1
$\begingroup$

Apologies if this is the wrong group for this question, I am not sure whether it has to be posted here or in Aviation.

As far as I know most of composite fiber metal laminates are used in aviation. A lot of sources explaining the preparation of these materials tell that the most effective way to bond the fiber with the metal is to put the panels in a controlled atmosphere (often near vacuum) and let the binding resin (most of the times epoxy) to cure.

But then when this kind of panels are used to build something big as the fuselage of a passenger plane how are the panels joined to the structure? The most curious example are GLARE panels which is a composite of fiberglass and aluminium and were used to build the fuselage of the Aibus A380. I assume that you cannot put an entire fuselage in controlled atmosphere, are they glued to the structure anyway?

$\endgroup$
3
  • $\begingroup$ Airbus would know, but they may not want to tell you. And I have a friend who works there... Interesting stories I hear as we are both engineers. $\endgroup$
    – Solar Mike
    Aug 15 at 13:05
  • $\begingroup$ Probably epoxy. EDIT: I just realized your asking about inter-bonding of panels, not intra-bonding of panels. Screws and rivets can still be specified for use on composites too. $\endgroup$
    – DKNguyen
    Aug 15 at 20:19
  • $\begingroup$ The OP is asking how the panels are put together and connected to the main skeletons. I think it is a combination of rivets and welding. $\endgroup$
    – r13
    Aug 15 at 22:04
1
$\begingroup$

According to this article, composites on the F-35 are used almost exclusively in skin applications. (Below are excerpts from the article. Please read the original for more details)

During the F-35’s SDD phase, production of skin sections has differed, depending on the supplier, the part’s complexity and cost effectiveness. ATK, for instance, uses automated fiber placement (AFP) technology to produce many of the wing composite parts. Lockheed internally chose to produce the forward fuselage skins using hand layup.

At Lockheed Martin in Fort Worth, forward fuselage skins are hand-layed on Invar 35 tooling and cured in one of three large autoclaves built by Taricco Corp. (Long Beach, Calif.). Sacrificial plies cured into the laminates are subsequently machined to control thickness of the skins. At ATK, fiber-placed skins for the wing are cured and, following cure, skin thickness is precisely measured using a process developed by Lockheed Martin’s Manufacturing Technology & Production Engineering personnel. If needed, additional plies are layed up and the entire structure is cured a second time in a process called cured laminate compensation (CLC).

Once the composite skins are molded, trimmed and inspected, they are ready for attachment to constituent airframe structures. This is accomplished with fasteners drilled through the skin and into the frame at predetermined locations. Management and optimization of drilling on the weight-sensitive F-35 has become a significant effort, and part of the SDD process involves evaluation of drills, drilling tool geometry, tool efficiency, tool life, hole-drilling time, cost per hole drilled and other variables.

Born says the substructure provides backing for the skin and, therefore, helps prevent delamination.

$\endgroup$
2
  • $\begingroup$ One answer pointing to epoxy and the other pointing to fasteners. Rivets also mentioned in the comments. For the moment this seems the most likely. $\endgroup$
    – FluidCode
    Aug 16 at 12:34
  • $\begingroup$ @FluidCode All are involved depending on the task - skins are laminated on a tooling frame to form the shape, cured in the autoclave, grained smooth, finally drilled, and fastened to the backing frame. $\endgroup$
    – r13
    Aug 16 at 17:36
0
$\begingroup$

ANYTHING involving composites involves adhesives or epoxies.

https://www.masterbond.com/applications/composite-metal-adhesives-bonding

$\endgroup$
1
  • $\begingroup$ Polyester and phenolic resins. Checkmate! On the epoxy front at least. $\endgroup$
    – DKNguyen
    Aug 15 at 22:12

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.