Computational Mechanics Forum

I am attempting to implement the St. Venant Kirchoff model in Ansys using the USERHYPER subroutine. I have expressed the strain energy density function in terms of the isochoric invariants of the right Cauchy-Green strain tensor (I1,I2) and elastic volume ratio (J). I would like to confirm the expression for the strain energy and its 9 derivatives (see below). I would also like to also clarify the differences between the linear elastic model w/large displacements and the St VK model.

 Thanks

Hello.

     Could anyone tell me how to  achieve the basic unsteady diffusion equation (Fick's second law) of some solute for a given Abaqus model by UMAT & User-defined field in Abaqus? or some other subroutines?

    Is there any reference good for this problem ?

  Thanks very much!

Dear Marc specialist users Colleague:



I am developing an user material subroutine (HYPELA2) in Msc Marc (Marc Mentat2012.1.0, Windows platform, 64bit).

I am trying to make a write inside in Hypela2.f routine, but it doesn't work.

I have used the file number unit 6, for example,  write(6,*) ' Hello' , but

no any results in the standard output file. Otherwise, the Hypela2 works properly.

Does anyone have any suggestions how can I write out any data from Hypela2.f?

Thanks.



Leslie

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Hello Everybody

I am in need of help in including multiple load step options in my c program which is a fem solver for contact(2D).

I do not understand how  to go for second load step after the 1st one.

Its not clear for me what all i have to do, one thing i know is updating the nodal locations.

Please help me on this or guide to the place where ir can get help.

Thank You

Hello everyone !

I'm new to abaqus and have a problem with the shell-solid assembly. I want to model a shell element (plate) clamped into two solid elements (parallelograms) on its top and bottom edges.

I've tested different possibilities to do my assembly (shell-solid coupling, merging the geometry or the mesh when assembling the two elements) but none of them work. There's always a problem whis the definition of the elements' properties when I submit the job.

Does anobody have a solution ?

Hi, all,

I recently encounted a big question regarding to the temperature dependent UMAT case. 

I used the UMAT for non-isothermal elasticity as followed. The DDSDDE calculating part is not shown here.

You can see that I output  ETHERM(K1),EELAS(K1),STRAN(K1),DSTRAN(K1) at the beginning of the code.

And this UMAT also saves ETHERM and EELAS to state variable array.

I am studying the response of a bridge in MATLAB, and have successfully retrieved mass and stiffness matrices from Abaqus using the following keywords:

*Step

*Matrix generate, STIFFNESS, MASS

*Matrix output, STIFFNESS, MASS, FORMAT=COORDINATE

*End step 

This gives matrices on a mathematical form, very well suited for use with MATLAB.