functionally graded materials

[A. M. A]

hi
I need help in writing a subroutine to represent continuously graded materials so that the young's modulus and the Poison ratio are variable with the location.

 

[FEA way]

The simplest way would be to use distribution feature but this allows you to define spatially varying elastic properties only on element-by-element basis. To define them based on coordinates you would have to use USDFLD/VUSDFLD subroutine and set field variable dependence of elastic properties.

 

[A. M. A]

Can you give an example, please and thanks for the help

 

[A. M. A]

I mean an example for USDFLD subroutine and how can represent the variety in two variables, young's modulus, and Poisson ratio

 

[FEA way]

Yet another simplified method (without the need for subroutine) would be to set temperature dependence of elastic properties and assign temperature distribution to the model via analytical field. Of course this will only work in case of regular stress analysis (without thermo-mechanical coupling).

But if you want to use USDFLD, check this thread for reference:

https://www.eng-tips.com/viewthread.cfm?qid=418895

Abaqus documentation chapter about USDFLD will be also useful.

 

[A. M. A]

if I make the material properties depend on the temperature. I suppose that temperature values are fake because there is no thermal analysis. can I put any values of temperature and without changing anything in my model like partitioning it as you know there are some researchers suggest discretize the model and assign the required temperature to each region. I find some difficulties in implementing that in my case where I'm trying to calculate SIF in FGM by using a 3point bend specimen with an initial edge crack if you can show me the way I will be Grateful