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Old 28th Mar 2006, 17:57
  #22 (permalink)  
tallsandwich
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Learn from the Marine experience - no thanks...

There is not much that the marine industry can offer regarding composite knowledge. Sure, the marine sector makes good R&D contributions regarding materials and manufacturing processes but as a previous poster mentioned, this is not the challenge.

Forget anything that is done for whacky one-off racing yachts; when you are considering a product that will be used with high frequency for a long service duration, you need to look at the commercial marine sector for such products - and there is very little there that would advance the aircraft industry.

For a composite (FRP) ship or boat, the design gets certification to do a certain task for 25 years and thus remain insurable within acceptable statistical limits. The design factors used in the stress analysis are in a different league to the aircraft industry (design it then double the size in case someone drops a hammer on it). Product testing is governed by the intended loading conditions (i.e. combination of speed and sea state) and as a result almost impossible to accurately predict.

In service, the marine product gets unpredictably bashed between two fluids, one of a relatively very high density (water) and one of a very low density (air). You simply cannot take an FRP ship or boat and talk about 'loading cycles' to the structural engineers in the same way you can with a plane. The stress cycle of a boat going between two ports is not so predictable in the same way as an aircraft going between two airports.

The marine FRP inspections are relatively crude and mainly manual. Access to do this, when compared to an aircraft, is simple. Analysis result is either it (the composite) has delaminated or it has not, whether due to moisture or trauma. No one in the marine industry can tell you that this bit of composite can survive X number more loading cycles before catastrophic failure, let alone define the macro loading cycle with sufficient accuracy.

Given all the above, the marine engineering community is hardly well positioned to deliver anything of real significance.
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