The first composite development barrel—a sample of the fuselage structure—for the Boeing 787 Dreamliner program sat in its tooling fixture for less than three days before Boeing and its partners began to cut it apart.
“This is not a museum piece,” said Walt Gillette, vice president of Engineering, Manufacturing and Partner Alignment for the 787 program. “We built it so we could prove our concepts and learn better ways of producing large monolithic composite structures.”
Interesting graphic they have there
By: Distiller - 12th March 2005 at 09:46
I haven’t really found how they did it back on the Starship, but I found a little article that is quite interesting and e.g. mentiones how they solved the lightning thing back then.
http://www.aviatorservices.com/starship_history_1.htm
Seems like today they do it with an aluminum mesh. And then there is the question of conductivity of carbon fibre vs say boron or aramid fibre composites.
PS: Do you know what happens when older composites are hit by lightning? They are blown to pits and pieces because they tend to accumulate moisture within the structure and that turns to steam and blows apart the material.
By: Distiller - 12th March 2005 at 09:46
I haven’t really found how they did it back on the Starship, but I found a little article that is quite interesting and e.g. mentiones how they solved the lightning thing back then.
http://www.aviatorservices.com/starship_history_1.htm
Seems like today they do it with an aluminum mesh. And then there is the question of conductivity of carbon fibre vs say boron or aramid fibre composites.
PS: Do you know what happens when older composites are hit by lightning? They are blown to pits and pieces because they tend to accumulate moisture within the structure and that turns to steam and blows apart the material.
By: coanda - 11th March 2005 at 21:11
it is my understanding (which might be wrong…..) that boeing plan to literlally ‘spin’ the fuselage sections on a huge loom, doing so means that boeing can simply incorporate windows doors/a.n.other holes at this stage which is by far the strongest way to make apertures in composite structures…..as castor points out you have to know how the structure is loaded or you’ll just endup 1. making it understrength or 2. piling the layers and thus the weight on, ‘just to make sure’…….this is why metallic wins over composites for things like wing ribs as you can make a metallic rib lighter for the same strength, because of course it can be considered to have no primary axis of strength as such, unlike uni-axial tapes, however 3 direction plus fibre weaves exist, and are useful at the expense of drapability.
By: coanda - 11th March 2005 at 21:11
it is my understanding (which might be wrong…..) that boeing plan to literlally ‘spin’ the fuselage sections on a huge loom, doing so means that boeing can simply incorporate windows doors/a.n.other holes at this stage which is by far the strongest way to make apertures in composite structures…..as castor points out you have to know how the structure is loaded or you’ll just endup 1. making it understrength or 2. piling the layers and thus the weight on, ‘just to make sure’…….this is why metallic wins over composites for things like wing ribs as you can make a metallic rib lighter for the same strength, because of course it can be considered to have no primary axis of strength as such, unlike uni-axial tapes, however 3 direction plus fibre weaves exist, and are useful at the expense of drapability.
By: Grey Area - 11th March 2005 at 20:13
Hmmmm – lighting has a habit of ignoring conductive plastics.
It can’t be too hard to include a conductive matrix in large composite structures, and I’m sure it isn’t beyond Boeing.
Interesting times, for sure.
By: Grey Area - 11th March 2005 at 20:13
Hmmmm – lighting has a habit of ignoring conductive plastics.
It can’t be too hard to include a conductive matrix in large composite structures, and I’m sure it isn’t beyond Boeing.
Interesting times, for sure.
By: Distiller - 11th March 2005 at 08:54
I presume that conductive paths will also be built into the structure so as to present a Faraday Cage to lightning strikes?
A copper matrix I guess. Maybe conductive plastics, but I doubt it.
By: Distiller - 11th March 2005 at 08:54
I presume that conductive paths will also be built into the structure so as to present a Faraday Cage to lightning strikes?
A copper matrix I guess. Maybe conductive plastics, but I doubt it.
By: Distiller - 11th March 2005 at 08:53
Distiller, normally you make some kind of reinforcement around these cut outs, and as previously stated, you construct your load paths in such a way that they don’t come near these weak areas.
And when it comes to fibre in general, you have to calculate load paths in advance so that you know how you should put the fibre direction. In that way, you adapt the material to have very good properties in the load directions and weak properties in all other directions. If you’re not sure of the load path, or if you have loads coming from all kinds of directions you just put a 45 / 45 layered composite.
regards,
Castor
I know all that. 😉
Have to look if I find something about the Beech Starship, how they did it back then.
By: Distiller - 11th March 2005 at 08:53
Distiller, normally you make some kind of reinforcement around these cut outs, and as previously stated, you construct your load paths in such a way that they don’t come near these weak areas.
And when it comes to fibre in general, you have to calculate load paths in advance so that you know how you should put the fibre direction. In that way, you adapt the material to have very good properties in the load directions and weak properties in all other directions. If you’re not sure of the load path, or if you have loads coming from all kinds of directions you just put a 45 / 45 layered composite.
regards,
Castor
I know all that. 😉
Have to look if I find something about the Beech Starship, how they did it back then.
By: Grey Area - 11th March 2005 at 07:35
I presume that conductive paths will also be built into the structure so as to present a Faraday Cage to lightning strikes?
By: Grey Area - 11th March 2005 at 07:35
I presume that conductive paths will also be built into the structure so as to present a Faraday Cage to lightning strikes?
By: Castor - 11th March 2005 at 07:29
Distiller, normally you make some kind of reinforcement around these cut outs, and as previously stated, you construct your load paths in such a way that they don’t come near these weak areas.
And when it comes to fibre in general, you have to calculate load paths in advance so that you know how you should put the fibre direction. In that way, you adapt the material to have very good properties in the load directions and weak properties in all other directions. If you’re not sure of the load path, or if you have loads coming from all kinds of directions you just put a 45 / 45 layered composite.
regards,
Castor
By: Castor - 11th March 2005 at 07:29
Distiller, normally you make some kind of reinforcement around these cut outs, and as previously stated, you construct your load paths in such a way that they don’t come near these weak areas.
And when it comes to fibre in general, you have to calculate load paths in advance so that you know how you should put the fibre direction. In that way, you adapt the material to have very good properties in the load directions and weak properties in all other directions. If you’re not sure of the load path, or if you have loads coming from all kinds of directions you just put a 45 / 45 layered composite.
regards,
Castor
By: MerlinXX - 11th March 2005 at 04:52
When is the first flight expected for this? I seem to remember seeing it is scheduled for 2007, although I personally doubt this if they are still experimenting with the technology they are going to use. Regarding the construction, my guess would be that the strands will be layered in multiple directions as I would imagine the forces exerted on the fuselage would change when it is pressurised and airborne to when it is on the ground.
By: MerlinXX - 11th March 2005 at 04:52
When is the first flight expected for this? I seem to remember seeing it is scheduled for 2007, although I personally doubt this if they are still experimenting with the technology they are going to use. Regarding the construction, my guess would be that the strands will be layered in multiple directions as I would imagine the forces exerted on the fuselage would change when it is pressurised and airborne to when it is on the ground.
By: Bmused55 - 10th March 2005 at 13:23
Ah Joker! Of course you need holes to enter/exit and look out. That wasn’t what I meant. The fact that they cut through the fibres looks strange to me, and I wondered if they layered the fibres in a way to support the structure around the holes or layed the fibres in a straight forward circular fashion. Intentionally hurting the fibres is simply not a good idea, you produce loose ends, and as we all know the fibres in reinforced plastics should follow the load path, and having loose ends will not help.
Your argument seems valid.
Though, lacking engineering degrees I couldn’t tell you if what Boeing are doing will indeed hurt the overall structure.
I do know however, that Boeing have experience with composits and I am certain they know what they are doing.
By: Bmused55 - 10th March 2005 at 13:23
Ah Joker! Of course you need holes to enter/exit and look out. That wasn’t what I meant. The fact that they cut through the fibres looks strange to me, and I wondered if they layered the fibres in a way to support the structure around the holes or layed the fibres in a straight forward circular fashion. Intentionally hurting the fibres is simply not a good idea, you produce loose ends, and as we all know the fibres in reinforced plastics should follow the load path, and having loose ends will not help.
Your argument seems valid.
Though, lacking engineering degrees I couldn’t tell you if what Boeing are doing will indeed hurt the overall structure.
I do know however, that Boeing have experience with composits and I am certain they know what they are doing.
By: Distiller - 10th March 2005 at 13:06
Then how do you expect passengers to enter and exit the 787? A star trek style transporter perhaps? :rolleyes:
Of course doors and windows are not good for structural integrity. Even on metal planes. But the Manufacturers get around them 😉
Ah Joker! Of course you need holes to enter/exit and look out. That wasn’t what I meant. The fact that they cut through the fibres looks strange to me, and I wondered if they layered the fibres in a way to support the structure around the holes or layed the fibres in a straight forward circular fashion. Intentionally hurting the fibres is simply not a good idea, you produce loose ends, and as we all know the fibres in reinforced plastics should follow the load path, and having loose ends will not help.
By: Distiller - 10th March 2005 at 13:06
Then how do you expect passengers to enter and exit the 787? A star trek style transporter perhaps? :rolleyes:
Of course doors and windows are not good for structural integrity. Even on metal planes. But the Manufacturers get around them 😉
Ah Joker! Of course you need holes to enter/exit and look out. That wasn’t what I meant. The fact that they cut through the fibres looks strange to me, and I wondered if they layered the fibres in a way to support the structure around the holes or layed the fibres in a straight forward circular fashion. Intentionally hurting the fibres is simply not a good idea, you produce loose ends, and as we all know the fibres in reinforced plastics should follow the load path, and having loose ends will not help.
Sign In
March 9, 2005 at 4:22 pm