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I am particularly interested in the Boeing 787 Fuselage because it is one of the first aircraft to carry such a high percentage of Carbon Fibre Reinforced Polymer (CFRP).

Can someone explain how the fuselage is made? I know the basics of making CFRP which include fibre being wrapped onto in mandrel in different orientations then heating in an autoclave to cure.

However, I also know that the whole fuselage is not produced in one piece. Pieces of the fuselage are produced then joined together.

  • I would like to know the joining process works.
  • Since it is not fabricated as a single piece there are bound to be stresses on the joints. Will it effect/endanger the passengers?
  • What loads can it take since the joints will cause a drop in overall pressure (what is the maximum pressure if possible). I don't think its being welded together but not sure the reason.
  • Are the same methods used to join the wings?
  • Last but not least, are there problems due to the joints before and if so, what has been done to rectify these problems?
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    $\begingroup$ Damn, after reading this question, now all I can think about is what an awesome sight an autoclave would be that would allow a 787 to be built as a single monocoque structure :-D $\endgroup$ – Jörg W Mittag Mar 27 '17 at 10:14
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    $\begingroup$ I doubt they're welded since welding consists of softening the material until the two pieces are liquid enough to flow together and become one solid piece. This works on both metal (heat is used to do the softening) and plastics (chemicals, called glue, are used to do the softening). $\endgroup$ – FreeMan Mar 27 '17 at 13:39
  • $\begingroup$ @JörgWMittag now that I think about it, I'm imagining the disaster of discovering a layup issue in one small section of that 1-piece monocoque, as opposed to a problem in a section. But, yeah, an autoclave that huge would be a sight to behold! $\endgroup$ – FreeMan Mar 28 '17 at 12:22
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There is a YouTube video showing the method for creating the structure:

YouTube: 787 Composite Construction

This video from British Airways shows the joining process:

Fuselage Section Joining Process which you can see is not welded, but riveted together. The sections are lined up and riveted together using joining plates.

Since it is not fabricated as a single piece there are bound to be stresses on the joints. Will it effect/endanger the passengers?

No, not more than any other conventionally constructed fuselage. The joining plates are metal and the structure around them is a metal bulkhead. The 787 fuselage is not a 100% composite construction.

Are the same methods used to join the wings?

Yes, if you watch the second linked video in full, you can see the composite wings being bolted to the fuselage structure. The entire wing support structure looks to be a conventional metal structure.

Last but not least, are there problems due to the joints before and if so, what has been done to rectify these problems?

There are new challenges with any type of new construction technique, here are a few articles that outline the challenges:

NY Times: New Challenges for the Fixers of Boeing’s 787
MIT Technology Review: Boeing's Composite Problem

Boeing has said that the 787 is as easy to repair as traditional aluminum skin aircraft. One case in point is the Ethiopian Airlines aircraft ET-AOP damaged by fire. The procedure to fix it is to cut out the carbon fiber material and put a "cure in place" patch over the hole. In this case other structure had to be replaced or repaired like stringers and bulkheads. This was the first major airframe repair that Boeing had to undertake. ET-AOP took 18 months to repair before being returned to service.

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    $\begingroup$ That would actually be rivets, not bolts. $\endgroup$ – TomMcW Mar 27 '17 at 23:58
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    $\begingroup$ @Ron Beyer you mention about the metal plates joining the 2 CFRP components together. Care to elaborate about "joining plates are metal and the structure around them is a metal bulkhead". Does this mean the order is CFRP component, metal plates, CFRP component? or is it CFRP component side by side and there is a joining metal plate in between. $\endgroup$ – user20738 Mar 28 '17 at 0:43
  • $\begingroup$ @TomMcW You are right, and I was half right :) The wings are bolted, the fuselage sections use rivets. $\endgroup$ – Ron Beyer Mar 28 '17 at 2:02
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    $\begingroup$ @user20738 I will add some detail tomorrow if nobody gets to it first. The hull sections are a carbon fiber skin laid over an aluminum substructure. In the entire fuselage, the 787 is 50% composite materials, not 100%. $\endgroup$ – Ron Beyer Mar 28 '17 at 2:04
  • $\begingroup$ Lol. I didn't watch past the first minute or so. Wanted to see if they really used bolts on the fuselage. That's a helluva riveting machine! +1 btw $\endgroup$ – TomMcW Mar 28 '17 at 13:47

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