Computational Mechanics Forum

Hello,

I m trying to simulate a model which involves two identical shell surfaces where their lower ends cannot move and a pressure is applied on them.

The positive pressure closes the gap between the shells and a contact occurs between them.

My probelm is that when i m trying to use varying pressure the model doesnt run while it is running for a pressure defined by 'ramp'. In any way both pressures are about the same magnitudes.

The mode of calculation is 'Static General'.

Thx a lot in advance

Dear all iMechanicians ,

Since several days I am trying to simulate a granular material very similar to sand. The uniaxial compression test performed to the material shows a nonlinear elasticity behavior during the unloading curve.

The goal is to fully reproduce the behavior of the material with a nonlinear elastic model when the material stress-state is inside the yield surface and the plastic behavior with a multilinear isotropic hardening law. The yield surface would be given by the Drucker-Prager-Cap criterion.

Hi,

I have a thermo-mechanical constitutive model for polymer and want to implement it in ABAQUS through two user subroutines namely UMAT and UEXPAN but I dont know how to use them together. Also, in UEXPAN, I need to pass in the strain tensor as information but I dont see 'STRAN' variable in the list of variables passed in to UEXPAN in Abaqus documentation. Does anyone know answer to this?

Thanks,

Mandar

I have come across a material which has a higher failure stress in compression than in tension. The elastic limit is the same in tension as well as in compression.Both the tensile and compression tests (experimental tests I mean)  have been carried out at the same strain rate –please correct me if I’m wrong, I presume such a behaviour is termed as "pressure" dependent behaviour.

Hi to all of you!



I have problems about dampings.



I have used Msc.MARC to simulate a Hopkinson bar experiment. We usually use a

"numerical damping" in these analysis.

As you know, MARC is a implicit FEM and it takes a lot of time to complete each

simulation.

So, I want to use Ls-Dyna, but I have the problem of damping. In Ls-dyna, we use

the Raylegh damping: there are 2 coefficients that multiply the matrix of

stifness and mass.

Is there any relation between these two kinds of dampings?

Hello All!

I'm study about shell and i need some ebooks to read. Coud you here give me some? Thanks a lot.

Hi, everybody!

I have some problem with understanding of shear ratio history (srat) in UDEC.

Here is the description of this function in UDEC manual: "srat - ratio of shear stress to shear strength at contact".

If I take the value 1/srat then I should normally get the value of factor of safety (FS) for shear condition, since this value will be the ratio of shear strength to shear stress at contact. But shear displacement history (sdis) shows that there still can be some shear displacement in case of FS=1/srat more than 1.

Dear Forum members

  Does anybody have idea about a publication on the rigorous Finite Element treatment of a plate on surface of elastic layer (infinte horizontally). Existing methods obtain the foundation stiffness by inversion of a flexibility matrix. For an elastic layer the flexibility matrix is approximately obtained by Steinbrenner's assumption. Is a more rigorous fexibility matrix for an elastic layer available?