin
b) Speed of winding
c) Fiber tension
d) Fiber density
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Explanation: Good fiber wet-out is essential for reducing voids in a filament-wound part. There are many factors influencing fiber wet-out. The viscosity of the catalyzed resin in the resin bath depends on the resin type and resin bath temperature. The fiber tension controls the pressure on various layers wound around the mandrel and the winding speed influences the fiber wet-out by varying contact time with the resin.
10. Adequate fiber tension is required to maintain fiber alignment on the mandrel as well as to control the resin content in the filament-wound part.
a) True
b) False
View Answer
Explanation: Fiber tension should be kept optimum since it affects the filament winding process. Excessive fiber tension will lead to undesirable residual stresses in the finished product, variations in resin content in the inner and outer layers and huge mandrel deflections. Fiber tension is produced by pulling the rovings through fiber guides placed between the resin bath and the creels.
11. Which is not a reason for the appearance of voids in filament wounded parts?
a) Poor fiber wet-out
b) Winding speed
c) Presence of air bubbles in the resin
d) Improper bandwidth
View Answer
Explanation: The common defects in filament-wound parts are and fiber wrinkles, voids and delaminations. Voids may appear because of the presence of air bubbles in the resin bath, by poor fiber wet-out and gapping or overlapping resulting from improper bandwidth.
Sanfoundry Global Education & Learning Series – Composite Materials.
To practice all areas of Composite Materials, here is complete set of 1000+ Multiple Choice Questions and Answers.
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