Accelerated testing

[grob]

Does anyone have any experience of Accelerated testing of water absorption of composites. I have heard of ASTM D570 24 hr boiling water tests and the like. Does anyone have any experience of how these tests correlate to long term immersion.

I guess what I am asking is how do you perform accelerated testing of new composites in water.

Thanks

Gareth

[Dutch Peter]

I would imagine 24h is accelerated enough compaired to 15 years in service.
Since the ASTM and ISO codes are used for quit some time now to determine the performance of composites in water, I conclude the learning curve is well established.
But maybe I have to much confidence in these codes.

From what your asking, I sence you don't have to much confidence in this way of testing!? So, what are you proposing as alternative?

[grob]

Dutch Peter,

Since the ASTM and ISO codes are used for quit some time now to determine the performance of composites in water, I conclude the learning curve is well established

I think you are telling me what I need to know in that sentence.

Its not that I don't have confidence in the tests, its more that I have little experience of them. I am looking to use a new process. The manufacturer of the composite has boiled a test piece in water for 72 hours to prove its suitability for long term use in water, and having no experience of this test I was enquiring as to how valid it is.

Thanks

Gareth

[Dutch Peter]

Gareth,

In that case I have to add that the boiling test is not the only test there is, depending on the material, there are several more tests to determine the suitability of a material:

- tensile test (wet and dry)
- shear test (wet and dry)
- 3-point bending test (wet and dry)

also fibre orientation is important and may result in these tests being done in every single fibre direction.
If you have a couple of days to spare I'll let you know the standards that are used to obtain a Lloyd's type approval.

Regards

[grob]

If you have a couple of days to spare I'll let you know the standards that are used to obtain a Lloyd's type approval.

That would be great, Thanks

[Dutch Peter]

Grob,

Sorry it took so long, had trouble finding the right book.
Test standards for fibre reinforcements, laminate testing:

Tensile: ISO 3268
Flexture: ISO 178
Compressive: ISO 604
Interlam. shear: ISO 4585
Water obsorption: ISO 62
Glass content: ISO 1172

Will try to get the ASME codes too.

[Dutch Peter]

Gareth,

It was not ASME but ASTM:

Tensile: ASTM D297-94
Flexural: ASTM D790
Absorbtion: ASTM D272-01
Shear: ASTM D273-61

Good luck,

[grob]

Thanks

[Dutch Peter]

Sorry it had to take 2 months

[gonzo]

The downfall of the boiling test, is that all marine epoxies fail it. However, epoxy built boats perform well.

[Dutch Peter]

That's right Gonzo, I guess the test is to determine which epoxy fails last. That one you should use for your boat!!!

[gonzo]

At boiling temperature, 212 farenheith 100 C, all marine epoxies fail. There are some specialized high temperature epoxies though. My point is that we should find tests that work with some of the modern adhesive currently in use. Both Loyd's and ABS fail the WEST system.

[Herman]

I just tossed some foams into a UV tester which also does a condensation cycle. Let's see what happens. I have the details in another thread about pourable foam.

Unfortunately I do not have a tensile tester. If someone has one for sale, or knows of one, please let me know.