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Soil Modeling

Hi

Please help in modeling the soil.

I  modelled soil as non linear springs in Abaqus?Standarads and analysed the pipe behavior for hydrodynamic loading.

I am currently planned to model the pipe-soil interaction with soil as an 2D or 3D element along with contact properties. Give me suggestion or methods how can i model soil.Suggested reading materials.I have gone through the abaqus documentation.It tell that soil can be modeled as 2D or 3D.I am really confused which one to use. 

Please give me some steps in creating soil and pipe model .

 

another practical optimization problem (IOSO vs Genetic Algorithm)

Dear Colleagues,

Let us continue viewing the efficiency of the application of various optimization methods on practical optimization problems.

 

Abaqus, element removal

Hi everybody,

 is there anyone who is familiar with element deletion or removal to predict crackopening in RC member model in ABAQUS?

I've made a 2D model of RC beam in abaquse with brittle cack properties and brittle failure but I could not get any result. Can I make my model by concrete damage plasticity and using abaqus standard to apply element removal?

I will really appreciate anyone who helps me to solve my problem.

 Thanks in advance

venapa's picture

Dynamics of AFM cantilevers

Hi everyone,

I am looking for papers on the dynamics of AFM cantilevers in contact with non linear material samples. In particular, I am interested in forced armonic vibrations of the catinlevers.

I have seen many papers on intermittent contact (or tapping) which has a number of additional problems w.r.t. the contact mode.

Many thanks for the help.

Pasquale V.

Element remoal

Hi

I am intending to make a concrete member model to investigate crack opening in tension zone. First, I wanted to use crack propagation model and could not get good result. So, I think that I can do it by using stress/strain principal failure and element removal.
I've tried to fiure out how I can apply this method in my model.
Is there enyone who has experience in this issue? Could you please help me in this matter?

 

Zartasha Mustansar's picture

Abaqus Result viewing

Hi everyone 

Can anyone advise on how to select stress values at specific points in a model once the job is executed?

I am interested to extract the stress values from specific points (nodes) in a model. 

Many Thanks.

Zartasha 

zappalorto's picture

Notch stress distributions

Dear all,

this is for all people interested in notch analyses. 

In the links below you can find some recent works of mine about linear and nonlinear stress distributions for different kind of notches under torsion.

Hope they will be useful to someone:

http://www.springerlink.com/content/5v536n0026v42586/?p=e7c8da446d524e75...

asit_rathod1's picture

Slope of The Non Linear Stress Strain Curve at Proof Stress

Dear All

Hi..

Can Any body tell Me The calculation of the E_t Tangent And E_s Secant Modules VAlues of the Stress Strain curve?...

i had go through some of graphs but i dont get it?..it will be help ful to understanfd the E_t And E_s?..

i had values of Stress and Strain and also a Stress strain curve available..

Plz do need ful..

 

Finalists for 2010 Robert J. Melosh Medal Competition Announced

Seven finalists and three honorable mentions have been announced for the Twenty-Second Annual Robert J. Melosh Competition for the Best Student Paper in Finite Element Analysis. The seven finalists and their current institutions are:

Marcial Gonzalez, Caltech

Ming-Chen Hsu, University of California San Diego

Alejandro Ortiz, University of California Davis

Jay Oswald, Northwestern University

Rashmi Raghu, Stanford University

Phanish Suryanarayana, Caltech

membrane locking and CST trangle

I often read on books that linear triangles do not have membrane locking for large deformations of plates/shells. I completely don't understand how this is possible. If one uses the well-known CST, stretching is measured as the increase in lenght of each edge of the triangle. Then, in the limit of the membrane stiffness going to infinity, clearly the solution cannot approximate any bending-dominated state, but rather it will be always rigid on general meshes (i.e. Minkowski theorem for convex bodies), allowing at most bending about few lines on very regular ones. What am I missing?

Arash_Yavari's picture

Structure of Defective Crystals at Finite Temperatures: A Quasi-Harmonic Lattice Dynamics Approach

In this paper we extend the classical method of lattice dynamics to defective crystals with partial symmetries. We start by a nominal defect configuration and first relax it statically. Having the static equilibrium configuration, we use a quasiharmonic lattice dynamics approach to approximate the free energy. Finally, the defect structure at a finite temperature is obtained by minimizing the approximate Helmholtz free energy. For higher temperatures we take the relaxed configuration at a lower temperature as the reference configuration.

Fracture Mechanics

Taxonomy upgrade extras: 

UEL for 2 or 3D element types

Dear iMechanica users,

I would like to write a UEL for 2 or 3D element types used in large deformation, but, I really have little experience in it. Is there any UEL example apart from the simple 1D example in Abaqus manual and the complicated one written by Eugenio (XFEM)?

Thanks,

Hadi

volinsky's picture

Summer Job for Students in Europe: International US-European Joint Study of X-Ray Optics Thermomechanical Stability and Control

Summer Job for Students in Europe: NSF-sponsored International Research Experience for Students (IRES)
International US-European Joint Study of X-Ray Optics Thermomechanical Stability and Control

 

Bo Liu's picture

Exact solutions for the free in-plane vibrations of rectangular plates

All classical boundary conditions including two distinct types of simple support boundary conditions are formulated by using the Rayleigh quotient variational principle for rectangular plates undergoing inplane free vibrations. The direct separation of variables is employed to obtain the exact solutions for all possible cases. It is shown that the exact solutions of natural frequencies and mode shapes can be obtained when at least two opposite plate edges have either type of the simply-supported conditions, and some of the exact solutions were not available before.

Constitutive equations for membrane element

Choose a channel featured in the header of iMechanica: 

 

Hi all,

 There are two poisson ratios for membrane element in Abaqus.  One is for the material and the other one is "effective section poisson ratio", which can be set to zero to fix the thickness of the membrane.  Does anyone know how these two Poisson ratios work in the constitutive equation of a membrane?

 Thank you very much!

 Yasheng

UMAT to VUMAT

 

Hello ,

 

I am a relatively new user to ABAQUS , and i am trying to figure out a way ( if there exists ) to convert a model defined in ABAQUS / Standard to Explicit for conducting impact testing.

 Now i have figured out most of the model apart from the material defination. The previous model has a User defined material , and i need to convert it to a VUMAT.

 

Is there any way to perfrom this operation ? Or do i have to  just re-code the enitre material , as there are just too many differences in the way both are defined ?

Von mises and Tresca stress criterion

Difference bewteen Von mises and Tresca stress citerion. Any good references?

Thank you

 

pandi's picture

Bridge

I am new for using abaqus , can anybody tell me how to apply the moving load on the bridge by using abaqus

Which package suits for fatigue analysis?

I would like to simulate fatigue analysis to know the fatigue life, can any one guide me to do the same. and please specify which package suits for the same.

Thanks

Balaa

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