So Abaqus uses some incremental formulation of nonlinear mechanics, right? This
is not available in sfepy (and I have no experience with that). You probably
cannot reformulate the update routine to the total Lagrangian formulation?
r.
On 07/09/2013 09:13 PM, Hadi Seyed Hosseini wrote:
> Hi,
>
> Thank you for your replies. Abaqus UMAT is in fact a material update
> routine providing an interface to implement the constitutive equations of a
> specific problem into the FE software Abaqus. In this subroutine, the
> inputs are strain tensor for the increment and the strain tensor for the
> beginning of the current increment, the deformation gradient tensor etc.
> The UMAT routine then updates the stress tensor and the corresponding
> material Jacobian for the end of the current increment at each integration
> point. The UMAT routine is normally written in Fortran.
>
> In my case, I deal with a highly nonlinear elasto viscoplastic material
> behavior.
>
> Best,
>
> Hadi
>
> On Monday, 8 July 2013 19:03:42 UTC+2, Hadi Seyed Hosseini wrote:
>>
>> Hi,
>>
>> I am quite new in the software and find it both useful and at the moment
>> confusing.
>> I have a user material (UMAT) written in Fortran for Abaqus and I would
>> like to know if it is possible to wrap it into sfepy.
>> As the software is highly object oriented, it is not easy to follow the
>> existing examples, so that one can create a new
>> problem and solve it using sfepy. All I need is to find out how to obtain
>> the strain tensor or the deformation gradient tensor
>> so that I can pass it to my material update routine to update the stresses
>> and the material Jacobian tensors and at the
>> end of the routine pass it to sfepy to calculate the force and the element
>> Jacobian matrix.
>>
>> I will appreciate any hint on this issue.
>>
>> Thanks.
>>
>> Hadi
>>
>
