FEM

Payam Soltani's picture

Effect of geometric parameters on the stress distribution in Al 2024-T3 single-lap bolted joints

By: M. Keikhosravi, RH Oskouei, Payam Soltani, A. Atas, C. Soutis

Purpose - The main aim of this study is to investigate the effect of geometric variables on the stress and strain distributions as well as non-linear deformation behaviour of aluminium alloy 2024-T3 single-lap bolted joints loaded in tension.


Roman_A_Pochinkov's picture

Free FEM-pack development for everybody

Dear All! If it will be interesting
for you please look at my FEM-pack FASTRAN. This software was developed for
dynamic analysis of the thin-walled shell-type structures and includes:
preprocessor (only for view early-developed FEM-models), processor (fast sparse
solver) and postprocessor (for view calculation results). Your opinion will be
very interesting for me.


Gyanender Singh's picture

weird error in Abaqus

Hi,

I am encountering a weird error in ABAQUS analysis. Their is no information in the files about why this error occurs, the execution just terminates all of a sudden. Following is the error:


Fellowships and Ph.D. position available: Analysis and modeling of the mechanical behavior of 3D nanoparticles superstructures

Colloidal nanocrystals (NCs) form a family of highly advanced building blocks suitable for large scale assembly of novel high-complexity 1D-to-3D superstructures. Their properties and inter-particle interactions, nowadays, can be highly controlled by tailoring their size, shape, composition and surface functionalization.

In this context particularly innovative appears the possibility of studying and modeling the mechanical behavior of single branched NCs structures, and analyzing how this behavior reflects on the mechanical behavior of more complex 3D assembled superstructures, such as single macrostructures (micrometric interlaced superstructures) and thin/thick films (from randomly to close-packed ordered).


PhD student recruit (Composite materials, Korea)

It is pleasure to announce that there is an
opening for students who want to join a PhD course or combined master + PhD
course (Going to directly Ph.D. course without master thesis after B.S.) in
Department of Aerospace Engineering, GyeongsangNational University, South
Korea.


Need recommendation of PhD courses

Hi I am a PhD. Student at Aalborg University at Department for Mechanical and Manufacturing Engineering in Denmark. In short my PhD project treats modeling delamination damage in laminated fibrous composite structures under quasi-static and cyclic loading.


Coupling FEM and Monte Carlo

I wnat simulat rollong process. Mteral deformation is simulated by FEM and i want simujlate microstructure evolution by KMC method. Do any one have experience in this field (coupling FEM and KMC) ?


Coupling FEM and Monte Carlo

I want simulat micro strucure evolution in metal fromind, e.g. rolling. To capture grain growth or refinement, i use MC method and rolling process simulate by FEM method (ABAQUS). Do any one have experience in this field?


saberelarem's picture

A new parallel sparse direct solver: numerical experiments in large-scale structural mechanics parallel computing


 The main purpose of this work is to present a new parallel direct solver: Dissection solver. It is based on LU
factorization of the sparse matrix of the linear system and allows to
detect automatically and handle properly the zero-energy modes, which
are important when dealing with DDM. A performance evaluation and
comparisons with other direct solvers (MUMPS, DSCPACK) are also given
for both sequential and parallel computations. Results of numerical
experiments with a two-level parallelization of large-scale structural
analysis problems are also presented: FETI is used for the global
problem parallelization and Dissection for the local


Ajit R. Jadhav's picture

Open House: Can you define FEM in one line?

Can you define FEM in one line?

If yes, what would it be? And, in that case, permit me a second question: How?

 

...Really interested in knowing what the members of this community think (of this matter), if they do...

 

--Ajit

[E&OE]

 


Manoj Krishna Majumder's picture

Simulation of single pass rolling through ABAQUS.


Water waves simulation with Abaqus

Hi everybody,

 

I want to simulate water waves using abaqus. I want design a good reef, in order to improve the waves to surf.

 

I'm Abaqus user (plasticity, elasticity, heat transfer...) but I never simulate water an less waves. Can someone help me or give me some indications to start???

 

 

Thanks a lot


Reconstruction of Saved Stiffness Matrix from ADINA

Hi,

I have saved the global stiffness matrix generated by ADINA. the format of data stored is like below:


tigrorybka's picture

Seeking a postdoctoral position in computational mechanics / applied physics / ultrasonic engineering

I am very interested in a postdoctoral position in computational mechanics, ultrasonics, applied physics, mechanical engineering, or electrical engineering. I am proficient in FEM, FDTD, Moments methods. Experienced in ultrasonic measurements that involve ferroelectric crystals, thin films, periodic structures.  Please see attached resume.


Orthogonal Projections in Lie Theory ?

I have been studying a finite element method where rigid & elastic spatial motions are separated using an orthogonal projection (actually two: one for translations/stretches, the other for rotations/spins). Since all rigid & elastic modes are orthogonal with respect to the standard Euclidean inner product, I understand the projection's action in terms of linear algebra. However, I'd like to think about it from a Lie theory perspective. So far, I haven't found any literature discussing this topic. I'm wondering if the topic makes any sense &, if so, where I might explore it. Thanks, John.

 

After more reading, I have found the following which may help:


Dynamic Analysis of Shell Element

I have some problems with my matlab code in a 9 node shell
element each node has 5 DOFs. I found that stiffness matrix for each
element is symmetric, but after transformation to global coordinate
system, the transformed stiffness matrices and the resulted global
stiffness matrix of entire shell is nonsymmetric, where order of
transpose([k]) -[k] is approximately E-18.

Mass matrix also has
been antisymmetric after transformation and so I can't solve
characteristic equation to find eigenvalues needed for dynamic analysis.

Can I ignore stiffness matrix and mass matrix being antisymmetric without loss in accuracy? Is there any method to evaluate  eigenvalues of large nonsymmetric matrices?


Mikael Öhman's picture

Capturing wetting angles in transient simulations of fluids

Dear all,
I'm trying to simulate the transient behavior of a fluid and I'm finding it very difficult to capture the wetting angle.
To begin with, I only considering the idealized case.

The common approach is to apply the pressure load
p = 2 H γ
where p is the pressure (normal traction) on the surface, H is the Gaussian curvature of the surface, and γ is the surface energy
This load will of course always yield the same equilibrium shape for a viscous fluid, regardless of the value of γ.

Now, comparing with Young's relation, where one obtains a balance containing surface energies for every interface.


deform1's picture

FEM developer job opportunity

Scientific Forming Technologies Corporation (SFTC) is currently looking for several self-motivated and talented individuals to further develop its Finite Element based software product DEFORM™.  Please visit www.deform.com for more details.  Ph.D in Engineering with strong background in mechanics, material science, or manufacturing processes, and programming experience (FORTRAN under Windows or UNIX environment), and excellent problem solving skills are highly desirable.  Candidate should have working experiences in some of the following areas: 


Material Parameter Calibration for Johnson Cook

Hi all ... Is there a way to find/calibrate material parameters for johnson and cook material model using experimental data in Abaqus? .. As far as i know abaqus has something called as data editor with which Hyperelastic materials models can be calibrated with experimental results. If not is there any other way arround to do calibration of material parameter with abaqus.


Ajit R. Jadhav's picture

Mohr's Circle---When Was the Last Time You Used It in Your Professional Engineering Work?

As a consultant in computational mechanics, I currently help write some FEM-related code, and while doing this job, an episode from a recent past came to my mind. Let me go right on to the technical issue, keeping aside the (not so good) particulars of that episode. (In case you are curious: it happened outside of my current job, during a job interview.)

If you are a design engineer, FE analyst, researcher, or any professional dealing with stress analysis in your work, I seek answers to a couple of questions from you:

Question 1:


How to mesh squre block with a spherical particle inside

I have a squre block and inside it there is an sphere. I want to mesh the whole assembly. I can mesh the sphere but when i try to mesh the squre block with the spherical hole it cant mesh and says "it cant select the source and target face". I also tried to devide it into 8 parts. That helped me to mesh the sphere but i cant mesh the squre with spherical hole with that too. So please anyone can help me out.


3D Doctor Tool

Hi,

 

I hope this is the right forum to get some help for my work. 

I am looking at CT data (DICOM files) to make FEM models. To generate 3D surface/volumes for FEM, I was looking for softwares. They all are pretty expensive (4-10K USD). I have decide togo with Able Software's 3D-DOCTOR. I am lookign for some reviews or user experience or comments for this tool.

 

Thanks

Prab


Ajit R. Jadhav's picture

Wanted: Fast FEA Solvers...

Summary:

I am thinking of informally conducting a specific case-study concerning the FEA solvers. The reference problem is a very simple but typical problem from stress analysis, leading of course to the linear systems: Ax = b and Ax = Lx.

I seek advice as to what software libraries currently available in the public domain would be best to use---the ones that would be fastest in terms of execution time for the reference problem.

I have a personal and longer-term research interest with certain issues related to the solvers technologies.

Suggestions and comments are welcome!

(1.) The Reference Problem:


N. Sukumar's picture

Linear scaling solution of the all-electron Coulomb problem in solids

In this manuscript (available at http://arxiv.org/abs/1004.1765), we present a systematically improvable, linear scaling formulation for the solution of the all-electron Coulomb problem in crystalline solids. In an infinite crystal, the electrostatic (Coulomb) potential is a sum of nuclear and electronic contributions, and each of these terms diverges and the sum is only conditionally convergent due to the long-range 1/r nature of the Coulomb interaction.


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