Computational Mechanics Forum

Hi,

I want to try abaqus progressive damage model to simulate steel failure in Abaqus. I read the manual, and found that progressive damage model would be sufficient for my purpose. As I am quite new to damage modeling, I do not know how to determine parameters for shear failure or ductile failure or jjohnson cook model. Also, I would like to use damage evolution as well. Could anyone suggest me some typical parameters for steel (both damage initiation and damage evolution).

Thanks.

1. Hi,

Elastic strain is any strain that takes place before exceeding the yield stress. However, it is important to note that, for hardening materials, elastic strain is increasing during post yield also.

Now,my question is- even though if I unload my specimenin the labortory and calculate the strain removed during loading- how can I calculate the elastic strain at a level of load following yield?

Because, the elastic strain is increasing following yield too- how can I know how much it is increasing?

Hi,

I've been learning how to implement material models using UMAT in ABAQUS and I have

some simple questions:

I've been trying to implement the viscoelastic models in the paper:

Formulation and implementation of three-dimensional viscoelasticity at small and finite strains

1) The variable "STRAN" in UMAT corresponds to the strain at time $t = t_n$ or $t = t_(n+1)$,

       Let us consider a rectangular domain with discontinuity(holes whose surface are insulated) meshed randomly with quadrilateral elements. I am trying to solve unsteady nonlinear diffusion equation in that domain. Which is the best numerical time integeration scheme/method? The results are always oscillatory for methods I am using.

Hello

Problem description: There is a simply supported(roller supports) shell element I-beam. There are lateral bracings too. All of this boundary conditions belongs to the Riks step(always last step in analysis).

Question: I have implemented triangular residual stresses by SIGINI subroutine, but I'm not sure what boundary conditions set up in preliminary equlibrium step. Should I include all of the lateral bracings in this step or maybe only roller support? 

Thank You 

Hello,

  I need suggestions/advice regarding quick starting point for getting strains (Green-Lagrangian) from displacement vector field defined over nodes of a triangular mesh ?

I understand that this is a well established theory, however, I was wondering if I can avoid reinventing the wheel !

Can someone help  me regarding which would be the fastest way to get there ( compute strains )? 

Thanks, 

Hi all,

I am writing a umat for FEAP.  My UMAT needs the physical/global coordinates of the Gauss Integration point upon which it is being run.

is it possible to get the Physical/Global
coordinates of the Gauss integration point upon which the UMAT
subroutine is being run ?

Hi,

I recently statrted using ABAQUS. I started writing subroutines few days ago and I have written few basic subroutines such as Istothermal Istoropic material. I need to come up with a Umat code for thermoelectric material. I dont know where and how start working on it. I will be really helpful if someone could share their ideas with me.

Thanks,

Deepak 

Hello,

Hi everybody.

I use ADINA. After my static analysis, I plot bending moment distribution over a cross section. Is there a way to find total bending moment at that section in ADINA software? I think some integration is required to do that, but have no idea how to manage it with the software. Surely, there are similar operations in ANSYS, ABAQUS etc.

Any help appreciated.

Riza.