Science method

# Finite Element Method - Science method

Discussion forum about Finite Element Method and its applications

Questions related to Finite Element Method

I wasn't aware about distributed and parallel computing and advantages they had, but now I have been informed. Hence, I would like to build a new cluster to perform heavy mathematical calculations in Matlab and Abaqus. I have never clustered before and that's why I need assistance to setup.

Current workstation I own:

Dell Precision T5400

2 x Intel Xeon 2.5 GHz

16 GB RAM (2GB x 8)

1 x Western Digital 1TB HDD 7200 rpm

1 x nVidia Quadro FX4600 768MB GPU

1 x 870W PSU

OS: Windows 7 Ultimate 64-bit

2nd WS: I can buy another WS similar configuration to the one I own

I am not bothered about OS, I am willing to cluster with either Windows or Linux. However, my software are compatible with windows 64-bit only.

deform 3D simulation with subroutine

In Abaqus, you have the option to import your assemblies made in Creo (formerly Pro/E) as one single part or as an assembly. The difference is that, when imported as a single part, no interactions are required because Abaqus treats it as a single part no matter how complex the geometry is.

But when imported as an assembly, individual parts are imported which can be assembled later on. But with this kind of import, interactions are required. However my contacts (interactions) would be defined as 'TIE" which means it is a fixed part.

My question is that for a same assembly, should my results differ from each other in different import methods? If so, then which is an ideal way to do your analysis considering importing in part mode, it is very easy to run the analysis with minimum errors?

In Abaqus when we want to define a concentrated force (CF) at a certain point but it is coupled with other surfaces/ nodes so the force is transfered to those surfaces or nodes.

Once you made a reference point (RP) and then under interactions module, you define kinematic coupling. In coupling option, when the surface is selected, the analysis solves without any problems. When edges are selected, again it solves. But when the nodes are selected, the error pops up 'too many attempts made for this increment'. Why?

Any ideas or suggestions?

In Abaqus there is something called 'Global CSys' and then the user is allowed to make several others according to the model and requirements to define forces and other things. However, whenever you solve an analysis, the default result shown in Visualization Module is according to the Global CSys even though your BCs and Materials and other things defined using the new or custom csys. We need to change the csys from Results > Options.

Is this correct? Or there is no need to change the CSys from results > options. The results vary very slightly but it's a bit confusing.

Any advise or comment?

Because fillet reduce stress concentration in shaft without changing its profile.?

I am using Matlab to solve some finite element problems and I want to accelerate my codes using GPU. I want to use the Cusp library using Matlab but I don´t know how can I do it. I know that creating .cu files I can use Cusp, but I want to use Matlab to not lose my previous code made in Matlab.

Finite element of welding process

I am unable to find elastic constants of Glass Fiber and Epoxy Laminate. Can anyone list them WITH REFERENCE please. I require all 9 constants which include elastic moduli (E1, E2, E3), Poisson's ratios (v12, v13, v23) and shear moduli (G12, G13, G23).

The laminate can be manufactured either from hand layup process or vacuum assisted resin transfer molding technique.

Abaqus, Ansys and Patran/ Nastran

I have used a lot of software during my degree and professional work and I know it depends on what you are trying to solve determines the advantages of a particular software. Hence, this question is not about which software is better.

I am trying to solve a very simple composite problem. I have a circular plate subjected to 70 bar of pressure. The plate is made of E-Glass and Epoxy through hand layup process. 50 plies of 0.5mm are used to make up the thickness of about 25mm. The plate is bolted (25 bolts equally divided).

Model: shell

Boundary Conditions: Pressure applied on the face, bolts = encastre.

Mesh: Tet/ sweep fine mesh

Why am I getting different results in Ansys Multiphysics 14.0, Abaqus 6.12 and Patran/ Nastran 2012? Am I doing something wrong?

For example: Max. Disp. in Abaqus 6.12 = 1200mm where as Max. Disp. in Patran/ Nastran 2012 = 3400mm

I have to model a semi-elliptical crack with singular meshing in 3D.

I am able to create half model. But I want a full model with the crack (as my loading is antisymmetric). Hence, I use the reflect command and reflect the volumes with mesh.

After reflecting, I am trying to merge the common nodes in the crack plane, leaving the nodes from the crack region, so as to get a crack.

While merging, I get error- data corrupted, Negative jacobian matrix error. When I plot the error elements, I see the singular elements along the crack front.

Experts I am a novice and not sure if this is the correct procedure.

Do you know anybody who works on a flexible beam with moving mass by using matlab program or simulates this problem in a finite element software such as ansys, abaqus or patran?

What are the likely problems if we leave the large deformation option ON while using FEA tools?

I am trying to develop a 5 sided element as a part of my Masters thesis. Works are going on. But I don't know will it be an useful work for the science society.

Numerical modeling of super conductor

Is it possible to get the coordinates of all integration points in an element in ABAQUS UMAT?

I know that it is possible to get the COORDS of one integration point, but my UMAT (based upon mechanism based strain gradient crystal plasticity) requires that I must have the COORDS of other integration points as well in the same element.

Wanted to analyze the track system of a vehicle, can anyone suggest a method to use?

Wanted to analyze the track system of a vehicle, can anyone suggest a method to use?

I am using DSPI (Q-100 Dantec Dynamics) to validate an FE model of bone. I get similar strain patterns with both methods, but the strain values differ by several orders of magnitude. Values from DSPI are within 1 microstrain of range. Could these values be within DSPI error and not be reliable to perform the validation?

It is said in the conducting region, the solution of A and phi is unique. However, in the non-conducting region where the control equaiton is the double-curl equation whose kernel is non-trivial and thus the solution of A is not unique. As a result, how to make A unique there?

I would like to ask the users of FEM/ FEA about the topics that they believe are missing and if not missing, topics that are not discussed in great detail. Also the topics on which FEM/ FEA users would like to see books or research on?

Are the users of FEA packages happy to get help from 'Help' integrated in the software or would like a summarized version of that help so they can find what they need instead of clicking links upon links just to find out a simple definition?

When we are solving any problem in FEM and we end up with either positive or negative eigenvalue. Is positive eigenvalue representing a stable system and a negative eigenvalue representing an unstable system? Or can even a stable system consist of negative eigenvalues? Or vice versa?

I am working with structure meshes in Matlab and I want to check if my program is ok, then I select Comsol because is't easy to learn, but I can't find how to built a structrure mesh in this software.

Does any know how to built 3D structrure mesh in Comsol 4.2a?

I want to use capillary heat exchangers as heat exchangers for cooling a greenhouse.

I performed a simple 3d analysis of a beam (5x5x50) with steel properties (E=206e3 and v=0.33). As I decreased the element size, the results drastically changed. The changes are recorded in the excel sheet.

Why is the stress increasing exponentially?

Which region should we label 'safe or acceptable'?

Given metal electrodes contacted with weak concentrations of bulk ionic fluids, I am searching for a finite element code proven to be capable of 3D modeling of the electrochemical double layer presented with low amplitude multi-frequency electrode excitation and extracting both real and imaginary components of impedance. 1D and 2D solutions would have very limited usefulness. Analyses may exceed 2 million elements in domains that are geometrically complex.

I am using axisymmetric modeling to simulate indentation and the indentor is an analytic rigid body while the workpiece is a 2D deformable body. I am using ABAQUS 6.12 version and did displacement controlled test. Both indentor and work piece are modeled as axi symmetric. When I do the indentation, I get an unwanted reaction force along the perpendicular direction to the loading axis (RF1) which is high compared with the reaction force along the loading axis. I imposed encastre boundary condition for the bottom of the work piece and Y axis symmetric boundry condition for the workpiece axis as well as to the indentor. Could you please help me whether there are other things to be satisfied to get rid of that RF1 component?

I am trying to model this region using the finite element method, since I have done this for a cavity in a pipe. I mainly want to promote my modeling skills but I have really serious problems with the mentioned equations. I would appreciate it if someone could help me with them? Is there anyone out there?

I am starting research on coupling a neutronic computer code to a TH computer code to perform full physics in nuclear power reactor calculations.

Want to compare FEM results to gain confidence.

ANSYS CFX is a commercial Computational Fluid Dynamics (CFD) program, used to simulate fluid flow in a variety of applications.

Vector Fields from Cobham, used to simulate electromagnetic vector field .

Give your personal opinion for others to read.

We consider the order of cycle or transpotion but is there any book that will give idea of order of permutation.

When we are specifying the transient analysis method in ansys mechanical Apdl using 'TRNOPT' we are specifying the methods FULL, reduced,mode superposition and variational technology method.

Can any one help me in under standing what this means.And what is the difference between these methods

I am working on vibration suppression of cantilever beams using Eddy Current Dampers. I want to model it with any Finite Element software, so that I can compare my experimental results with it. Which software is best to use for such an analysis? Where do I begin?

I am working now on the grain drying with CFD simulation using Comsol and I need to start with one kernel simulation for moisture transfer during drying. This is the first time for me to use the Comsol. So, How can I start?

How can I simulate an infinite tip and what is the length of your model?

When working with hyperelasatic materials in any FEA software, we need to select FE models such as Ogden, Van der Waals, Yeoh, Mooney-Rivlin, etc. And I also assume that you know that hyperelastic materials can handle 600-700% strains when stretched. FE Models are required to match the experimental results with minimum errors. In my case, the Yeoh 3rd degree model fits reasonably well.

I am trying to identify that the YEOH (3rd Degree) FE model falls in to which category of strain percentage. What I mean is that the 3rd Degree Yeoh Model is acceptable in which strain ranges?

I just started to work on a human brain activity modeling in order to find a new model of sources, in order to solve the forward problem in EEG/MEG with a finite element method. Do you know the recent news in this field?

In fluent, I always used to get the error of Divergence with AMG solver. Can anyone please let me know what is the pecularity of AMG solver & settings

The sequences are as follows:

A. Do the estimation using FEM analysis and validate with experiments

B. Do the experiments and validate with FEM analysis

Most of the studies I read show that the 'A' sequence is usually practiced. I did a study, however, on validating previous experiments, which had been done by previous researchers using FEM. When I did that, I encountered large errors/differences between the FEM and the experiment. What judgement I should make? Are the FEM models the problem or must the experiment be done again to ensure it is following what the FEM analysis estimated? This is a general question related to research ethics and an inquiry about what has been missed during the experimental tests.

How can we raise the limits of integration for a triangular element in cylindrical coordinates in FEA? How are the limits in the radial and tangential direction?

What kind of special module is to be required for this and how can I model this?

In COMSOL, there is a database that includes properties of common materials. What if my material is not in it?

Hello,

I would like to know if somebody is dealing with this kind of simulation. I did not find any studies concerning this particular subject in CFD. My main issue is to know the forces acting in the human body when it impacts the water. Since I did not find anything more similar, I'm just trying to make a correlation with the slamming studies for boats, but too many assumptions must be made, and I'm afraid I'm not being too precise...

Can anyone help me by telling me some reference or ideas?

Thank you very much

Hi friends,

What is the element formulation used for PLANE42 element in ANSYS software? Please let me know if anybody of you know about this. Thanks in advance.

In CFD while analysing a problem ,adequate knowledge of these softwares is essential.

Optimization

hello friends,
i have following optimization problem;
c1-f1(x1,x2,....,xn)=0
c2-f2(x1,x2,....,xn)=0
.....
cn-fn(x1,x2,....,xn)=0
c1, c2,..., cn are constants. x1,x2,...,xn are variables. and f1, f2,...,fn are outputs of a sutructural system (let's say displacements at some points). I want to find the values of x1, x2, .., xn providing the equations listed above. I use matlab. is there any algorithm or example which i can use? can optimization toolbox of the matlab provide this?
thank you

Hello everyone I wish to do research work in the variational formulation of annular fins..

Hey,

I'm modelling a tall stack (37.5 m high) and the main loading on it is wind load, as shown here : http://courses.cit.cornell.edu/arch264/calculators/example2.4/02.jpg . I want to model the acting wind pressure but my problem is that when I apply Pressure acting on Area in Ansys it applies it normal to the area of the stack and this is not right, the wind pressure acts in one direction only on the cylindrical surface of the stack as shown in attached picture.

I wanna know how to apply this type of load in Ansys 13.0 .

Thank you very much for your help.

Best Regards,

Omar Eladel

I'm doing my master's thesis and I need some information on how to model a wall-slab connection. I need to model reinforced concrete with the connecting reinforcement. Are there any tutorials on how to do this? I've never used ANSYS before, but I'm familiar with other FEM software. Thank you!

I am a final year student of mechanical engineering. I am pursuing a project in fem analysis of annular fins considering both thermal stresses and loading conditions by considering it as a cantilever. I want to have a variational formulation for this case. Can anyone please help me out??

ANSYS and PYTHON TKINTER

Hello Friends,
Is it possible to implement GUI applications written in Tkinter into Ansys? Ansys has capability of written Tck/Tk applications. Tkinter is a library of python with Tcl/Tk GUI features, and easy to code (writing a GUI application in Tkinter is easy and fun). Any idea on the subject will be so much appreacited.

i am just completed my under grad and in post grad i want to know about the

book that will help me to make soft ware choosing elements i have completed

APPLIED FINITE ELEMENT ANALYSIS LARRY J.SEGERLIND...

Strain Hardening of material in ABAQUS

Dear engineers,
I am modeling some structures with ABAQUS and I want to know how can I introduce the strain hardening of steel materials with two main properties (yeild & Ultimate point).
In some papers it is refered to "Plasticity" and "isotropic-kinematic hardening" which I did not pass these courses.
I was wondering if you give me some information about this problem.
Sincerely
Azimi.Mohsen

Abaquas is the best software which i have ever seen to analysis the displacement and deformation of different nodes.

Has anybody modeled a model with reinforced concrete pattern in ANSYS 13? I find it absolutely different from 12 Ansys...

What is the "pressure" in field output stress component?

Hi everybody,
ABAQUS
I do not know what is "pressure" in field output list exactly.(S11,...,Pressure,..)
is it equal to "sqrt(2/3*I2)" where I2 is the second invariant? in this page:
http://www.engin.umich.edu/class/bme456/ch2stress/bme456stress.htm
i was wondering if somebody would tell me about it.
Sincerely

I am an undergraduate Mechanical Engineering student, and I want to learn FEM since it is not in our undergraduate curriculum and I wand to know how to learn it and which sciences I must have studied to start learning FEM and how to start it ?

Thank you :)

Modeling Concrete By ABAQUS.

Hi,
Is there someone who knows about modeling a concrete element in abaqus?
I have been thinking about CFT(concrete filled tube columns) and I would need sb's advice.
Sincerely

Volumetric Locking is exhibited by incompressible materials such as rubber having poisson's ratio near or equal to 0.5 resulting in an overly stiff response. The overly stiff response is depicted in figure below.

If some material is there then please forward to patel_am@yahoo.co.in

If some material is there then please forward to patel_am@yahoo.co.in

Is Ansys the best software for analysis of rubber materials..? Can anyone please comparison with software s such as Solid Works and Autodesk Algor.

There are certain advantages of FEM over BEM and vise versa, one can certainly take the positives out of both and merge them together. Is there any implementation of deriving Green's utilizing FEM? Is there any interest of such implementation in industry?

I have the boundary conditions in a fin but I don´t know how apply the neumann condition (k*dT/dx when x=L it´s 0)

For example, if I attack a problem by Finite Difference Method, could I also do with the finite element method?

I need tutorials explaining how to perform a wrinkling simulation of thin membranes

I will be grateful for help

Best regards

How can I calculate orthotropic properties for RCC in order to use it for composite structures in ANSYS?

I'm surprised and a bit confused that I read somewhere that Young's Modulus doesn't affect the results in linear analysis. The writer of this statement said to try on two different beams, with all conditions the same except the material. I tried on two beams, one aluminium and the other steel, and noted no significant difference in stress intensities.

I've studied in FEA that we have a stiffness matrix which has Young's Modulus in its equation. I'm surprised about the effect of Young's Modulus in Linear analysis in ANSYS. If this is so, then how can we differentiate two linear analysis on two different materials?

I would like to simulate a actuator made of silicon rubber in Ansys. How do I determine the constants that need to be feed? On what parameters does these constants depend on?

Can someone suggest a basic book for finite element analysis relating to health?

Anybody with good knowledge of Ansys classic interested in joining hands with a research scholar in Kochi for journal paper in Mechanical Engineering?

I am working on bolted joint in composite structures. The joint under consideration is a single bolted joint. The bolted joint is loaded in double shear i.e. there are 3 laminates, the center laminate is pulled along the length of the laminate and the other two laminates with an end tab is fixed betwen them just to avoid bending.

Can anyone recommend a resource for Topology Optimization module in ANSYS? I haven't found any book which contains "enough" info about using ANSYS in TopOpt.

Thanks!

I have two options of software: ANSYS and Abaqus.

I want to learn FEM but I am not able to choose the software. Please help me with reason and your experience.

Diameter of shaft - 39.96mm

Diameter of bearing - 40.00mm

Also I wand CFD analysis for the same and Matlab coding

I'm working on modelling of solar dryer (natural convection type) in ansys 8.0 ,but feeling difficult to apply boundry condition. Can anybody help me?

Is there any way to transfer the transient displacement function to forced periodic solutions?

Hello, I need to apply finite element method to predict the heat and mass changes during grain storage in silos using CDF ansys. the problem is how I can make a prouse media like the grain bulk?

Una herramienta que muestre cual es la actualidad o el estado del arte de este tipo de software en la actualidad muchas gracias.

In many dental studies, the analysis of stress, strain, and displacement of tisues under applied forces shows the immidiate (momentary) effect of the force application, but they lack the ealuation of the time effect.

Usually forces fade by time, & also some biological responces occurs (compression leads to bone resorption, while tension leads to deposition). Also, sutures (lines between ones of the skull ) can be opened under forces applied for some duration.

Is there a way to simulate te effect of time in such cases?????

It is for a project on evaluating spring back in sheet metals and involves non-linear analysis

thanks everybody actually i was a PG student doing my research work on 3D analysis of a laminated plate using FEM in the process got a doubt whether an analysis has to be carried out separately for fracture or not. And also is there any compulsion in going for fracture while analyzing a plate or else just finish at calculation of stresses.

is it necessary to go for fracture for calculating stresses in a laminated plate or is there any other method available for calculating stresses without fracture using 3D Finite element analysis

I am modelling an extended end plate steel connection with ABAQUS. Here is my question; what should be the interaction type with end plate and and column? Surface to surface or node to surface? Also what should be the sliding formula, small sliding or finite sliding?