I am using exponent Drucker-Prager model at the moment, is there anyone can tell me where the follow exponent D-P eqation comes from originally?

(σ e)(σ e)=λ(σ_t)(σ_t)-3(λ-1)σ_mσ_t

Where λ= is hydrostatic stress sensitivity parameter and equal to σ_c/σ_t, σe is effective stress, σ_m is hydrostatic stress, σ_c, σ_t are stresses under compression and tension, respectively.

I am doing my master thesis on crash simulation of plywood (7 layers-orthotropic material) structures in buses using explicit LS-DYNA FE program. I would like to include failure in my model. Right now I am working on Mat_054_55 (MAT_ENHANCED_COMPOSITE_DAMAGE…..material model from LS-DYNA material library).

Mat_054_55 allows me to get failure by defining anyone of the following parameters,

In a recent rapid communication (see attached paper), using principles of pattern formation, we expose some simple stategies to reliably produce perfect long range order in self-assembling systems. Most self-assembling systems exhibit short ranged order. This imperfection is detrimental to several practical applications. It is almost always possible to produce perfect patterns in small domain sizes but self-assembly over a larger areal span results in defects.

I'm trying to model a composite structure with shell 99 element in Ansys.

I set the thickness and material no. in real constant and prepare an orthotropic material property for that. While ploting the result, as I expect to get the stresses among layers different from other points, but the result is a kind of uniform isotropic graph.

I don't know if any setting other than real constant and material property should be done to get a true result or not. and if I'm true then how can I read the true result.

I will appreciate any help.

I would like to know the difference between Effective Strain, Effective Plastic Strain and Effective Failure Strain.

Hi,

     Thanks for the earlier feedback. I was able execute the user subroutine (UMAT) along with *.inp file only to land into new type of error message:

fatal error lnk1112: module machine type 'IA64' conflicts with target machine type 'X86'

Can somebody please help me to understand what this error means and how to overcome this monster.

I have already installed intel fortran compiler, and microsoft visual studio for windows. 

As always thanks for the much needed help. 

For more than 15 years, carbon nanotubes (CNTs) have been the flagship material of nanotechnology. Researchers have conceived applications for nanotubes ranging from microelectronic devices to cancer therapy. Their atomic structure should, in theory, give them mechanical and electrical properties far superior to most common materials.