Disclaimer: I work at the leading composite research group in the world, center of excellence for all branches of the military, along with having Boeing, and other aircraft manufatures come to US for help.
1: Carbon fiber and Graphite fiber are almost the same thing. One is 99% carbon, the other is 99.99% carbon. @davetileguy, give up, you are an idiot. Don't discount the composite professionals here that have 20x better grammar than you.
Где нађоше ова два дебила? Не умеју ни да држе чекић у руци...:)
Испод места удара, треба поставити подупирач, да би се енергија удара апсорбовала у тачки. Овако, на ивице ослоњена плоча, само еластично амортизује...
One of the biggest problems with composites in the aerospace industry is the huge loss in compressive strength after a low velocity energy impact. Although in this demonstration the composite looks as though it is tough, a lot of damage will have occured within the laminate struture. This is a serious problem since a workman's hammer falling on the wing, birdstrike and hail can cause significant undetected damage to the structure. Methods to check damage: Ultrasound. are time consuming.
@reloadedbarrel their exist a paint with microglass beeds containing paint of a different color forever wet that could be used as a strike indicator. i have seen it tested, but i domt know if they plan to use it.
@datzfast - Thanks for putting it forward, It sounds like a good idea on paper. I'm a bit skeptical on its scalability though, more to do with whether or not these beads cause a negative effect on the mateiral's overal properties.
This technology sounds similar to 'self healing CFRP' where micro tubes of glass resin are combined with the carbon fibres and are designed to break on impact, repairing the damaged region.
Good points tjp333. NDT of graphite based composites are expensive and time consuming mostly because none of them work in all cases. Some work better to find delamination, some work better to find micro-cracks, etc. Ultrasound, Thermography, Mechanical Impedence, Microwave, etc. Then when you DO find the problem, reparing it can be problematic. Patches and other repairs have very little error of margin for failure compared to patches / repairs made to more traditional materials like aluminum.
I agree. It's obvious to me that they do believe they can fool many people and if you look at a good portion of the comments relating to this topic, it's also obvious that they are succeeding in that regard. Unfortunately it seems the truth is being replaced the world over by "perception". Not just on technical topics, but pretty much everything. People are choosing to believe whatever fits their point of view, instead of the truth. I call that "willful ignorance". It's beyond frustrating.
Just as frustrating is the glaring inability of so many people to actually listen to what is being said. Nowhere does Mr. Weldon say C/G composites shouldn't be used on aircraft. What he said is that he believes that a C/G composite fuselage for a commercial airliner requires more testing and development, especially in regard to it's lack of toughness (ability to absorb impact) and how that will affect crashworthiness. As an engineer myself I view that as very sound engineering judgement.
It IS sound engineering judgement. He seems to be suggesting that Boeing's jumping too far ahead, too soon - even the FAA can't keep up. That's bad news - how can the agency responsible for issuing it's US Certificate of Airworthiness be confident in the 787's design if, according to Weldon, they don't fully understand it's design limitations.
Aerospace technology has always advanced rapidly but, in the interests of public safety, let's hope Boeing hasn't bitten off more than it can chew.
@tjp353 composite panels have been used on aircraft flight surfaces for a very long time, at least thirty years. in addition helicopter entire structures have been in use a very long time. i think the time has come for commercial airlines to take advantage of composite strengths but its all going to boil down to the life span weather its successful or not. i would have like to have seen it used on cargo for the last 20 years as proof of concept. passengers will become the guinea pig instead.
@datzfast. True, the A300 & MiG29 vertical tails & AV8B/Harrier2 front fuse & wing are some earlier major applications. It's a fantastic material for wings/tails, but is it good for fuselages?
Boeing still use a frame/stringer construction in the 787 fuselage. The aluminium skins I've seen on other airliners are around 1mm (0.040") thick. How thick is the 787's CFRP skin that replaces this? Acres of thin CFRP skin will be easily damaged and be an NDT testers nightmare. Only time will tell.
@tjp353 composite panels have been used on aircraft flight surfaces for a very long time, at least thirty years. in addition helicopter entire structures have been in use a very long time. i think the time has come for commercial airlines to take advantage of composite strengths but its all going to boil down to the life span weather its successful or not. i would have like to have seen it used on cargo for the last 20 years as proof of concept. passengers will become the guinea pig instead.
The simple fact that you CAN'T see a dent makes it all the more dangerous - it's not easy to detect where the damage is, but it IS there. Since CFC is prone to delamination upon impact, if you don't know exactly where the damage is you must ultrasonically scan potentially huge areas before you find it. Sounds expensive and time consuming to me.
This is very deceiving. GFRP does not "dent". I'm sure they know this but are counting on non-engineers to not know. GFRP is very strong and stiff for it's weight, but also very brittle. What they aren't showing you is the micro-cracks that surely developed internally from the impacts. And they're almost always impossible to see with the naked eye. GFRP and other composites have some great qualities and work fantastically well for certain applications. But when they fail they crack / shatter.
@GoogleEqualsEvil ah you must have seen the leading edge of the space shuttle, the one that a piece of foam blasted a hole into it and then because no one cared to take a peak at burned like a sparkler on independance day.
@davetileguy It does not. I based my assumption on 1) The 787's extensive (majority) use of Graphite Fiber Reinforced Plastic throughout, including primary structure 2) The large amount of criticism from knowledgeable engineers (including myself) about using GFRP so extensively, especially on fuselage structure, without significantly more testing 3) Boeing reactively trying to dispel such criticism with absurd "demonstrations" such as this.
@GoogleEqualsEvil 1. It's Carbon Fiber not "Graphite" 2. Your not more qualified than Boeing's combined qualified engineers. 3. That's what NDT is for.
@davetileguy Graphite IS "Carbon Fiber". I'm more than qualified to speak on the subject. NDT is very expensive to use on an overall, continuous basis. But I would highly recommend that Boeing institute a standard NDT policy that is enforced by the FAA for inspection of every 787. But that will never happen because of the economics involved.
@GoogleEqualsEvil Carbon fiber is a form of graphite in which these sheets are long and thin. You might think of them as ribbons of graphite. Bunches of these ribbons like to pack together to form fibers, hence the name carbon fiber. If you know so much than call it by it's correct name . Birch and Cedar are "wood" they are not the same. There are no NDT standard because their all used differently for different reasons ,Delam,water,cracks,voids,side,access,top bottom.
@davetileguy You truly are an ignorant moron. You have absolutely no idea what you're talking about. Stick to laying tile and leave the aerospace and mechanical engineering to qualified professionals like myself. I have over 30 years of design and engineering experience (along with a BSAE and MSME) in both the aerospace and commercial industries. That includes a large amount of experience with composites, including graphite / carbon fiber reinforced composites.
@GoogleEqualsEvil suure you do ,you just think graphite and CF are the same ?, black stringy stuff,Tile is what I used to do I went school and now repair the materials made in the Seattle area your so arrogantly familiar with, I stated the truth which is why your upset.
@davetileguy Epic fail. I'm not upset at all. I'm just tired of people like you speaking on a subject as if you're an authority, when the truth is that you clearly have no idea what you're talking about.
It's a scary thought to think an arrogant tool like you is actually fabricating / repairing the composite components that I design, engineer, and develop. As scary as watching the clowns in this video bang on a composite panel thinking that they are proving it's "tough".
@davetileguy Even if this is Kevlar based composite instead of Graphite (Kevlar composite is significantly tougher than Graphite based composite), it still can be (and likely was), damaged internally from the impacts shown. That kind of internal damage may take years to show up, and since it is so hard to detect visually, likely would go unnoticed unless inspected by appropriate NDT. Ask Boeing to show an Ultrasound, X-Ray and Thermographic inspection of this panel.
This "stuff" is very flammable. The epoxies Boeing uses as the matrix in this GFRP (Graphite Fiber Reinforced Plastic) are very flammable and when the graphite itself starts burning it releases toxic fumes. It's so flammable that it is banned from being used in the interior of any aircraft by the FAA. It's definitely not the kind of material I would want to be surrounded by if it was shattered and burning (like after a crash / hard landing).
@knonist - It depends on the material's thickness. A standard 4-5mm thick panel will easily be damaged by 25J of energy. I've done work with 1mm panels where only 0.6J was enough to cause internal damage.
I wonder if those guys ever heard about delamination and its consequences...
karpiu121 2 days ago
Disclaimer: I work at the leading composite research group in the world, center of excellence for all branches of the military, along with having Boeing, and other aircraft manufatures come to US for help.
1: Carbon fiber and Graphite fiber are almost the same thing. One is 99% carbon, the other is 99.99% carbon. @davetileguy, give up, you are an idiot. Don't discount the composite professionals here that have 20x better grammar than you.
2: boat panels are nothing like aircraft stresses
riff42 5 months ago 3
What will happen when micro cracks inside the laminate occur?
biped19 1 year ago
Где нађоше ова два дебила? Не умеју ни да држе чекић у руци...:)
Испод места удара, треба поставити подупирач, да би се енергија удара апсорбовала у тачки. Овако, на ивице ослоњена плоча, само еластично амортизује...
ZoranM001 1 year ago
Yep. They might not see it, but the damage is there. A metal fix: pretty easy. Drilling and scarfing in a composite repair, plus cure...not as much.
MOLRobocop 1 year ago
I think the worry isn't the strength and rigidity of the composite but the fact that once it's broken it's broken.
It might be able to take a harder impact without immediate failure but that during a crash it will shatter.
flanksteak1 2 years ago 4
One of the biggest problems with composites in the aerospace industry is the huge loss in compressive strength after a low velocity energy impact. Although in this demonstration the composite looks as though it is tough, a lot of damage will have occured within the laminate struture. This is a serious problem since a workman's hammer falling on the wing, birdstrike and hail can cause significant undetected damage to the structure. Methods to check damage: Ultrasound. are time consuming.
reloadedbarrel 2 years ago
@reloadedbarrel their exist a paint with microglass beeds containing paint of a different color forever wet that could be used as a strike indicator. i have seen it tested, but i domt know if they plan to use it.
datzfast 1 year ago
@datzfast - Thanks for putting it forward, It sounds like a good idea on paper. I'm a bit skeptical on its scalability though, more to do with whether or not these beads cause a negative effect on the mateiral's overal properties.
This technology sounds similar to 'self healing CFRP' where micro tubes of glass resin are combined with the carbon fibres and are designed to break on impact, repairing the damaged region.
reloadedbarrel 1 year ago
HAHA, I'm guessing they didn't discuss BVID on this demonstration? Barely visible impact damage.
You can impact a panel, and have little or no visible damage and have delaminations the size of a grapefruit.
zachks 2 years ago
Good points tjp333. NDT of graphite based composites are expensive and time consuming mostly because none of them work in all cases. Some work better to find delamination, some work better to find micro-cracks, etc. Ultrasound, Thermography, Mechanical Impedence, Microwave, etc. Then when you DO find the problem, reparing it can be problematic. Patches and other repairs have very little error of margin for failure compared to patches / repairs made to more traditional materials like aluminum.
GoogleEqualsEvil 3 years ago 4
The worrying thing is, some people will be very impressed at how 'tough' the 787 'is'.
If this is a genuine Boeing video I'm surprised that they think they can fool so many people.
I wonder if Mr Weldon would laugh or cry?!
tjp353 3 years ago 5
I agree. It's obvious to me that they do believe they can fool many people and if you look at a good portion of the comments relating to this topic, it's also obvious that they are succeeding in that regard. Unfortunately it seems the truth is being replaced the world over by "perception". Not just on technical topics, but pretty much everything. People are choosing to believe whatever fits their point of view, instead of the truth. I call that "willful ignorance". It's beyond frustrating.
guitarsandampsguy 3 years ago 2
Just as frustrating is the glaring inability of so many people to actually listen to what is being said. Nowhere does Mr. Weldon say C/G composites shouldn't be used on aircraft. What he said is that he believes that a C/G composite fuselage for a commercial airliner requires more testing and development, especially in regard to it's lack of toughness (ability to absorb impact) and how that will affect crashworthiness. As an engineer myself I view that as very sound engineering judgement.
guitarsandampsguy 3 years ago 9
It IS sound engineering judgement. He seems to be suggesting that Boeing's jumping too far ahead, too soon - even the FAA can't keep up. That's bad news - how can the agency responsible for issuing it's US Certificate of Airworthiness be confident in the 787's design if, according to Weldon, they don't fully understand it's design limitations.
Aerospace technology has always advanced rapidly but, in the interests of public safety, let's hope Boeing hasn't bitten off more than it can chew.
tjp353 3 years ago 4
@tjp353 composite panels have been used on aircraft flight surfaces for a very long time, at least thirty years. in addition helicopter entire structures have been in use a very long time. i think the time has come for commercial airlines to take advantage of composite strengths but its all going to boil down to the life span weather its successful or not. i would have like to have seen it used on cargo for the last 20 years as proof of concept. passengers will become the guinea pig instead.
datzfast 1 year ago
@datzfast. True, the A300 & MiG29 vertical tails & AV8B/Harrier2 front fuse & wing are some earlier major applications. It's a fantastic material for wings/tails, but is it good for fuselages?
Boeing still use a frame/stringer construction in the 787 fuselage. The aluminium skins I've seen on other airliners are around 1mm (0.040") thick. How thick is the 787's CFRP skin that replaces this? Acres of thin CFRP skin will be easily damaged and be an NDT testers nightmare. Only time will tell.
tjp353 1 year ago
This has been flagged as spam show
@tjp353 composite panels have been used on aircraft flight surfaces for a very long time, at least thirty years. in addition helicopter entire structures have been in use a very long time. i think the time has come for commercial airlines to take advantage of composite strengths but its all going to boil down to the life span weather its successful or not. i would have like to have seen it used on cargo for the last 20 years as proof of concept. passengers will become the guinea pig instead.
datzfast 1 year ago
The simple fact that you CAN'T see a dent makes it all the more dangerous - it's not easy to detect where the damage is, but it IS there. Since CFC is prone to delamination upon impact, if you don't know exactly where the damage is you must ultrasonically scan potentially huge areas before you find it. Sounds expensive and time consuming to me.
tjp353 3 years ago 4
This comment has received too many negative votes show
RETARD AMERICANS...
Composite´s defects are not visible, You´ll need ultrasound tests to evidence them.
What a bunch of Tards.
If this are the engineers that developed 787 Delay Liner`s Wings, wait for a catastrophic event to happen.
Boeing hasn´t learnt from McDonnell Douglas Big Errors in the past: namely the DC-10.
The 787 Delay Liner 20 Months behind schedule is just a bad Joke.
arsenium666 3 years ago
This is very deceiving. GFRP does not "dent". I'm sure they know this but are counting on non-engineers to not know. GFRP is very strong and stiff for it's weight, but also very brittle. What they aren't showing you is the micro-cracks that surely developed internally from the impacts. And they're almost always impossible to see with the naked eye. GFRP and other composites have some great qualities and work fantastically well for certain applications. But when they fail they crack / shatter.
GoogleEqualsEvil 3 years ago 12
@GoogleEqualsEvil ah you must have seen the leading edge of the space shuttle, the one that a piece of foam blasted a hole into it and then because no one cared to take a peak at burned like a sparkler on independance day.
datzfast 1 year ago
@GoogleEqualsEvil Where does it say this material is GFRP?
davetileguy 7 months ago
@davetileguy It does not. I based my assumption on 1) The 787's extensive (majority) use of Graphite Fiber Reinforced Plastic throughout, including primary structure 2) The large amount of criticism from knowledgeable engineers (including myself) about using GFRP so extensively, especially on fuselage structure, without significantly more testing 3) Boeing reactively trying to dispel such criticism with absurd "demonstrations" such as this.
GoogleEqualsEvil 6 months ago
@GoogleEqualsEvil 1. It's Carbon Fiber not "Graphite" 2. Your not more qualified than Boeing's combined qualified engineers. 3. That's what NDT is for.
davetileguy 6 months ago
@davetileguy Graphite IS "Carbon Fiber". I'm more than qualified to speak on the subject. NDT is very expensive to use on an overall, continuous basis. But I would highly recommend that Boeing institute a standard NDT policy that is enforced by the FAA for inspection of every 787. But that will never happen because of the economics involved.
GoogleEqualsEvil 6 months ago 2
@GoogleEqualsEvil Carbon fiber is a form of graphite in which these sheets are long and thin. You might think of them as ribbons of graphite. Bunches of these ribbons like to pack together to form fibers, hence the name carbon fiber. If you know so much than call it by it's correct name . Birch and Cedar are "wood" they are not the same. There are no NDT standard because their all used differently for different reasons ,Delam,water,cracks,voids,side,access,top bottom.
davetileguy 6 months ago
@davetileguy You truly are an ignorant moron. You have absolutely no idea what you're talking about. Stick to laying tile and leave the aerospace and mechanical engineering to qualified professionals like myself. I have over 30 years of design and engineering experience (along with a BSAE and MSME) in both the aerospace and commercial industries. That includes a large amount of experience with composites, including graphite / carbon fiber reinforced composites.
GoogleEqualsEvil 6 months ago
@GoogleEqualsEvil suure you do ,you just think graphite and CF are the same ?, black stringy stuff,Tile is what I used to do I went school and now repair the materials made in the Seattle area your so arrogantly familiar with, I stated the truth which is why your upset.
davetileguy 6 months ago
@davetileguy Epic fail. I'm not upset at all. I'm just tired of people like you speaking on a subject as if you're an authority, when the truth is that you clearly have no idea what you're talking about.
It's a scary thought to think an arrogant tool like you is actually fabricating / repairing the composite components that I design, engineer, and develop. As scary as watching the clowns in this video bang on a composite panel thinking that they are proving it's "tough".
GoogleEqualsEvil 6 months ago
@GoogleEqualsEvil How well did NDT work on the Aloha flight ?
davetileguy 6 months ago
@davetileguy Even if this is Kevlar based composite instead of Graphite (Kevlar composite is significantly tougher than Graphite based composite), it still can be (and likely was), damaged internally from the impacts shown. That kind of internal damage may take years to show up, and since it is so hard to detect visually, likely would go unnoticed unless inspected by appropriate NDT. Ask Boeing to show an Ultrasound, X-Ray and Thermographic inspection of this panel.
GoogleEqualsEvil 6 months ago 2
@GoogleEqualsEvil Why don't inferior polyester boat panels delam after spending a life time being pounded and run up on the beach? (just asking)
davetileguy 6 months ago
You don't want this stuff to be flammable, otherwise it'll be another Hindenburg.
JustMakingComments 3 years ago
This "stuff" is very flammable. The epoxies Boeing uses as the matrix in this GFRP (Graphite Fiber Reinforced Plastic) are very flammable and when the graphite itself starts burning it releases toxic fumes. It's so flammable that it is banned from being used in the interior of any aircraft by the FAA. It's definitely not the kind of material I would want to be surrounded by if it was shattered and burning (like after a crash / hard landing).
GoogleEqualsEvil 3 years ago 6
I am by far an expert but I think it's because epoxies used in CFs have a very Good memory so load is takes as flew.
i have acarbon fiber fishing rod that cracked very quickly :(
mjok2004 3 years ago
things are more complicared than that.:aluminium corrodes,and cracks propagate in aluminium.
CF can be moulded ,not rivet crack initaiation,and higher tensile strength.
but CF is questionned by experts in civilian applications.
jeetendrag10 3 years ago
so what, you only need 25J to damage a carbon comsite panel.....
knonist 3 years ago
@knonist - It depends on the material's thickness. A standard 4-5mm thick panel will easily be damaged by 25J of energy. I've done work with 1mm panels where only 0.6J was enough to cause internal damage.
reloadedbarrel 1 year ago
The point is aluminum would be f*ckd!
LILBRAZ 3 years ago
There may not be visual damage on the panel but im sure if you NDT it with ultrasonic inspection methods you will find damage.
8200rpm 4 years ago 3
obviously its a matter of how hard you look.. i think the point their making is thats its pretty strong stuff
grandmastarflash 3 years ago