Author Question: You have been asked to manufacture a wiring junction box for connecting electrical wires in a ... (Read 36 times)

nelaaney

  • Hero Member
  • *****
  • Posts: 560
You have been asked to manufacture a wiring junction box for connecting electrical wires in a fighter aircraft. The box sits under the pilot's seat and is part of the seat ejection system. Sufficient forces are exerted on the box that it must be made of a composite material using intermediate to long fibers. What fiber, matrix, and manufacturing method would you use for this part, and why?
 
  What will be an ideal response?

Question 2

Why does crosslinking increase the environmental stress-crack resistance of polymers?
 
  What will be an ideal response?



tjayeee

  • Sr. Member
  • ****
  • Posts: 329
Answer to Question 1

Several materials could be chosen but, because of its good electrical and heat insulative capability and its non-flammable nature, phenolic seems to be the appropriate resin. The fibers need to be strong, stiff, and tough enough to withstand the ejection impact. Therefore, aramid is a good choice for the fibers. The manufacturing process could be either compression molding or RTM, probably depending upon whether the fibers need to be longer than those that could conveniently be used in compression molding.

Answer to Question 2

Environmental stress-cracking is seen in polymers that have high internal orientation, such as extruded polyethylene tubing which has had a high drawdown. The polymer molecules are aligned in such cases and are stressed. When the environmental effects act on these polymers, cracking occurs. By crosslinking the polymers, the chains are held together and cracking is prevented.



Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
 

Did you know?

Of the estimated 2 million heroin users in the United States, 600,000–800,000 are considered hardcore addicts. Heroin addiction is considered to be one of the hardest addictions to recover from.

Did you know?

Tobacco depletes the body of vitamins A, C, and E, which can result in any of the following: dry hair, dry skin, dry eyes, poor growth, night blindness, abscesses, insomnia, fatigue, reproductive system problems, sinusitis, pneumonia, frequent respiratory problems, skin disorders, weight loss, rickets, osteomalacia, nervousness, muscle spasms, leg cramps, extremity numbness, bone malformations, decayed teeth, difficulty in walking, irritability, restlessness, profuse sweating, increased uric acid (gout), joint damage, damaged red blood cells, destruction of nerves, infertility, miscarriage, and many types of cancer.

Did you know?

Carbamazepine can interfere with the results of home pregnancy tests. If you are taking carbamazepine, do not try to test for pregnancy at home.

Did you know?

Certain rare plants containing cyanide include apricot pits and a type of potato called cassava. Fortunately, only chronic or massive ingestion of any of these plants can lead to serious poisoning.

Did you know?

Once thought to have neurofibromatosis, Joseph Merrick (also known as "the elephant man") is now, in retrospect, thought by clinical experts to have had Proteus syndrome. This endocrine disease causes continued and abnormal growth of the bones, muscles, skin, and so on and can become completely debilitating with severe deformities occurring anywhere on the body.

For a complete list of videos, visit our video library