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Polyrethane

Polyrethane

(OP)
Hello

Iam working with polyrethane material. Ido not know the behavior of this material. Can any one help me to introduce its parameters in Abaqus. Thanks a lot.

RE: Polyrethane

I believe you mean polyurethane. Unfortunately for you, this material can vary from very low stiffness elastomer to high stiffness thermoset. You will need to provide more information about your material source and your processing technique(s) to get better answers.

RE: Polyrethane

(OP)
Hello

Thanks for your answer. Unfortunately i have not a lot of nformation about the material. All that i know is that i will use it as the material of elastomeric ligatures used in orthodontic devices.

RE: Polyrethane

afefdridi,

Your first step should be to obtain molded test slabs (in order to cut tensile test specimens) or molded tensile test specimens of the subject material. Once you have them design a tensile test to cover the expected strains and determine whether you want first pull test data or long term test data. Once you have the data, I would recommend using the Marlow model within Abaqus, prepare your data for Abaqus (see the manuals for details).

Manufactures and associated test labs, including your own, will not test slow enough or capture enough data in order to create a useable FEA material model. Quality tests are typically very fast and compare a couple of points which do not accurately describe the material's stress/strain properties.

I hope this is helpful.

RE: Polyrethane

There should be a lot of info about polyurethane on the internet. Several of my engineering handbooks have sections on plastics. Machine Design publication releases on a yearly basis a publication that summarizes technical info. on materials that included plastics. Manufacturers of plastics will also provide technical info on their plastic products.

RE: Polyrethane

I used to work for a company that compounded all their own rubber including polyurethane. There can be large differences between one compound and another based on what is added to the base polymer to modify properties, add color, or to affect cure. A common method to distinguish one compound from another is to use hardness but I have personally tested two compounds with the same hardness and obtained two significantly different stress/strain curves.

It is useful to follow chicopee's advice in order to build and test out your model while you wait for the slabs to arrive and be tested. But unlike elastomers like Nylon, which are branded, polyurethane and other rubbers differ based on who compounded them. Therefore in my opinion if you want accurate results there is no substitution for testing your compound.

Good luck.

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