NDT of large surface area thick laminates 2

[UKCambEngineer]

Hey

Hopefully I’m not treading on anyone’s toes with this thread?

Wondered if anyone could help? Got a bit of a challenge on my hands…… I’ve got to inspect a large glass fibre structure, roughly 80mm thk!

For thicker materials people generally run with thermography, ultrasonics or xray tomography! However the equipment needs to be reasonably mobile as I’m going to be hanging off a ladder! So I was thinking some kind of tapping equipment. However a standard tap hammer ‘woodpecker’ tool wont cut it, as its only really suited to detecting delams in thin material. Been in contact with Wichitch to see if they have a ‘heavy duty’ tap hammer, but no luck!

I was thinking some kind of civil engineering firm may produce something, but cant seem to find anything. But then how do they NDT the thicker parts of the new 787 or A350 wings? Surely that isn't done with a tap hammer?

Any of you guys know anything?

Cheers

 

[WKTaylor]

Thunderengineer...

some starting points...
----
SAE Documents.

ARP5089 Composite Repair NDT/NDI Handbook

ARP5606 Composite Honeycomb NDI Reference Standards

AIR4844 Composites and Metal Bonding Glossary
----
MIL-HDBK-731 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS - THERMOGRAPHY

MIL-HDBK-732 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS ACOUSTIC EMISSION

MIL-HDBK-733 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS - RADIOGRAPHY

MIL-HDBK-787 NONDESTRUCTIVE TESTING METHODS OF COMPOSITE MATERIALS-ULTRASONIC

MIL-HDBK-793 NONDESTRUCTIVE TESTING TECHNIQUES FOR STRUCTURAL COMPOSITES

MIL-HDBK-803 GLASS REINFORCED PLASTICS PREVENTIVE MAINTENANCE AND REPAIR

USAF T.O.s [if YOU can find copies]

1-1-690 GENERAL ADVANCED COMPOSITE REPAIR PROCESSES MANUAL

33B-1-1 NONDESTRUCTIVE INSPECTION METHODS, BASIC THEORY

33B-1-2 GENERAL PROCEDURES AND PROCESS CONTROLS

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

 

[SWComposites]

"how do they NDT the thicker parts of the new 787 or A350 wings? Surely that isn't done with a tap hammer?" Nope; it is down with ultrasonic inspection.

You might be able to do the inspection with hand held pulse echo ultrasonics, but it might take some development/validation work.

 

[UKCambEngineer]

Ok brilliant, gunna start by having a look at all those points.

Struggling to find a mthod that doesn't struggle with large thickness.

 

[Benbarca7]

Can you find in the SRM what control to apply to find delamination on the panel?

I was thinking that tap test was for disbond, not delamination.

For delamination of plies the first thing that comes to my mind is a Ultra sonic inspection, I think you can do it on large structure but it can take a lot of time (it is mobile). I would check again in the SRM if you can inspect a so thick part (I would think it is just a problem of calibration).

I am gonna check on some documents testing documents

Ben
Nacelle Stress Engineer (repair on Civil Aircraft)

 

[WKTaylor]

thunderengineer

OK fess-up.

I've suspected all along that this component is NOT aerospace, IE it's probably a: civil engineering structure [bridge, crane, etc]; or a large "tank" [fuel, oil. water, sewage, etc]; or a boat hull etc. OH yeas... and is probably matt-molded, pull-truded, wound-fiber etc NOT automated-tape-lay-up with autoclave press/temp for cure.

What is it really?

Hmmm... 80-MM thick glass fiber structures will likely be way too heavy for aero application, considering that carbon-fiber, or a carbon-boron, etc hybrids would have a much better strength/stiffness-to-weight ratio as a max-density composite structure.

Regards, Wil Taylor

Trust - But Verify!

We believe to be true what we prefer to be true.

For those who believe, no proof is required; for those who cannot believe, no proof is possible.

 

[moon161]

Big wind turbine blade, I bet.

I've seen boat hulls close to that thick.

 

[UKCambEngineer]

Hey

Ok so been scanning MIL-HDBK-17 with reasonable success, but we are trying to avoid developing/inventing a technology to inspect such a thick laminate. Hence why I thought I’d drop this thread, see if you guys knew anything. So if anybody can think of a mobile and reliable method I’m still all ears.

SWComposites said that a 787 or A350 wing is done with ultrasonic inspection, or pulse echo ultrasonics. Are those methods only used for the thin skin surface/plank portion of the wing. What happens when they come to thicker sections where a spar may join?

Ok, so to those who want to know what it is………… unfortunately I’ am unable to say. Apologies to wktaylor and moon161. But what I can guarantee is that I work for an aerospace company, and this component is regarded by many as a cutting edge technology. Hard to believe when it’s GFRP I know! Interesting comment by moon161 about the wind turbine,…… I guess they use thick laminates.

 

[SWComposites]

"a 787 or A350 wing is done with ultrasonic inspection, or pulse echo ultrasonics. Are those methods only used for the thin skin surface/plank portion of the wing. What happens when they come to thicker sections where a spar may join?"

TTU C-scan over the whole areas is used in the factory. For in-service damage evaluation, pulse-echo ultrasonics will have to be used; how well this will work for very thick areas somewhat remains to be seen - its going to pose some challenges to the aircraft operators - but then those areas are not likely to get damaged much beyond the outer plies.

No matter what you use you are going to have to develop reference standards over the range of thicknesses to calibrate db loss with porosity level and defects. Its going to take some development work, so don't underestimate the level of effort you will need. And don't wait until the first production part comes down the line!

SW