How to define Anisotropic Material in Abaqus?

[Vijay1988]

Hello Everyone,

I am working on a project where in I want to define anisotropic (composite) material in Abaqus software. I found that to define anisotropic material we need to input 21 different values (D1111, D1122, D2222, D1133,......., D2323)in the Abaqus. These 21 values must be the elastic constants of an anisotropic composite material (say wood). These 21 elastic constants forms the compliance/stiffness matrix of the anisotropic material. However, I am not able to calculate these 21 elastic constants. Is there any formula to calculate these values or is there any source available where can I get experimentally determined values of wood?

Your help is greatly appreciated.

Thank you in advance.

VijayH.

 

[IceBreakerSours]

Given how you have framed your question, I sense that you have not done your homework. How can you begin to successfully model something without knowing the material constants? I bet there is tonnes of data on all kinds of wood. Have you searched online? Have you searched through Google Scholar for peer-reviewed publications on this subject matter? If you have not, you must.

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[Vijay1988]

Hi IceBreakerSours,

Thank you for replying. I just gave an example of wood as an anisotropic material. Wood is not matter of my interest. I just want to know how to calculate all those 21 constants for any composite material. Also, I have been thoroughly searching on google about calculation of 21 constants. What I found was just the compliance matrix/stiffness matrix. But nowhere I found the information on calculation of each value. I also checked abaqus user guide. There also it is not clearly defined how to input these 21 values to define anisotropic material.

If you have any information regarding these then I kindly request to share it.

Thank you.

 

[ebdoep2]

If your material is truly anisotropic you need all 21, sorry. To say how to calculate them would be like saying I have a modulus now I want to calculate my Poisson's ratio for isotropic material. You simply can't do it, it takes two independent values for an iso material, just like it takes 21 for an aniso.

Now if you start going with orthotropic or lamina you can easily find equations to get from some of the 21 constants to another just like you can do E=2G(1+v) for iso. But then you might as well just use the Abaqus input for ortho,lamina,etc. instead of full anisotropic.