Science topic

ANSYS - Science topic

Explore the latest questions and answers in ANSYS, and find ANSYS experts.
Questions related to ANSYS
  • asked a question related to ANSYS
Question
3 answers
Hi,
I get an error saying that my model is not sufficiently constrained when I connect solid element having 3 degrees of freedom to a shell / beam element having 6 degrees of freedom.
Is there a way elements with different degree of freedom can be connected in ANSYS APDL?
A rigid link or something?
Relevant answer
Answer
Dear Zeinah, please try the code below for defining coupling between the nodes that belong to solid and shell elements. I wrote the code for all DOF, however, you can use what you need. Let me know any problem with this issue, good luck.
!======= CODE BEGIN =======
n=1      ! arbitrary Constraint Point number  n1=11   ! master node  n2=12  ! slave node
cp,n+1,ux,n1,n2 cp,n+2,uy,n1,n2 cp,n+3,uz,n1,n2 cp,n+4,rotx,n1,n2 cp,n+5,roty,n1,n2 cp,n+6,rotz,n1,n2
!======= CODE END =======
  • asked a question related to ANSYS
Question
1 answer
What softwares can i use to make assemblies for FEA other than 3 matic and mimics?
I'm doing a Fea for a human skull but my mimics license will expire soon and i desperately need another software
Relevant answer
Answer
Google "Open Source Finite Element Softwares", then you will find many nice FEA Free Softwares.
As a personal experience, I suggest you try "Code Aster" with "Salome Meca"
  • asked a question related to ANSYS
Question
2 answers
The asphalt material is DBM VG40. I have determined its elastic modulus.
Relevant answer
Answer
This is the command (APDL) that can be used to define the material. Polymer is the name selection.
mat_num=2
MP, EX, mat_num, 0.5E+05
MP, NUXY, mat_num, 0.49
MP, DENS, mat_num, 1E-09
TB, EXPE, mat_num, 1, 10, GMODULUS
TBTEMP, 22
TBPT, DEFI, 0.1, 70000, 34300, 0
TBPT, DEFI, 0.2, 90000, 53100, 0
TBPT, DEFI, 0.5, 110000, 75900, 0
TBPT, DEFI, 1.0, 150000, 119000, 0
TBPT, DEFI, 2.0, 200000, 170000, 0
TBPT, DEFI, 3.0, 225000, 207000, 0
TBPT, DEFI, 10, 400000, 396000, 0
TBPT, DEFI, 100, 1700000, 1700000, 0
TBPT, DEFI, 500, 4000000, 3600000, 0
TBPT, DEFI, 9000, 20000000, 14000000, 0
TB, PRONY, mat_num, , EXPERIMENTAL
CMSEL, S, Polymer, ELEM
EMODIF, ALL, MAT, 2
ALLSEL
/solu
rather I suggest to use ANSYS Workbench ... there you can insert material property using GUI (engineering materials) or using APDL Commands.
  • asked a question related to ANSYS
Question
3 answers
I performed transient structural analysis on a shaft geometry as a result I got the amount of thermal deformations. shaft geometry has different diameters on the surface, how to calculate the increased diameter or thickness for different areas of shaft i.e. after deformation.(without using code)
@
Claudio Pedrazzi
Relevant answer
Answer
I realized that you mentioned this question to Dr.
Claudio Pedrazzi
, I haven't seen any answers or comment from him for about a year and half, I hope he is doing well. He got many experience in Ansys specifically Ansys APDL. We miss him a lot here in RG. Thank you so much for your kind email, it is my pleasure that my answers here in RG helped you in the past.
Going back to your question, I think Dr. Victor J. Аdlucky already provided a very good guideline and this is the only thing you can do, if you don't want to use any kind of coding for that.
You can do the following steps for calculating radial deformations.
1. Insert a Cylindrical coordinate system in the center of your geometry.
2. Insert a directional deformation contour. Select the surface you are interested in and adjust the coordinate system to the one you just made. Then adjust the Orientation to reflect "X Axis".
3. Extract the result for this contour. Extracted results show you the radial deformation which you can add/subtract it to/from the original dimension for calculating final dimension.
Also, You can do the same thing with Cartesian coordinate system, however, you need to extract the result for X, Y and Z direction and then calculate the resultant vector.
Hope this answer helps.
Thanks,
  • asked a question related to ANSYS
Question
3 answers
I have already made a 3D printed PLA part using FDM method and now I want to do a FEA(FEM) simulation of tensile test. Can anyone guide me which software I must chose and what is the procedure?
Relevant answer
Answer
using Ansys for instance, you simple create your models by the same geometry as the ones you used to print, then input same material properties in the element set up stage. you can choose various meshing styles. does your model have any form of stress concentration feature?
  • asked a question related to ANSYS
Question
2 answers
I am trying to develop a goniolens and meshing it to the surface of the cornea of the eye model
Relevant answer
Answer
Hi Pratik Bhala!
Here is a simple code for curve element modeling
CSYS, 5 ! Activate cylindrical coordinate with Y as axis of rotation
Rbr=50;
PI=3.1416
Lapp1=20
ELE_SIZE=0.5
K, (KPmax+115), (Rbr-3.25), ((Lapp1*180)/(Rbr*PI)), -0.3
K, (KPmax+116), (Rbr-2.75), ((Lapp1*180)/(Rbr*PI)), -0.3
K, (KPmax+215), (Rbr-3.25), (((Lapp1+Lbr)*180)/(Rbr*PI)/2), -0.3
K, (KPmax+216), (Rbr-2.75), (((Lapp1+Lbr)*180)/(Rbr*PI)/2), -0.3
K, (KPmax+315), (Rbr-3.25), (((Lapp1+Lbr)*180)/(Rbr*PI)), -0.3
K, (KPmax+316), (Rbr-2.75), (((Lapp1+Lbr)*180)/(Rbr*PI)), -0.3
ASEL, NONE $ LSEL, NONE $ ESEL, NONE
LARC, (KPmax+115), (KPmax+315), (KPmax+215),
LARC, (KPmax+116), (KPmax+316), (KPmax+216),
LESIZE, ALL, , , (Lbr/ELE_SIZE), , , , , 0
L, (KPmax+115), (KPmax+116), 2
L, (KPmax+315), (KPmax+316), 2
AL, ALL
Analysis of Distortion-Induced Stress and Retrofitting Technique of Curved Twin I-Girder Composite Bridge | SpringerLink
  • asked a question related to ANSYS
Question
3 answers
Hi,
Do anyone know how to add a custom (Chemical as well as physical properties, such as, viscosity, density, ratio of solution, etc.) fluid type in ANSYS?
Relevant answer
Answer
Go to the FLUENT material database and click add -> new materials and provide all the details. Then you can use the material when defining the particular portion of your domain. Physical properties of fluids and solids are associated with named materials. These materials are then assigned as boundary conditions for zones.
When you model species transport you need to define a mixture material, consisting of the various species involved in the problem. Properties will be defined for the mixture, as well as for the constituent species, which are fluid materials.
For example :-
These files can be created in a text editor and saved with a .scm extension.
(New
fluid
(chemical-formula ....)
(density (constant ....[like for air 1.225])
(premixed-combustion 1.225 300))
(specific-heat (constant . 1006.43))
(thermal-conductivity (constant . 0.0242))
(viscosity (constant . 1.7894e-05)
(sutherland 1.7894e-05 273.11 110.56)
(power-law 1.7894e-05 273.11 0.666))
(molecular-weight (constant . 28.966))
)
(New
solid
(chemical-formula ....[suppose as al ])
(density (constant . 2719))
(specific-heat (constant . 871))
(thermal-conductivity (constant . 202.4))
(formation-entropy (constant . 164448.08))
)
You can also follow video tutorials on YouTube, and instructions are available in the ANSYS FLUENT user manual.
  • asked a question related to ANSYS
Question
2 answers
Hello,
I am currently working on an axial pump. The original geometry didn't perform as well as I expected, so I plan to improve its performance. But all the ANSYS tools I tried either didn't work or didn't give me control over the variables I wanted, so I decided to use C code.
Is there any way to link the C code to Ansys CFX?
Thank you very much.
Relevant answer
Answer
That depends on what you are trying to do. CFX has a C++ interface for reading and writing meshes. The solver has a user fortran interface, and the whole thing can be scripted using various text files (session files, CCL etc) so you can automate CFX by writing these text files. Writing text files can be done in just about any language.
first, the pump parts are made using Bladegen, then imported to Turbogrid for meshing, after that setup, and CFD-post.
I'm using genetic algorithms, so all the process should be done automatically
In that case it sounds like you want to write something which generates the input command files for Turbogrid, CFX-Pre, Solver and CFD-Post and then calls the command line to start those packages. This can be done in C or just about any other language. It is just generating text files and then running executables from the command line.
  • asked a question related to ANSYS
Question
4 answers
Dear Researchers :
Recently I asked an official quotation (with all the requiered concepts) from ANSYS and from COMSOL to implement the same type of License and the same set of modules, the scheme of the License are not exactly the same , but very close ,
For both software I'm interested in being able to solve applications with the Structural Mechanics Module and the Electromagnetic Module
But in general, If I place both final prices in the same footage, I realise ANSYS is always more expensive (at least today) than COMSOL (roughly between 35 - 40 % more)
Does anyone with experience in this may know one of the reasons why this is so ?
Regards !
Relevant answer
Answer
Since I got more experience with scripting, I want to share my opinion from scripting point of view.
I found ANSYS more interesting than COMSOL because of its outstanding scripting capabilities. Depending on the module you want to use, ANSYS either uses JavaScript (e.g., DesignModeler and Mechanical) or IronPython (Workbench interface, Fluent etc.) in the background. In addition, Ansys provided APIs in IronPython programing language for almost all its modules (e.g., DesignModeler and Mechanical) which makes automation very easy. I mean you are not going to be limited to go with only one programming option and different gateways are provided for programing.
whereas, in COMSOL you will be limited to APIs provided in Java only, which is fine too.
This is my two cents and hope other people can share more great opinions from other perspectives.
Thanks,
  • asked a question related to ANSYS
Question
1 answer
I want to find out the volume of material remove by wire edm process for that i have to find out crater radius and depth.
If file will extract in stl file format than i can easily measure the radius and depth in solidwork.
please suggest me what i have to do.
If any other method which is accurate and precise than please let me know.
Relevant answer
Answer
Very interesting question. Extracting STL file from APDL is a bit tricky and difficult. You can use this macro to generate STL file which works with both TET and HEX mesh. I think you used HEX mesh right? A big thank goes to Eric Miller from PADT who wrote this awesome macro.
After you exported the STL file you can use the following method to calculate the volume of the STL geometry.
1. Open a new SpaceClaim geometry and then open your .STLfile.
2. Use shrinkwrap function located in cleanup set of Facets.
3. Select imported facets.
4. Click on preserve feature (You need to set the gap size to reasonably lowest possible value).
5. Then click on complete.
6. Now you can convert created shrinkwrap to solid.
7. After you transferred the STL to solid then you can measure the volume using the mass properties in inspect set of measure.
Hope this answer helps and please recommend if it worked for you.
Thanks,
  • asked a question related to ANSYS
Question
2 answers
Hi,
I want to connect two nodes by using a multipoint constraint element MPC184 ( rigid beam / rigid link)
at first, i tried connecting both nodes by a line and then mesh the line and give it MPC184 element attributes but I cannot create a line from node to node on ANSYS. Only from keypoint to keypoint.
The attached image shows what i mean.
how to fix that?
Relevant answer
Answer
Hello,
As you work with a script in M-APDL environnement, I think it's quite easy to fix your problem :
* First, define an element type associated to the MPC184 element -> ET,10,MPC184 for example, in order to associated the MPC184 element to the element type n°10
* Then, adjust the key options in order to choose your MPC behaviour -> KEYOPT,10,1,3 for example to say that the keyopt n°1 for the element type n°10 is 3 / if the element type n°10 is associated to the MPC184 element, that means that you ask for a slider element behaviour (help MPC184 command line for help on MPC184 element and keyopts)
4/ as NODE1 and NODE2 exist, the sequence to define an element between NODE1 and NODE2 is ($ for new line character) : TYPE,10 $ E,NODE1,NODE2
(active the n°10 element type,which is already associated to the MPC184 element, with the appropriate keyopts, and then define an 2-nodes element between NODE1 and NODE2.
MPC184 is not associated to any geometric entity, that's why you can't mesh a line with a MPC184 element. You have to define it directly with the nodes.
  • asked a question related to ANSYS
Question
5 answers
Hello all
thanks alot for your support
I got up with a doubt , for simulation normally we use ansys or abacus of tensile testing . But when it come to polymers tensile testing which software need to be used. as the infill pattern will change the effect of fracture , what software we need to use for simulating tensile testing of specimen's. if we go with ansys the dog bone will be treated as simple structure but not infill parameters. can some one clarify my doubt please
need software suggestion to do testing simulation.
Relevant answer
Answer
Just have a view on this link. It will help you u gain an idea in the Abaqus software
  • asked a question related to ANSYS
Question
3 answers
I want to model resistance spot welding in ANSYS APDL. How to model heat generation, which happens in the highest amount at contact of two sheets? How to model electrical contact resistance or conductance?
Relevant answer
Answer
What I have suggested is the general procedure for implementing the heat generation due to contact resistance which always works. I have not gone through the coupling feature of the solid element you have mentioned. In order to know why the program is not able to implement effect of contact resistance, you will have to go through the help and 'theory manual' where they might have explained how they are considering contact resistance, if at all.
Additionally, heating also takes place due to bulk heat generated by bulk resistivity of the material and during the later part of the heating process when the contact resistance drops considerably, it is the bulk heating which generates the heat.
  • asked a question related to ANSYS
Question
1 answer
Recently, I was simulating the tutorial file "SIEngine_PortInjected_AMG_Tutorial.ftsim". After the simulation completed I got some results. I have some basic questions that make me doubt the solver, maybe I am wrong.
The questions are as follows:
  1. 100% combustion efficiency. ( On which basis combustion efficiency is calculated? ) I calculated fuel mass multiplied by LHV which is greater than the chemical heat release rate. How is that possible? This seems like an ideal case.
  2. UHC is almost zero. How is this possible?
  3. Fuel Mass per Engine Cycle is showing  2.07651E-002 [g], whereas in the excel sheet iC8H18 concentration is 2.18E-002 gram before combustion. Why there is a deviation?
  4. Fuel Lower Heating Value per g  44.00000 [kJ]. This LHV value remains the same if I change the combustion from gasoline to CNG also. I guess it may affect results also.
Please answer these questions.
Relevant answer
Answer
Combustion efficiency is an input in such cases, not an output; that is, you tell the software (or it assumes) a combustion efficiency. If you have assumed it's 100% efficient, then there is no UHC, as this is an inevitable consequence of the assumption. You need to dig deeper into the science of combustion calculations and not rely on software that somebody else wrote for you.
  • asked a question related to ANSYS
Question
3 answers
How can I measure phase difference between two points in a model in ANSYS HFSS? The model has one port that is excited by lumped port and I am using driven terminal. I want to know that is there any way that I measure phase difference between the input and another point in the model?
Relevant answer
Answer
Mahmoud Fallah خیلی خیلی ممنون بابت راهنمایینتون، حتما این روش امتحان میکنم ، امیدوارم روی مدل من جوابگو باشه.
  • asked a question related to ANSYS
Question
1 answer
i started work in simulation on iron ore pot sintering process. in this how to give sinter mix( mixture of iron ore fines + coke breeze+ dolamite fines+ limestone fines) data in ansys fluent.
Relevant answer
Answer
please follow the link to get the solution. Just put the required solid mixture in engineering data to define the mixture its a free input system.
  • asked a question related to ANSYS
Question
2 answers
Hello, this question is intended to those who have experience in designing electrical machines using ANSYS RMXprt software. I am not being able to select a material of my choice, when it comes to designing the winding of any machine. Suppose I am designing an induction machine and for some reason, I want the stator winding to be made of aluminum instead of copper. I am not being able to do that. The RMXprt software takes copper by default and I cannot find any provision to change it. Any suggestion regarding this is welcome. Thanks in advance.
  • asked a question related to ANSYS
Question
1 answer
Heloo All,
I am doing simulation about archimedes screw turbine with ansys fluent. But, the continuity do not converge. It always increasing and become floating. The boundary condition is same like the teory. Any suggestion all?
Thank you very much
Relevant answer
Answer
Did you try to reduce under relaxation factors at the beginning of simulation? If not, try it.
  • asked a question related to ANSYS
Question
4 answers
Post processing is done successfully, meshing is done successfully but when I get to the running of solutions it gives error after sometime
Relevant answer
Answer
Anoop N N Dear thank you for your valuable feedback. I will include your suggestions, will see if the things are successful. Will surely update you. Thanks again.
  • asked a question related to ANSYS
Question
3 answers
I am trying to simulate buckling phenomenon of ion source grids under thermal load in vacuum.Two grids namely screen grid and acceleration grid made of SS304 are mounted on a SS flange.The grids are electrically isolated from each other and SS flange by ceramic bushes.The inter grid spacing is maintained by brass spacers.I want to fix the grids at the bolting location so that it does not have any deflection there.A heat load of 300W is applied on the face of screen grid which faces the flange.There are no apertures in the model as it is just a preliminary study.The thickness of each grid is 1mm.
Following are my questions.
  • What kind of contact(bonded,rough,frictional etc) should i define between brass spacer and grid and brass spacer and ceramic bushes to get proper deflection results?
  • On what faces of the assembly should I define radiative boundary conditions? (Just 2 grids or even bolts,nuts, flange etc)
  • Which area of the assembly should contained the fine mesh size? Since I am using a regular 8GB desktop I am not able to make meshes <2mm element size.What is the criteria for choosing mesh size?
  • How can I know that the output by ansys is correct? (i.e the direction in which the grid buckles is right or wrong?).
I have attached picture of a sample run output for understanding.I have labelled all the components in the geometry.Please feel free to ask if you need any other details.
Thank you
Relevant answer
Answer
Hi Bharat,
Setting the boundary conditions will only be part of the solution. In the case that the grids are dished, when heated they will expand in the direction they are dished. When they are flat, they could buckle away from the heat, towards the heat, or just become wavy or a saddle shape, depending on which bolt lets the grid slip first.
You should try adding a very shallow dish to your grid model, and make sure that it buckles in the same direction as that dish when heated. (i.e. the radius of curvature of the spherical surface goes down)
-Charles
  • asked a question related to ANSYS
Question
3 answers
Working on analysis after assigning everything when I click on solve error popup saying invalid name selection how to resolve this can anyone help me out with this, please
Relevant answer
Answer
Hi, i believe you are trying to apply point load on a node.
Anasys wb by default works on geometry hence its showing yellow marking for wrong selection of named selection.
Below is the link where it shows how to apply force on nodes or elements instead of geometry:
Hope this helps.
  • asked a question related to ANSYS
Question
3 answers
I want to make a model for turbulence in Ansys. In the project a fan is used which is completely submerged in water. How to proceed in this situation ?
Relevant answer
Answer
In my case, the k-w SST model works well. The application of this model, as well as comparisons with other turbulence models, can be found in
"Simulations of the aerodynamic response of circular segments with different corner angles by means of 2D URANS. Impact of turbulence modeling approaches. Eng. Appl. Comput. Fluid Mech. 12(1), 750–779 (2018)."
If you are a beginner, you can try all the turbulence models available in Ansys and check which modeling results providing you the best validation.
  • asked a question related to ANSYS
Question
4 answers
when using streamline "surface streamline" in an area between two blocks, streamline disconnected as mention in the pic attached
thanks for your help
Relevant answer
Answer
thanks, Shino Ulahannan for your reply, first I make the part as a single body but it was difficult to be a structured mesh. so I discretize it to be easy for meshing then makes it as one body from the design modeler and complete the meshing .so does the output of the meshing operation for one body can be discontinuous?
  • asked a question related to ANSYS
Question
1 answer
Currently, I am conducting pressure based transient incompressible fluid flow in viscoelastic tube in ANSYS fluent and I would like to create an absorbing boundary condition in the outlet of the tube.
ANSYS Fluent already include non-reflecting outlet boundary conditions (NRBC) but only applies for ideal gas (compressible) flow.
With Pressure Far Field BC, it is available only when density is calculated using ideal gas law.
With Outflow BC, it cannot be used for unsteady flow with variable density.
So, the last option is using UDF in the outlet of the tube and I have difficulty applying it.
I found a thesis that similar to my research approach. (https://folk.ntnu.no/leifh/alumni/2013_Merethe_Sirevaag_Hansen.pdf)
And I would like to create such boundary condition in ANSYS fluent.
In page 27 of the thesis, under Section 3.2 Boundary Conditions, in Subsection 3.2.1, the author applied reflection free boundary condition at the outlet of the vessel. I have short knowledge of how to apply the boundary condition at the outlet of a vessel.
I am learning UDF in ANSYS Fluent, but I am not sure how to apply boundary equation (Eq 104, page 28) at the outlet. I assume it will require to use UDM but the equation require to use the volume flow rate value from previous space step.
I manage to calculate in numerical analysis but Can someone show a tutorial to put Eq 104 in UDF of ANSYS fluent?
Relevant answer
Answer
@Sandaz have you yet gotten what you want for Research?
  • asked a question related to ANSYS
Question
5 answers
What is the shell orientation mean in ANSYS APDL?
Does it mean that if I have a shell on the XZ plane then I set the orientation as 0 degrees as shown in the pictorial view
and if I have a shell on the XY plane then I set the orientation as 90 degrees?
Or does it mean something else? Like the direction of the fibers in the material?
Relevant answer
Answer
Dear @Zeinah Mohamad Elnassar,
The material orientation is used in case the model is described by an anisotropic material. It shows the principal axis of the element (for composite materials the fibres direction as you mentioned), where in shell elements a single angle is enough to describe the local orientation of the element.
  • asked a question related to ANSYS
Question
10 answers
I'm going to analysis of theorical RC beam by FE nonlinear analysis then verify the RC beam models with FEA softwares.
Relevant answer
Answer
The best FEA software is one you know how to use. You could get good results in both of them. But, if you are starting to learn any of the software, I would suggest you to learn ANSYS.
  • asked a question related to ANSYS
Question
3 answers
How can I modify strain rate effect in ansys workbench for explicit dynamic analysis..?
And what is the suitable number for this factor  
Relevant answer
Answer
If you will change the strain rate exponents in the material models then the strain rate effect will change.
  • asked a question related to ANSYS
Question
3 answers
User-Defined Function (UDF) in ANSYS Fluent to define the heat generation source of a Li-ion battery.
Relevant answer
Answer
welcome
  • asked a question related to ANSYS
Question
4 answers
I got stiffness matrix by using HBMAT, and convert it to sparse matrix.
But I don't know the order of DOFs. Cause the equation K*D=F cannot be satisfied.
K is stiffness matrix, D is nodes' deformation, F is load vector.
I need to know the order of DOFs, anyone can give me some suggestions?
Thanks a lot.
Relevant answer
Answer
Hi Xiaolin,
I am having the same problem with you. I was wondering if you have found any solutions for this.
Thank you very much.
  • asked a question related to ANSYS
Question
3 answers
In a non-linear, implicit Process (2D), I start with anisotropic Settings and three E-Moduli for the three Directions of Freedom. When I use a hardening Model in ANSYS (Kinematic Hardening or Isotropic...), will that cause Anisotropy during the Simulation-Process? Will it be taken into account during the calculation?
Thx in advance
Relevant answer
Answer
A question. Do you know how can I create a model for orthotropic plasticity in Workbench? i managed to create it via APDL code in Workbench but unfortunately, many parts are not compatible with codes of APDL in the workbench.
I need to study an orthotropic bilinear material.
  • asked a question related to ANSYS
Question
2 answers
Hello,
I have been carrying out an ANSYS Fluent CFD analysis of the system outlined in this paper:
Broadly speaking, my results are as expected for the setup and I'm very happy with them. However, I am missing one crucial aspect; the cyclone cooling effect shown in Fig. 6 is not observed in my results. I'm confused as to why this is the case. The air accelerates and swirls as expected. I have tried modelling the air using the Boussinesq approximation, as an ideal gas and as a real gas but the issue persists. Perhaps I'm not fully grasping the mechanism causing this cooling.
I'm not 100% sure the boundary conditions I set up are correct. Both the inlet and outlet are pressure boundaries with 0Pa gauge pressure. The inlet is at 300K and the backflow from the outlet is at 288K. I wasn't sure if I should set the gauge pressure for the outlet to a negative value to account for the change in pressure with altitude, or if the system deals with this. The solar flux is modelled by using the inbuilt solar loading and works as expected creating a temperature rise across the collector. Even velocities of the updraft are of the correct order according to quick calculations. I'm a bit lost as to where I have gone wrong, any help would be appreciated.
Relevant answer
Answer
I don't think this is quite my problem. There is a result I expected in my solution that I am not seeing. I can get the temperature in the cyclone it is just a lot higher than what was predicted by the literature. I tried to model air density as ideal or real gas instead of bousinesq and it didn't help and the air all 'fell down' rather than showing the expected behaviour. Are there any possible shortfalls in my BCs or material modelling that could be to blame?
  • asked a question related to ANSYS
Question
6 answers
I have built a RVE in Ansys and I know the equation of periodic boundary condition. However, I'm struggling in applying the equation in Ansys. I have read some thesis that they are using constraint equation or APDL. Which method should I use?
Relevant answer
Answer
Dear Alexander, I have more experience with Ansys Classic than with Workbench. Things can be better controlled when writing an APDL file. The mesh on you RVE should be regular so that you can create and identify opposing corresponding node positions on edges. The CE command allows you to build relations between corresponding degrees-of-freedom on such nodes (node by node). The couplings tend to destroy the banded structure of the system equations: The RVE will give you a small number of equations, but these tend to be fully coupled because of the periodicity conditions implemented. Neverthless, the RVE will be much more effecient computationally than a model including a larger number of RVE's where in the end you will have have to discuss the influence of edge effects.
  • asked a question related to ANSYS
Question
1 answer
There are various macros to define user define function to incorporate the chemical reaction but as i am dealing with the gas-liquid chemical reaction and i can not find any such category of chemical reaction in ANSYS UDF manual.... For reference I have attached a screenshot of a research article.
Can anyone please help me to define a UDF to incorporate the reaction kinetics in Ansys Fluent?
Relevant answer
Answer
I don't use ASYS software. My favorite software for kinetic modeling is COPASI.
I would write the mechanism as following
CO2(g) = CO2
CO2 + H2O = H2CO3 (the rate constant must be known)
H2CO3 + H2O = HCO3- + H3O+ pKa is known
HCO3- + H2O = CO3-- + H3O+ pKa is known
2 H2O = HO- + H3O+ , [HO-]*[H3O+] = 1e-14
MeA + H2O = MeAH+ pKa is known
The solubility of CO2 in water is low, therefore I doubt that the reaction (11) takes place.
If you have CO2 in the gas phase and the volume of the gas phase is significantly larger than that of the solution, then you can assume at under vigorous stirring [CO2] ~ constant
  • asked a question related to ANSYS
Question
4 answers
I am interested in the mathematical apparatus for this process, as well as the method of step-by-step modeling in the specified FE complex.
Relevant answer
Answer
Hi;
Please check the following attachement.
With my best regards
  • asked a question related to ANSYS
Question
4 answers
As MMCs are not available in ANSYS, i am looking to use DIGIMAT-FE for modeling and then use it in ANSYS.
Or have someone used COMSOL for the same?
Relevant answer
Answer
Dear Colleague,
hope these will help
brochure_digimat_6.0_0.pdf
  • asked a question related to ANSYS
Question
9 answers
I am modeling a bridge on ANSYS APDL using shell and beam elements. The beams and slab are connected using MPC184 (constrained element).
After I am done modeling and meshing I merge nodes with 0.001 tolerance yet I still get an error saying meshing will produce errors. even when i tried to merge all I still get a warning / error message
After Nummrg,all / Nummrg,NODE .... future commands which depend on the node to solid model connectivity (meshing, mesh, clearing, solid boundary condition transfer, etc.) may not operate properly.
My results are wrong. Is there a step that I messed?
Relevant answer
Answer
It is a “warning”, not an “error” message, so it only warns the user to pay attention because something is happening in the analysis. As far as understand, the message simply tells you that a node, which before merging belonged to only one CAD entity, after merging is shared by more than one geometrical entity – which is exactly the purpose of merge command. This was also explained very well by Naveen Bhatt.
I think that if areas are glued before meshing, nodes will be shared automatically at common boundaries. Anyway, besides this point, I have two comments:
- Why to connect shell/beams with MPC184 (constrained element)? Have you tried simply to connect them at a node? They should be compatible (i.e. same degrees of freedom);
- Why to use such small elements for the slabs? Normally, small elements should be only be used in regions where high stress variations are expected, otherwise they will increase the computational cost unnecessarily;
  • asked a question related to ANSYS
Question
3 answers
I am not sure whether to use boolean A glue command to glue the areas / lines of my model together.
OR
just use merging nodes NUMMRG, node command
My model is a static linear bridge element where the slab and railings are shell elements, the beam flanges are beam elements and the beam web is a shell element.
Beam and shell elements are connected using MPC184 rigid links.
Relevant answer
Answer
Glue Command
  • asked a question related to ANSYS
Question
2 answers
i am getting an error whenever i am running the given attached simulation on ansys maxwell 16.0.
This arrangement consists of two electromagnets housed in two coil of copper winding supplied with ac voltage as shown.
I have given excitation voltage in both the winding separately as shown and boundary condition on coil as shown.
I am using transient solution as type of solution.
Any advice you provide me will be highly valuable.
Thank You
Relevant answer
Answer
Did you enclosed the model in a vacuum space or air box?
  • asked a question related to ANSYS
Question
4 answers
I am analyzing two adjacent interconnected rectangular channel flow patterns. The image of my numerical model is attached below.
The fluent solver was pressure based, and velocity formation was absolute. The SIMPLE algorithm was used. Laminar regime was selected and energy equation was kept on. Boundary conditions were checked carefully. Inlet velocity and pressure outlet conditions were applied. Uniform Heat flux was applied at the bottom face. Solid fluid interfaces are thermally coupled. Second order upwind equations were used for energy and momentum equations. The residuals were kept 10^−5 range, and the solution was fully converged.
I have drawn a centerline inside a mini-channel for observing velocity distribution. Is my solution right? and velocity profile having zigzag is okay? if not, pls explain.
Relevant answer
Answer
I think this article might helpful for your research:
Wish you all the best luck!
KHOA
  • asked a question related to ANSYS
Question
5 answers
I'm using ANSYS Fluent 2019 with Space claim, my problem is involving moisture diffusion (therefore using Species transport). I found that my h2o can never pass through the porous zone.
I have tried varous porosity value, viscous resistance, with and without UDF of different diffusivity, and even (in space claim): shared topology or without shared topology but with contact. Do anyone know how to fix this?
Relevant answer
Answer
Take a look at this paper:
DOI: 10.1615/JPorMedia.2021025407
  • asked a question related to ANSYS
Question
1 answer
Hello,
I modelled a air cooled heat exchanger as porous media. Also I want to add convective heat transfer using radiator model in b.c(There is air flow in the porous zone). When I define the porous media, fluent automatically creat a interior-porous in internal boundary conditions and I defined this interior-porous as a radiator, but after run the calculation there wasnt any heat exchange. Do you have a any idea why its not working ?
Thanks in advance
Relevant answer
Answer
Hello,
Maybe you can uso a 3D model in solidoworks / inventor to make your analysis.
  • asked a question related to ANSYS
Question
2 answers
For my CFD simulation in ANSYS.. I need a basic understandable geometry of a membrane.... Where the process is for inorganic membrane separation of Carbon Dioxide from heated air or natural air
Relevant answer
Answer
Hi
You can try a method in ANSYS Fluent name as "porous media zone", in which you can consider a membrane as a homogeneous zone with pseudo momentum resistance and porosity. This assumption can greatly reduce the complexity in modeling real porous layers.
For reference, this tutorial will help you out:
  • asked a question related to ANSYS
Question
4 answers
hello every one , my project is about magnetohydrodynamics . i'm trying to simulate fluid flow (fluid is mercury ) between two parallel plates ( dimension : L=300mm , h=3mm) in ansys fluent , we applie magnetic field transversally ( B0=3.819T) .the flow is laminair and the fluid is incompressible , the diet is stationary.The vilocity of the flow is U=0.01m/s .
my problem is the solution doesn't converge , i tried to decrease the factor of under relaxation ,but it still the same problem . i saw that sometime the problem could be in the mesh , my mesh quality is 0.8 , is it good or i should improve it ?
Relevant answer
Answer
Check your magnetic field source term. Maybe the udf isn’t interpreted correctly
  • asked a question related to ANSYS
Question
1 answer
Hi all,
According to literature it is said that inoreder to simulate the residual stresses correctly in metal castings viscoplastic or elastoplastic creep material model should be used.
Does anyone have experience in developing such a model in Ansys?
Relevant answer
Answer
  • asked a question related to ANSYS
Question
6 answers
Dear Community,
I recently switched from ANSYS Mechanical to COMSOL Multiphysics. So far I was able to transfer my models to the new platform but I yet miss one feature of ANSYS in COMSOL. I hope someone is able to help me out.
What I am talking about is the ability to "couple" (Ansys term) nodal degrees of freedom. In my case this would mean that the displacement of any node in a set of nodes (a surface for instant) is equal and not predefined. We are using this feature to model one eigth of an pseudo-infinitesimal cube of material. Three surfaces of the cube are subject to classical mirror symmetry and the opposite surfaces stay parallel to allow for volume change. The x-y-surfaces are subject to u_z(x0) = 0 and u_z(x_n) = coupled.
In Ansys, this feature is available as the APDL command "CP". It is not available in the GUI. I need this feature primarily for the solid mechanics solver of COMSOL. If anyone knows the name of this feature in COMSOL or can recommend a workaround please feel free to answer.
Thank you very much,
Felix Schleifer
Metals and Alloys
University of Bayreuth
Relevant answer
Answer
Hello,
One way to do that is to use point probes:
1. Define a point probe on any point of your boundary of interest, for the probe expression, enter the component you wish to prescribe, e.g., u, v, or w
2. Define a prescribed displacement on that same boundary, and give the name of the probe as the value for the displacement
Best,
JBC
  • asked a question related to ANSYS
Question
3 answers
If I have a rotor on two bearings, under what conditions should I use pre-stressed modal analysis and when should I run a rotordynamic analysis i.e. using the rotordynamics options in a modal analysis?
Relevant answer
Answer
Bladed disks are much stiffer compared to to rotor and therefore, you can study the vibration of the bladed disk by only considering that part. This means you will specify a fixed BC on the disk-shaft contact surface. Define the rotational speed and do the prestressed modal analysis by including gyroscopic effects. This type of analyses can be done like this in ANSYS.
  • asked a question related to ANSYS
Question
2 answers
Hi,
I am performing a Fatigue analysis, I am referring to the ISO standards and they always stipulate to perform the fatigue tests at a precise frequency (20 Hz). I can't see in the fatigue tools a frequency option.
Is their a way to set the frequency with ansys fatigue tool ?
thanks in advance !
Relevant answer
Answer
The Fatigue Tool will report cycles to failure by default.
You can divide that number by two to get the seconds to failure.
You may set the tool to report hours to failure by inserting 1800 (or 1/1800, I'm not sure which) someplace in the tool's options.
The Fatigue Tool is described in the ANSYS Help system.
  • asked a question related to ANSYS
Question
7 answers
Hello,
I am running a simulation of a system powered purely by energy from the sun. During the daytime, the results are as expected. During the night, I expect the system to still have a large amount of motion as there should be a decent amount of heat stored in the system. However, whenever I try to run a simulation spanning 24hr, I get a floating-point error when the sun sets. Before the error, I get some anomalous data where the temperatures and velocities are way too high (out by 4 orders of magnitude or more). I really don't understand what the issue is here. When the sun sets shouldn't the solar loading just stop? Shouldn't the system just slowly use up its remaining energy until the sun rises again? Is it possible that the radiation is falling on the base of my geometry?
I think that I am misunderstanding something about the solar loading as it is this that triggers the issue. In my attempt to troubleshoot, I set up a system that was definitely stable and well defined without the solar load. Then, when a solar load was applied and I ran it in a 24hr transient simulation I faced the same issue.
Any help, advice, or a point in the right direction would be appreciated.
Relevant answer
Answer
Edward Jenks Okay, The free, open-source, Fortran90-based, modular Monte Carlo ray tracing code for concentrating solar energy research is available by contacting Professor Petrash ([email protected], [email protected]).
  • asked a question related to ANSYS
Question
6 answers
I am simulating a rectangular water channel. To validate my numerical results, I want to present a graph containing the enhancement of Nu for this channel with several Re. Then, I compared this variation with another's study where the hydraulic diameter is not the same, however, both channels are mini-channels.
For example:
pls download the paper given below:
In this paper - Under Section 3.1:
The authors validated their model with Fan et al., Ho et al, and Moraveji et al. However, their hydraulic diameters are not same. How is this comparison valid?
Relevant answer
Answer
To understand how to compare your results with an experiment or literature results, please learn the theory of Dimensional Analysis. According to this theory, a phenomenon is governed by dimensionless numbers. For example, in one case, the Nusselt number is affected by the Reynolds and Prandtl numbers. Therefore, when you compare the Nusselt numbers you get with the Nusselt numbers from the literature, you must compare them to the same Reynolds and Prandtl numbers. For the case you are comparing, you need to equate the definitions of Re, Pr, and Nu between your case and the case in the literature. For example, if the Re and Nu numbers are defined by involving the hydraulic diameter in the literature, then you calculate your results at the same Re and Pr.
Good luck....
  • asked a question related to ANSYS
Question
1 answer
Possible post-processing step for plotting the configurational force vectors in APDL or any other supporting softwares.
Relevant answer
Answer
Dear Mr. Singh,
have you found out in the meantime how to plot the configurational force vectors in ANSYS? If not I would have an APDL code for work around to get the plot.
With best regards,
Sandra Baltic
  • asked a question related to ANSYS
Question
2 answers
I am developing user material subroutines for anisotropic damage in orthotropic material in ANSYS APDL. So I would like to delete the elements when the damage of an element reaches a maximum value or full damage. I am storing the time history of the damage variables as internal state variables. I know the EKILL command is used to kill the element when the element reaches a certain condition. But I don't know how to access the state variables of each element during the solution phase from the APDL script and execute the EKILL command when the state variable i.e., the damage reaches a maximum value. So it would be really helpful if someone can help me with this.
Relevant answer
Answer
Dear Arun
you should bring your criteria in a table and select elelmtns by using ETABLE commands, and then use EKILL for selected elelments:
ETABLE, Lab, Item, Comp, Option Fills a table of element values for further processing.
  • asked a question related to ANSYS
Question
3 answers
I am trying to simulate the Charpy test using Abaqus, could someone specify the boundary conditions that should be taken and which model should be followed.
Should I use the Johnson Cook's model?
How much time can the simulation take on a 4 core laptop?
I tried reducing the meshing to reduce the simulation time, what effect will it have on the results?
Relevant answer
Answer
Dear pearl
it is better to used ANSYS LSDYNA or ANSYS AUTODYN instead of ANSYS.
  • asked a question related to ANSYS
Question
4 answers
Hello everyone,
I am presently working on project which alredy created by previous students on ansys workbench, where my work is to automatize set of variables in batch mode to genarate the data.
To do that i craeted small project, recorded python journal file and edited them to feed set of values to parameters eg:Young's modulus and results are printed out to text for each instance by running ansys in batch mode.
reference : https://github.com/kpestov/ParametricStudyAutomation (i follwed almost similar)
The example project worked perfectly fine and achived what i wanted but its not working with my actual projects where if i run the sript there will be no errors/warnings instead, at each iteration it prints out same output which is wrong.
My questions are
1. Does the warnings (not errors since the problem solved with all components with green marks, image1) which are genarated in workbench can cause problem to brakedown the script??
2. I found out that i can see some journal files in session file which named crashed but i cant really able to figure it out whats the problem, do you think these are main source of error for script to brokedown? (image 2)
3. Does anyone faced this problems or experience pleae share your thoughts.
Thank you and I eagerly waiting for your suggetions and helpful answers.
Relevant answer
Answer
Regarding the journal files, these files automatically be generated by ANSYS and it shows what was running in your Python program. I think part of the program that is feeding new numbers to the parameters is not working properly. Therefore, you are getting same results as you explained in your question.
Recording Python macro is a good idea to start developing your code, however, it is not going to fix all the problems and you need to check your code line by line to see where is the issue. Another important thing is that, the moment either Mechanical or DesignModeler is opened, then workbench is not able to record anything.
Attached please find a little script that enables connecting Excel to workbench. This code shows how to define a parameter, feed a parameter and extract final results in a Python macro.
Hope this answer helps.
  • asked a question related to ANSYS
Question
1 answer
Hello,
I tried to perform a response spectrum in my structure. However I can't proceed because of the error (ERROR: Data file file.db does not exist for RESUME). My modal analysis run successfully but I am getting this error when performing response spectrum. How can I fix this error?
I am currently using ANSYS 2020 R2 student version.
Thanks
Relevant answer
  • asked a question related to ANSYS
Question
2 answers
I want to model steel fiber distribution but I don't know how to design a math equation.
there is any way to improve this area by suggesting books or papers thank you so much.
  • asked a question related to ANSYS
Question
4 answers
I am performing a 3D transient analysis on Fluent. I want to capture only certain contours/vectors/pathlines at every iteration. Not all. For the moment, I have selected the option to save at every iteration, but the saving takes a lot of time, and increases the total time for the analysis. Is there a simpler way, where I can save only the parameters I want at every iteration, to speed up the process?
Thanks
Relevant answer
Answer
Sorry for the late reply.
Saving a set of outputs with a sensible interval is adequate for building animations. In my opinion, there is bound no need to save EVERY time-steps.
If you want to observe a particular flow-time, you have to set your saving interval so that the auto-saved output file may coincide with the flow-time you want to know its velocity vectors.
Truly
  • asked a question related to ANSYS
Question
2 answers
I'm going to perform an ANSYS explosion due to Combustion Modeling and simulation, this area of research is totally new for me. Any advice or idea or any direction to start research??
Relevant answer
Answer
首先要保证网格没问题,简单的几何模型可以用结构化网格,然后随便找本《fluent从入门到精通》的书,按照上面燃烧的算例计算就行,注意油气比,油气比不合适可能得不到好的结果
  • asked a question related to ANSYS
Question
7 answers
How it is possible to model Dynamic Eccentricity in Ansys/Maxwell software?
I can model the Static Eccentricity in Maxwell by changing the center of rotation from rotor center or vice versa, but I couldn't change it as a function of time, speed or position to model dynamic eccentricity in transient analysis.
Anybody could help me to model dynamic eccentricity?
Thanks in advance. 
Relevant answer
Answer
Dear Hamid Rafiei,
I used both methods to generate the eccentricity fault but still, simulation is showing error. I have attached the picture of the error and setting value using Eccentricity wizard.
can you please help with this [email protected]
Thank you
  • asked a question related to ANSYS
Question
3 answers
I'm exploring ANSYS's CutCell mesh method, which I think is similar to OpenFOAM's Snappyhexmesh, but with less optimization. It seems to generate good quality hex cells around complex geometry, but when I try to generate inflation, it starts creating a stair stepped mesh, and cells with poor orthogonal quality. Is there a way I can possibly improve this?
Also, is CutCell a viable mesh method?
Relevant answer
Answer
Hello,
It would help if you posted images of your mesh as well as where the poor quality cells are located so we can advise you best.
  • asked a question related to ANSYS
Question
2 answers
Fluent can also handle heat transfer with fluid flow analysis and it accounts for all modes of heat transfer. Now my question is then why we need steady state thermal or transient thermal analysis standalone system? What are pros and cons of steady state thermal in comparison ansys fluent heat transfer analysis? And most importantly when to use which one?
Relevant answer
Answer
Steady state and transient thermal analysis can be both done with CFD programs and heat transfer analysis programs. Transient analysis just means that you model something that varies in time (like heating up an object from initial temperature to a higher temperature). Steady state analysis seeks the equilibrium state reached after sufficiently long time (when boundary conditions are constant).
The standalone heat transfer programs are usually based on heat transfer correlations combined with analytical and numerical solutions. The convective heat transfer rate, for example, is calculated from known correlations, and thus the convective heat transfer coefficient is obtained very fast (and it is often quite accurate because the correlations are based on experimental data).
In CFD, you solve the convective heat transfer and fluid flow from full partial differential equations (which takes a lot of time and computer resources). The results might not always be accurate, because the turbulence models etc. might cause significant errors. From CFD, you also get a lot of results which you might not need if the heat transfer rate is everything you are seeking. On the other hand, with CFD you can model complicated cases where not heat transfer correlations are available.
Standalone heat transfer programs:
Pros: Fast to calculate (you can do optimization, sensitivity studies etc. easily). Might be more accurate than CFD.
Cons: Might be more inaccurate than CFD if no accurate heat transfer correlations are available for your case. You get less information than from CFD.
CFD:
Pros: You can analyze any geometry and case you need. You get a lot of data (turbulence, temperature, velocity fields in the whole simulation domain).
Cons: Slow to calculate, not so well suited for fast engineering dimensioning of devices (more suitable for advanced R&D). Might be more inaccurate.
  • asked a question related to ANSYS
Question
5 answers
Hello, I went through the Fluent Theory Guide and other Ansys learning resources, however I couldn't find the answers to the following issues.
Let's discuss the problem on the example of a general steady RANS k-omega case.
No slip Wall
U is set to zero, k is set to zero, omega is given by a specific equation.
1. What about pressure? Does Fluent use the zeroGradient condition for pressure on a wall? It's done by default in OpenFOAM.
2. NS momentum equations are 2nd order in space, so the boundary conditions should involve the normal derivative (e.g. dUn/dn=0), if I am not mistaken ?
3. Consequently, the turbulence transport equations are 2nd order in space as well, so should their respective derivatives be specified on a wall?
Velocity Inlet
U, k and omega are specified.
4. What about pressure? zeroGradient?
5. Refering to question 2,3 - should a Neumann BC be specified for U, k, omega?
Pressure outlet
Fluent Theory guide says that all variables (apart from pressure) are extrapolated from the interior. However, that does not sound right. Imagine a highly diffusive system, wherein turbulence (or any other scalar) is diffused upstream, faster than the downstream convection. In such a case, turbulence properties at the outlet would affect the solution in the domain.
6. As a consequence, what BC are imposed for U, k, omega? Mentzer suggests "intervals" which freestream turbulence properties should be taken from. https://turbmodels.larc.nasa.gov/sst.html
Symmetry
Fluent specifies zero convective/diffusive flux across the symmetry plane.
7. We should specify a value of k and omega at the symmetry anyway... right? It has to be done in OpenFOAM...
Thank you very much for your time and effort, feel free to make a comment on that.
Relevant answer
Answer
The boundary conditions depend on the case by case basis. It also depends on whether you are doing for incompressible flows or compressible.
Suppose you are working with incompressible flows and you have no idea about the initial pressure condition in that case you can opt for velocity inlets. In the same way if you don't have any idea about the velocity at inlet then opt for pressure inlets or mass flow inlet. If you use pressure inlet then always try to provide pressure outlet condition at the outlet. The distance between the inlet and the outlet should be enough to monitor the development of the flow. If the flow is not developed then the boundary conditions will not work for you so the geometry is also important to be understood. In such cases where you assume the the distance between inlet and outlet is very large but you provide a definite small value then try using Zero gradient boundary condition at the outlet to let the system extrapolate values from the region inside the flow domain.
  • asked a question related to ANSYS
Question
5 answers
I am a mechanical engineering student. I need a project on design using solidworks and analysis using anysis. Please share some basic solidworks and ansys project with me. I will try to do. Thank you.
Relevant answer
Answer
Move to simcafe a simulation platform by cornell university
  • asked a question related to ANSYS
Question
5 answers
I have written UDF in C, using fluent macro, “DEFINE_ADJUST”, for internal steam reforming (file attached). Reforming reactions are supposed to take place inside porous anode electrode of Fuel Cell. Pre-reformed fuel mixture is used which consist of (CH4, H2, H2O, CO, CO2) species. 6 source terms are generated (5 from species, 1 from heat sink, as steam reforming is an endothermic reaction). These source terms are hooked in "Cell Zone Conditions" of fluent. UDMI, memories in Fluent are also allocated to store data for above terms (see code file). Initialization and msr_adj are also hooked, segregated solver is used. Energy, species models are tern on.
After doing all these things and running simulation, reactions are not taking place; there is no change in concentration of species at inlet and outlet. Can someone take a look on UDF and suggest me what i am doing wrong? Heat is being provided outside the porous anode to facilitate the endothermic reaction.
In the next step I shall include electrochemical reactions in this UDF taking place at the surface of anode, which are exothermic. Reforming reaction reactions will use this heat.
Relevant answer
Answer
The error lies in this assumption: "Partial Pressure is equal to mole fraction when operating pressure is 1 atm". That is only true, if you disregard the units. However, in order to fulfil the units of the equations you take from Haberman and Young, you really need to be careful with the units:
The partial pressure of each component i calculates from the molar fraction and the pressure, which you assume to be the atmospheric pressure:
Xi = xi p(atm) = xi * 101325 (Pa)
Neglecting this leads to too low reaction rates. Thus, nearly no reaction occurs in your simulation.
  • asked a question related to ANSYS
Question
7 answers
Hi, I wanna ask for opinions/suggestions to reduce the percentage error between experimental and simulation results in the ANSYS workbench ( static structural).
First, let me explain my research.
I have cubic lattice structure samples (60mm x 60 mm x 60 mm) made from ABS thermoplastic material using FDM additive manufacturing. These samples were compressed using INSTRON 5585 universal compression test machine. The data from the test were analyzed to get the stiffness, young modulus, yield stress, etc. However, the results from simulation using ANSYS static structural were nowhere near the experimental results. For example, to get the stiffness, I divided the exerted force to the deformation and I get +82% error (simulation >> experimental). for young modulus, I divided the equivalent stress to strain and get -234% error (simulation >> experimental). I suspect these as the factors for the error
1. The samples made from FDM AM have too many manufacturing defects (interlayer failure+ porosity), yet to try using other AM techniques.
2. During the experiment, the area used was 60 mm x 60 mm as I cannot specify exactly the contact area (much less contact area) for the lattice to the bottom platen as the machine only asked me to put in the width and length of the sample. where probably (I'm not sure) the area used in the calculation in ANSYS is the actual contact area to bottom platen.
3. The structure is simply too complex.
I've tried using actual density and young modulus I get from experimental in engineering data and use force distribution plate to the top and bottom of the samples in ANSYS environment but not much changes.
also for case #1 is there any way I can render the geometry in ANSYS to have layers and voids as in actual samples?
Relevant answer
Answer
It is not quite clear to me what you want to do. Are you interested in the properties of the beams in your spatial frame, or are you seeking the properties of a homogenized continuum model? In the latter case, I can highly recommend the nice theory of cellular solids by Lorna J. Gibson, which she started in her Phd thesis supervised by Prof. Ashby. It is simple and gives good results and insights. You may find it in one of their books: Gibson, L.J., Ashby, M.F. (1997) Cellular Solids: Structure and Properties. 2nd ed., Cambridge University Press. https://doi.org/10.1017/CBO9781139878326
  • asked a question related to ANSYS
Question
1 answer
When I heat the structure and run the analysis, the deformation by temperature occurs, and we want to re-run the modal analysis on the deformation results.
It takes a long time to enter boundary conditions at once and run simulations.
Currently, ET is using 227.
If there's a way to solve it by using commands, could I know how to use?
Relevant answer
Answer
Taeho Kim Can you share the corresponding .cdb file?
  • asked a question related to ANSYS
Question
2 answers
I am modelling an impactor hitting a plate in ANSYS in Explicit Dynamics. I want to simulate multiple impact rather than one initital condition because whenever I try use Load Steps, it does not work well like the Load Step usage with Structural Static.
Thanks,
Relevant answer
Answer
This was on top of my head when I had to think about a way but, how do I perform an external code in ANSYS ?
Thanks in advance,
  • asked a question related to ANSYS
Question
2 answers
Hello, I use ANSYS explicit dynamics to simulate something and after running the simulation, I get this error message. How can we solve it?
Thank you!
Relevant answer
Answer
Unfortunately this is not the issue. The software is not limited and the issue I think originates from the folder that has the results. The solution is done but the results are not loaded. This never happens when I use any ANSYS mechanical or thermal simulation. Only explicit dynamics!
Thanks
  • asked a question related to ANSYS
Question
5 answers
Please suggest me how to change colour manually of imported bodies face in ANSYS DM. As option is their in View-Graphic Option- Face colouring-By named selection. But in this, while selecting named selection automatic default ansys colour were assigned. I want to assign manual colour for different bodies.
Please give suggestion
Thanks 
Relevant answer
Answer
Please look into the attachment
  • asked a question related to ANSYS
Question
9 answers
Does anybody know how you read datafiles from ANSYS Fluent for postprocessing data yourself?
Relevant answer
Answer
Ok!
  • asked a question related to ANSYS
Question
2 answers
Hye all, hope all of you doing fine today.
In my case for viscosity that dependent on temperature case, supposedly I need to tick the energy equation and laminar-viscous heating, unfortunately, the simulation will be faced with an error. But when I untick the viscous heating the system can be run and get the simulation result. As per attachment location for energy and laminar-viscous in ANSYS FLUENT, my UDF for viscosity dependent temperature case and error that appears when i tick the viscous heating.Thanks..any idea guys?
Relevant answer
Answer
do you have a temperature differences in your case, if you do not select the viscous heating? Your µ-T equation from the UDF changes the viscosity very strongly, around two orders of magnitude for a100K range, this will destabilize the iterative solvers of the CFD software. This µ-T equation seems to be a very rough guess at least over a broad temperature range, therefore you should limit it to a temperature range where it is valid for the assumed fluid.
Furthermore, you can try smaller under relaxation factors for the energy terms or artificially limiting the temperature to stabilize the solver.
Best regards
Christian
  • asked a question related to ANSYS
Question
2 answers
Hello everyone,
I am trying to do a static structural simulation in Ansys workbench. I have tried applying the bolt pretension condition but the solution does not converge.
Bolt pretension condition:
Part2 with external threads is connected to Part1 with internal threads (tightening torque-25Nm). I have applied the bolt pretension condition to the Part2 outer surface and load 20kN.
Please find the attached image.
Do i need to select the entire Part2 or just the surface in contact with Part1.?
How do i apply the bolt pretension condition..?
Thanks in advance.
Regards,
Vamshi
Relevant answer
Answer
Thanks for the answer Norie Allafi Akeel .
I have applied all the stated boundary conditions on the 3D model, just for understanding i have shown here the crossection.
  • asked a question related to ANSYS
Question
3 answers
Fatigue analysis on ANSYS Mechanical APDL
Relevant answer
Answer
You have to use Ansys workbench module to calculate design fatigue life analysis, It accumulates the damage from repeated loading to predicted the life of component.
  • asked a question related to ANSYS
Question
3 answers
In a constant volume chamber, we did 6 hole nozzle injector to simulate gas (methane) injection simulation. As part of the inlet boundary condition, we used velocity inlet boundary condition (i.e. 25m/s) for all the nozzles.
The results obtained are so confusing
1. The mass flow rate of each nozzle is different from the other.
2. With the increase in injection velocity, the simulation fails stating "Recycling requested by state variable update" and fails finally saying timestep driven is too small.
Why this phenomenon occurs.
The constant volume chamber is closed from every side, and nitrogen is filled in the chamber.
Relevant answer
Answer
If there was a heat transfer in your computation domain, maybe the density of the fluid in each of the nozzles were different. So, the mass flow rates were not the same...
  • asked a question related to ANSYS
Question
1 answer
During contact making procedure, I need to select multiple lines (say 100 lines) at a time. How can I select those lines through command in ansys apdl?
Relevant answer
Answer
Are they associated with any volume or area? You can try vsla/lsla to select lines from that area/volume. If you know the location try lsel command with loc. You need to provide more information to get specific guideline/information. Happy Researching.
  • asked a question related to ANSYS
Question
3 answers
Hi ,  My name is Ioannis Saramantas. I am a PhD candidate in the Department of Mechanical Engineering and Aeronautics in the University of Patras, Greece. I want to perform multiple simulations with varying composite fabric thickness as a parameter and at each repeat I want ANSYS to store and export  Frequency Response Tabular Data on various locations (nodes)  in the structure with Harmonic Response Analysis  and also tabular data from Transient Structural. Then to import them on Matlab for further analysis. Is this extension (V2.1 ANSYS Extension) what I need in my case? May you help me because I have spent many hours searching for a solution.
Best
Relevant answer
Answer
u just need to perform a *do loop including the marge of your parametres. then with use of *CFOPEN you can open a txt or CSV file and store your data accordingly.
the following code can help you get the idea
/POST1
*CFOPEN,strcat(chrval(iter),'Results'),txt,' '
*DO,i,1,Freqrang
SET,next
*get,Disp,NODE,Node_Fr,U,Z,Displacement
*VWRITE,Disp
%0.0f
*ENDDO
*cfclos
  • asked a question related to ANSYS
Question
4 answers
I am familiar with the GUI in Ansys APDL , but I don't know how code in ANSYS APDL I have been trying from many days but I don't know how to the parabolic loading for the above problem?
Relevant answer
Answer
I suggest you read this book (ANSYS Mechanical APDL for Finite Element Analysis) it explains very well how to use ANSYS APDL GUI and codes.
  • asked a question related to ANSYS
Question
6 answers
I'm relatively new to Fluent, and I'm performing a 2D analysis of a flow past a circular cylinder as a part of my project. The cylinder is 6 mm in diameter and the inlet velocity of 20 m/s, making the Reynold's number 7638. The drag coefficient value is around 1.97, which agrees with literature, while the coefficient of pressure value is ridiculously high. I've used a tri mesh, with 50 layers of inflation at a growth rate of 1.2. The first element size was calculated to be around 1e-5 for a y+ of 0.8, to capture boundary layer effects. This is a steady state analysis using the RANS k-omega SST model, but regardless, I don't think the value should be this high. The Cp vs length plot shows values of 500, which is much too high. I also plotted cp vs theta upto 180° (since fluent plots against length), and have attached it herewith. The nature of the graph appears okay I think, but can anyone please help me with why the cp values are so high?
I've attached a paper I'm referring to, for the cp vs theta values.
Relevant answer
Answer
If you use a incompressible solver, then a velocity U0 may be specified on the inlet while a pressure-outlet P1 may be used for the outlet. Thus, a value equals to the P1 could be used as a reference pressure. If you have modified "operating pressure" ( In view of the fact that "gauge pressure was zero" in your reply ) in the "Operating Conditions" dialog box, then the operating pressure should be set to a meaningful large value in order to avoid round-off errors.
  • asked a question related to ANSYS
Question
3 answers
I need to measure the water depth in the cylinder ( the picture attach) that mixes with air in Ansys CFX, and I don't find an excellent expression to do that.
Relevant answer
Answer
Hamidreza Razavi But from the provided image this does not look like very much like a flow with a clearly defined free surface? I wonder what causes in your application this rather diffuse mixing of the gaseous and the liquid phase - in particular the remaining liquid phase volume fraction above the green area? Are you sure, that you have a sufficiently converged solution here? Even visually I would do rather hard to determine a location of a "free surface".
Regards,
Dr. Th. Frank.
  • asked a question related to ANSYS
Question
4 answers
I'm trying to determine the lift and drag coefficient of airfoil DAE-11 for laminar flow using Ansys Fluent laminar model.
RE = 260941.0492
Number of cells = 495700
Maximum mesh skewness = 0.84481
Minimum orthogonal quality = 0.11398
Maximum aspect ratio = 163.72
Wind speed = 4.075 m/s
I had tried playing around with SIMPLE, SIMPLEC and Coupled as well as skewness correction, courant number and relaxation factors. Lift coefficient, drag coefficient and residuals for 10AoA are included in the attachment. Both coefficients never stop fluctuating. Am I doing something wrong?
It might be worth mentioning that for 0-3 AoA, both lift and drag coefficients managed to settle down around 600-700 iterations with continuity residual of about 1e-3.
Relevant answer
Answer
Hi Chi hung Chong
I think Shijie Qin's explanation probably can solve your problem of convergence. If you get any improvement kindly let me know.