ELEMENT STIFFNESS MATRIX

[tulbo]

Hi,

I am using USDFLD and a solution dependent field variable to specify the variation of elastic modulus (fieldv=pressure=s11+s22+s33 in my case). Then how is the element stiffness matrix computed at beginning of each load increment? The material properties are a function of the field variable which in itself are solution dependent. I have read some text on this but it is not very clear to me. Can anyone help?

Thanks in advance

 

[Mustaine3]

It's an iterative scheme. The solver has a similar task, when you make your material temperature dependend in a thermal analysis.

 

[tulbo]

Hi
Thanks for your reply. My confusion was because after using the subroutine, the stresses are computed correctly at the integration points but the strains are not. I thought that in FEM the order of solution is (i) nodal disp> strains> stresses. So, I was wondering how the stresses are correct but the strains are not.