poisson ratio polyurethane moldings

[siscogj]

Anyone know what poisson ratio value range I should be using for FEA purposes? Cannot find on efunda, etc.

mil-m-24041c

Thanks

 

[patprimmer]

Have you tried the raw material manufacturer. They should be the best source grade specific data.

Regards

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[Pud]

Due to the creep behaviour of plastics, stress is heavily dependent on strain rate, so a value for Poisson's ratio is generally not specified. If you look at a typical plastic data sheet, you should see that some parameters are actually specified at a defined strain rate (e.g elongation before break is usually at 50mm/s - sometimes other rates are given.

As Pat suggested, talk to the material supplier and they should be able to help.

Cheers


Harry

 

[siscogj]

I tried talking to the material manufacturer, but the part that I am analyzing was made in the early-mid 80's and the company is unable to locate and provide the material data sheets.

I understand the creep-rate effects for a constant load, but for a one-time impulse-loading situation it seems there should be a poisson's rtion value applicable for polyurethane.

 

[patprimmer]

It will probably be called an apparent Poison Ratio. That's what they do with e mod which is also prone to creep.

Bayer Materials or Lenxis or whatever they call themselves now should have data on a similar grade. 20 years ago they literally published truck loads of technical data.

They invented PU and were always considered the market leader re technical service.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[siscogj]

Do you have a website or phone # for Lenxis?

Thanks,

 

[patprimmer]

Was the "whatever they call themselves now" a clue.

Regards

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[Demon3]

That's Lanxess, used to be Bayer.

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