Carbon Composite Material. We might be waiting for a bigger air accident

[RajaRawal111]

I was watching a video one of my friends sent me about the Titan accident. The surprising information in it was that the carbon composite material (with which this submarine was made) is not suitable for compressional stresses. This material is proven good for tensile stresses (the pulling stresses). The composite materials are very successful in high-pressure cylinders. The compressed gas in these cylinders exerts internal pressure which tends to pull the material, exerting tensile stress on it. Material scientists have done countless experiments and proven it to be much better than steel and titanium-like metals. This led the industry to start building commercial Airplanes with this material. Boing was the leader and now Airbus is also following them. Every 2nd airplane being made is fabricated with carbon composite material.

The inherent danger in this material is that once it is made the only test is by pressurizing it internally and listening to the Acoustics waves it generates. (This is a non-destructive technique called as "Acoustic Emission"). Unfortunately, there is no other non-destructive technique that works on carbon composite materials. Once an airplane fuselage is made with carbon composite material, there is no way to pressurize it enough so that it generates the Acoustic signatures of the flaws hidden inside the material.

So we might be waiting for an even bigger disaster in the air, because of the lack of proper testing after an aircraft is built. Any inherent unknown crack in the material can catastrophically progress and split an aircraft into two pieces in mid-air.

I hope, after this accident of Titan, the Govts of these developed nations will now start paying some attention and put their foot on the brakes with this material. Until some means of non-conventional testing of this material are developed.

arifkarim Shahid Abassi Sohail Shuja surfer

 

[siasat.us]

Create a change.org petition.

 

[Kam]

Sorry my friend, I did not understand at all.
At depths, submarines have to face extreme pressure as compared to surface or near surface depth.
But plane once in air, cabin pressure is maintained at almost atmospheric pressure and external pressure reduces due to thin air.

So what you want to say? I think carbon material testing is not any issue today. I think as of date, airlines are using state of the art technology to find any defects in the material.

Yes we cannot fight nature.

 

[saleema]

Yeh to carbon fibers Nahi Bao g or TT shareef howay...with pressure they rupture, implodes and explodes...if you don't believe ask Zardari he is doing their non destructive testing with beghayrate model in Punjab.

 

[saleema]

I was watching a video one of my friends sent me about the Titan accident. The surprising information in it was that the carbon composite material (with which this submarine was made) is not suitable for compressional stresses. This material is proven good for tensile stresses (the pulling stresses). The composite materials are very successful in high-pressure cylinders. The compressed gas in these cylinders exerts internal pressure which tends to pull the material, exerting tensile stress on it. Material scientists have done countless experiments and proven it to be much better than steel and titanium-like metals. This led the industry to start building commercial Airplanes with this material. Boing was the leader and now Airbus is also following them. Every 2nd airplane being made is fabricated with carbon composite material.

The inherent danger in this material is that once it is made the only test is by pressurizing it internally and listening to the Acoustics waves it generates. (This is a non-destructive technique called as "Acoustic Emission"). Unfortunately, there is no other non-destructive technique that works on carbon composite materials. Once an airplane fuselage is made with carbon composite material, there is no way to pressurize it enough so that it generates the Acoustic signatures of the flaws hidden inside the material.

So we might be waiting for an even bigger disaster in the air, because of the lack of proper testing after an aircraft is built. Any inherent unknown crack in the material can catastrophically progress and split an aircraft into two pieces in mid-air.

I hope, after this accident of Titan, the Govts of these developed nations will now start paying some attention and put their foot on the brakes with this material. Until some means of non-conventional testing of this material are developed.

arifkarim Shahid Abassi Sohail Shuja surfer

Ek Qatri test BHI hai lekin Woh destructive test hai...Maryam has undergone that test and she has passed it with her fibers totally destroyed from inside..vekh lo rajwaray

 

[Citizen X]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm which

Its like comparing apples to samosas.
Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also carbon fiber can be testing using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.

 

[RajaRawal111]

Sorry my friend, I did not understand at all.
At depths, submarines have to face extreme pressure as compared to surface or near surface depth.
But plane once in air, cabin pressure is maintained at almost atmospheric pressure and external pressure reduces due to thin air.

So what you want to say? I think carbon material testing is not any issue today. I think as of date, airlines are using state of the art technology to find any defects in the material.

Yes we cannot fight nature.

Agree with you about the lesser pressure differential in the air compared to the deep sea pressure.
My point is that being not able to test this material in the fuselage Structure. The cyclic stresses in countless takeoffs and landings may generate micro-cracks in the fuselage. The industry has no conventional technique to detect these cracks. Ultrasonic cannot go through this material and X-ray is not able to see micro cracks. So in other words, once an airplane is made there is no testing of this material. .

 

[RajaRawal111]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm which

Its like comparing apples to samosas.
Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also carbon fiber can be testing using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.

Come on Man I was just talking about the ultrasonic testing in my post No 6.
You need a longer wavelength to make the sound go through the composite material and Ultrasonic is more sensitive in shorter wavelengths.
Eddy current is inductive technique. Which is absolutely not possible on composite materials.

Even though I enjoy working with your a22 on political matters but for this subject we can put it off and discuss it humanely.
Tell me if I should take you deeper into the ultrasonic and other non-destructive techniques, and explain how it does not work on Carbon composites.

 

[Citizen X]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm while the deep sea challenger submersible has a skin thickness of 64mm.

Its like comparing apples to samosa's!


Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, Rush never got it certified because he knew it would never pass, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also unknown to patwari brains ( not a surpise ) carbon fiber can be tested using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

Also carbon fiber is much stronger and lighter in everyway and is more resistant to damage and tearing up.

Here is something new generation GE airplane engines which previously had titanium blades are now made of carbon fiber i.e carbon fiber replacing one of the strongest know metal to man. Only the leading edge is coated in titanium.

And I know a thing or two about the safety checks airplanes and their engines go through and their frequency. If there was no way to check hull or blade integrity the planes and engine would never pass certification and never be allowed to fly commercial passengers.

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.



EDIT : ADDED SOME EXTRA POINTS BUT HAD TO REPOST AS THE 8 MIN TIME LIMIT TO EDIT THE POST HAD RUN OUT.

 

[Kam]

Agree with you about the lesser pressure differential in the air compared to the deep sea pressure.
My point is that being not able to test this material in the fuselage Structure. The cyclic stresses in countless takeoffs and landings may generate micro-cracks in the fuselage. The industry has no conventional technique to detect these cracks. Ultrasonic cannot go through this material and X-ray is not able to see micro cracks. So in other words, once an airplane is made there is no testing of this material. .

Never worked in an airliner. But 100% that structural integrity test are mandatory after a certain period of time.
For specific answer, have to study.

 

[RajaRawal111]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm which

Its like comparing apples to samosas.
Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also carbon fiber can be testing using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.

Your link is from an NDT service provider or manufacturer and in the same link following is written about Eddy current technique.

Eddy Current Testing of Carbon Fiber​

Despite the low conductivity of carbon fiber, some have claimed that eddy current testing can effectively inspect this material. However, the wide variability of results argues against the use of eddy current inspection techniques. Rarely, if ever, will eddy current testing be preferred over ultrasound for inspecting carbon fiber.

 

[RajaRawal111]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm while the deep sea challenger submersible has a skin thickness of 64mm.

Its like comparing apples to samosa's!


Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, Rush never got it certified because he knew it would never pass, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also unknown to patwari brains ( not a surpise ) carbon fiber can be tested using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

Also carbon fiber is much stronger and lighter in everyway and is more resistant to damage and tearing up.

Here is something new generation GE airplane engines which previously had titanium blades are now made of carbon fiber i.e carbon fiber replacing one of the strongest know metal to man. Only the leading edge is coated in titanium.

And I know a thing or two about the safety checks airplanes and their engines go through and their frequency. If there was no way to check hull or blade integrity the planes and engine would never pass certification and never be allowed to fly commercial passengers.

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.



EDIT : ADDED SOME EXTRA POINTS BUT HAD TO REPOST AS THE 8 MIN TIME LIMIT TO EDIT THE POST HAD RUN OUT.

Never worked in an airliner. But 100% that structural integrity test are mandatory after a certain period of time.
For specific answer, have to study.

Citizen X, I told you about inability of Eddy Current testing in post No 10. Here is one publication on the study of Ultrasonic testing on composite material. It is at Science Direct website.

https://www.sciencedirect.com/science/article/pii/S2588840420300342

If you don't want to read the whole article, at least read this in the conclusion section.

"In particular, the A-scan acquisition (Amplitude versus thickness) shows a higher signal absorption in the vinylester composites and the consequent higher difficulty to detect the top and the bottom signal"

 

[Citizen X]

Never worked in an airliner. But 100% that structural integrity test are mandatory after a certain period of time.
For specific answer, have to study.

Its called a D test where the plane is literally stripped down to its nuts and bolts and everything is gone over with a fine tooth comb. It is mandatory after 6 years.

Then their are obviously the A, B, C checks, starting with every 10 weeks, then 18 months, two years and so on.

And airplane usage is counted in cycles rather than hours it flies, because every time the hull is pressurized and then depressurized is when its most stressed. An 18hr flight is less stressful to a plane than 5, one hour flights in a day. Which totally happens with budget airlines with one plane shuttling between two airports like a bus. Hence I always advice people to avoid budget airlines. Because they have to keep to their schedule.

So a 5 minute delay on 1st flight of the day adds a 5 minute delay to every flight that day and as they pick up delays on flights that just adds to the total delay of subsequent flights of the day which gives them less time to inspect and turn around the next flight, thats when mistakes tend to happen, to be in a rush and be on time. Even the pilots are stressed and start to suffer from get there-itis, A condition in which pilots start to make mistakes in order to land i.e get there sometimes with fatal consequences.

 

[Digital_Pakistani]

Patwari seems to be on some sort of attention diversion.

 

[RajaRawal111]

Patwari seems to be on some sort of attention diversion.

Keep this thread non-political, please.

 

[Citizen X]

Come on Man I was just talking about the ultrasonic testing in my post No 6.
You need a longer wavelength to make the sound go through the composite material and Ultrasonic is more sensitive in shorter wavelengths.
Eddy current is inductive technique. Which is absolutely not possible on composite materials.

Even though I enjoy working with your a22 on political matters but for this subject we can put it off and discuss it humanely.
Tell me if I should take you deeper into the ultrasonic and other non-destructive techniques, and explain how it does not work on Carbon composites.

The cyclic stresses in countless takeoffs and landings may generate micro-cracks in the fuselage.

First learn the properties of the material you are talking about. Carbon fiber is not ductile like metal so it does not go through expansion and contraction like regular hulls and hence not susceptible to fatigue which is turn cause stress fractures on metal, so there is no real need to test them ultrasonically.

It is exactly because of this that the Boeing 787 which has a hull made entirely of composite material can keep a higher pressure in the cabin making it more comfortable for the passengers, less ear popping etc etc.

And much much much greater minds than you work for like agencies FAA and EASA that have certified these aircraft commercial passenger usage. And unlike the current Republic Of Patwaristan, they are liable for their work, if some disaster happens and it is found that they certified something knowing that it could not be tested and repaired and put lives of 1000s of people at stake, they will have to pay for it dearly. So I don't think anyone would take that risk.

 

[Citizen X]

Patwari seems to be on some sort of attention diversion.

Patwari is trying show his academic prowess trying to compare wood with cow dung. But as always every time patwaris try to act smart it back fires in their faces.

 

[RajaRawal111]

Patwari is trying show his academic prowess trying to compare wood with cow dung. But as always every time patwaris try to act smart it back fires in their faces.

Even though you have blocked me and I still keep tagging you on political matters. But on this one, I did not. I tagged the only educated people I know on the forum.

You used to be some sort of Accountant/Munshi and now trying to become a material scientist. I have given you the scientific publications which prove my point, but they are beyond your understanding.

You must first learn about the properties of FRPs and materials. Idiot, the "modulus of elasticity" is the basic required property of a material to be used in mechanical services. Otherwise, materials undergoe brittle cracking under stress.

Quote from the below link:
Both carbon fiber and steel have moduli of elasticity upwards of 200 gigapascals (GPa) so either material is remarkably stiff and ideal for a number of high-stress applications.

Carbon Fiber vs Steel: Who Does It Better? | Zoltek

Both carbon fiber and steel offer superior strength and versatility. But which is better between carbon fiber vs steel? Let’s find out!

zoltek.com

 

[RajaRawal111]

First learn the properties of the material you are talking about. Carbon fiber is not ductile like metal so it does not go through expansion and contraction like regular hulls and hence not susceptible to fatigue which is turn cause stress fractures on metal, so there is no real need to test them ultrasonically.

It is exactly because of this that the Boeing 787 which has a hull made entirely of composite material can keep a higher pressure in the cabin making it more comfortable for the passengers, less ear popping etc etc.

And much much much greater minds than you work for like agencies FAA and EASA that have certified these aircraft commercial passenger usage. And unlike the current Republic Of Patwaristan, they are liable for their work, if some disaster happens and it is found that they certified something knowing that it could not be tested and repaired and put lives of 1000s of people at stake, they will have to pay for it dearly. So I don't think anyone would take that risk.

Replied to this above in post 17.

 

[Storm]

I just had to unblock this thread to check the stupidity of our resident patwari engineer/scientist and I was not disappointed at all, where is comparing the 4000psi of compressive pressure under water with a hull of an aircraft which is pressurized to 10 to 12 psi. One is trying to keep 4000 psi of pressure out while the is trying to keep 12 psi of pressure in. F.Y.I a cars tyre made of rubber has an average pressure of 30psi.

Also planes made of regular aluminum and alloys have a skin thickness of around 2.5 mm which

Its like comparing apples to samosas.
Also Ocean gate was not inspected and verified by any agency, it was basically like a kit car someone built in his shed, while a commercial airliner has to go 1000s of hour of testing and certification from aviation bodies like the FAA.

Also carbon fiber can be testing using NDTs

Understanding NDT of Carbon Fiber | Zetec

Advanced NDT techniques for testing carbon fiber allow analysts to detect internal cracking and other flaws with impressive efficiency and precision.

www.zetec.com

No wonder Pakistan is fucked when you have such brain less dim witted, patwari danish school products, working as engineers and scientists in govt depts and institutes.

onhahahahaahahaha ghulam paryam qatri ki youth ka ganda keera never disappoints

jis ka leader bilawal or maryam qatri ho us sy or kia expect kr skty ho rofl

yea Italy ja kr bhe boltay hain nehari pae kahan milain gy