Recent Discussions — Forum

Manipulating constraints within simulation

Sarvesh — Mon, 25 May 2026 09:48:31 +0000

Hello Expert community,
I need one help in manipulating constraints within simulation time steps. Is it possible to perform this operation with Calculix?

Openfoam Pressure Import ASCII BARAM v26.1

stoplic — Tue, 31 Mar 2026 21:02:16 +0000

Hi there i have a question about importing openfoam results as pressure for further stress Simulation.
I have use it in Prepomax i for example the pressure of a traffic sign in a Orkan was solved in BARAM v 26.1 des Solution File was written in ASCII format not binary the import in Prepomax of the Foam file was no problem. Is the same Possible in Mecway? Thanks for every Answer better a approximate solution the no solution love ya

Managing solid geometry

Mishal — Tue, 26 May 2026 06:41:49 +0000

Hi Guys

With regard to the use of surface geometry it is pretty easy to modify thicknesses to perform iterations on designs.
However, when it comes to solid geometry, how are you guys managing the models?

Say there is a plate and the thickness needs to be increased, since Mecway does not link to a modelling interface directly (like Discovery from Ansys) you need to modify this on your CAD model and then basically rebuild a new model. Have I lost the plot or is there an easier way to manage this?

Simulation of Planar Magnetic membranes; tweeter and midrange.

solhaga — Wed, 13 May 2026 14:53:59 +0000

For the full context, please look in this thread at diyaudio.com.

I'm new to Mecway, so please bear with me if I'm using the wrong vocabulary or asking very simple questions.
I'm not all new to FEA; I've been using FEMM4.2, simulating magnetics for loudspeakers, for many years.

A planar magnetic usually has the following components:
Steel plates,
Magnets,
Membrane,
Electric conductors.

The electric conductors are usually very thin aluminum foil bonded to the membrane.
The membrane could be PET, PEN and so on and is also very thin.

I want to use Mecmay to simulate eigenmodes of the membrane and then the modes from applying force from the aluminum foil so that I can come up with countermeasures, as these modes most often introduce harmonic distortion.

My first problem is:
In the tweeter case I have a 12µm PEN membrane in a retainer. The free part of the membrane is 75mm in diameter, it is glued to the retainer while being tensioned.

I want to find the bare membrane's eigenmodes.

I have managed to mesh the design, and I have a named selection for the perimeter.

But I don't know what Loads or Constraints I should apply to the perimeter.

Gmsh import tracking as Shell (M3) instead of 3D Solid in Mecway

marcosprojetos — Sun, 17 May 2026 17:06:00 +0000

Hello everyone,

I am having an issue when importing a 3D solid skid model from Gmsh into Mecway. Even though my model is a solid, Mecway treats the mesh as a shell/membrane and keeps asking for a thickness.

As shown in my screenshots:
1. In Gmsh, I open my STEP file, generate the mesh (1D, 2D, and 3D), and then save it normally using "Save Mesh" (Ctrl + Shift + S).
2. When I open this mesh file in Mecway, all 174,278 elements go into a single "Default" component.
3. Mecway flags it with a "What's wrong?" error because the geometric property is set to "Shell / membrane" instead of "Solid".

If I check the element properties in Mecway, the shape is listed as "M3" (triangles). This means it is only reading the surface/skin as shells, instead of actual 3D solid volume elements (like tetrahedra).

What am I missing in Gmsh during the mesh generation or setup so that the mesh is saved as a true 3D solid volume that Mecway can recognize right away without asking for thickness?

Thank you!

surcharge on retaining wall

Mishal — Wed, 13 May 2026 11:49:05 +0000

Hi guys

Please to the attached image. The surcharge load can be calculate using Boussinesq's method, however the theory does not apply due to the proximity of the lo to the wall.

Is it possible to model the soil as an Isotropic material with appropriate mechanical properties to simulate the soil profile?

Thanks in advance

How to connect/weld parallel Beam Elements (unifilar model) without shared nodes?

marcosprojetos — Mon, 11 May 2026 18:32:06 +0000

Hello everyone,

I am working on a structural model in Mecway using Beam Elements (wireframe model). I have a specific question regarding how to simulate a welded connection between components that are physically separated in the geometry.

My Scenario:
I have a 'sandwich' assembly consisting of:

A top square hollow section (tube).

A flat bar in the middle.

A bottom square hollow section (tube).

In the real world, the flat bar is welded to the outer faces of both the top and bottom tubes. However, since I am using line elements, I don't have physical surfaces to select and use the Contact (Bonded) command. When I run the solver, the three elements act independently and the load is not transferred.

My Question:
What is the best 'standard procedure' to 'glue' or 'weld' these parallel lines together so they act as a single rigid unit?

Should I use Rigid Constraints (RBE2) to link the corresponding nodes vertically?

Is there a way to create an automatic link or coupling between these parallel lines?

Or is it better to create manual 'connector' beam elements with very high stiffness (high Young's Modulus) to simulate the weld?

I am looking for a reliable way to ensure the 'sandwich' works together without having to model the entire structure as solids.

Any advice or 'recipe' on how to set this up correctly would be greatly appreciated.

Thank you!

Weird behavior with cyclic symmetry, plasticity and contact

LucasG — Sat, 02 May 2026 18:53:17 +0000

Hello!

I've been trying to run a 1/12th model of a bolt tightening + pressure loading simulation of an API flange.

I've previously managed to run it without symmetry and the run times weren't satisfactory plus I was running into non-convergence so I decided to switch to the 1/12th model to troubleshoot faster.

I've since run into the weird phenomena below, and haven't found yet what could be causing it. I was wondering if anyone could shed some light in how to properly set up this model and/or what I might be doing wrong?

1) Whenever I set the output to anything more than 12 segments, I get a MecWay crash once the very first increment is done.

2) I get this weird stress concentration on the ring gasket and its channel at the symmetry faces. See picture 1. If I run with sliding support it seems to behave properly however I'm not sure if this is the proper boundary condition choice.

I've tried switching solvers, refining and coarsening the mesh in the circumferencial direction, unstructured mesh on the blind and weld neck flanges, changing contact settings, removing plasticity, different boundary conditions... Nothing seems to have an effect.

Thanks in advance!

dynamic response on steel frame

sofien_73 — Tue, 28 Apr 2026 07:09:00 +0000

Hi everyone,
I have designed a steel frame using spectrum analysis for seismic hazard.
I have made the same analysis using ROBOT.

On the classic ULS (wind, snow, DL) I have very close results between my MECWAY model and ROBOT.
But for dynamic design beam forces increase by twice (for example bending moment on top of the columns Mw (MECWAY = 136748Nm // ROBOT My = 56815Nm)

Spend a lot of time to understand what's going on here my results:

->reactions are the same
->mode shapes and frequency are the same

I wonder if on MECWAY dynamic dynamic response there's something that I had misunderstood.

I'm not sure that rotationnal mass inertia which can be controled on an accurate solver in ROBOT make so much impact on MECWAY model.

Hope there's something easy that is out of my sight.

Here's the model.

Best regards.
Sofien

Step-by-step help needed: Bolt Pre-tension on split vs. solid geometry (CalculiX)

Marcos — Fri, 27 Mar 2026 01:33:04 +0000

Step-by-step help needed: Bolt Pre-tension on split vs. solid geometry (CalculiX)
Body:
Hello,

I am struggling to get a reliable bolt pre-tensioning workflow in Mecway using the CalculiX solver. I have tried both a single-part bolt and a bolt split into two halves (modeled in Alibre Design).

Could someone provide a clear step-by-step on how to correctly apply the pre-tension? Here is my current situation:

Face Selection Issue: I cannot seem to apply the "Pre-tension section" to the internal cross-section face of the bolt. The option is often greyed out or gives a "Not available for this selection type" error.

External Surface Workaround: I only managed to activate the command by selecting the external cylindrical surface of the bolt. This creates the green vector, but I am unsure if this is the correct physical representation for a structural simulation.

Split Bolt Setup: When using a split bolt, should I use a "Bonded" contact between the two halves in addition to the pre-tension? Or does the pre-tension tool handle the connection automatically?

What I need is a definitive "best practice" guide:

Step 1: How to prepare the geometry (Solid vs. Split).

Step 2: How to ensure the internal face is "seen" by the mesh as a valid pre-tension section.

Step 3: Correct settings in the Pre-tension dialog (Force vs. Length).

I've attached screenshots of my current model and the convergence monitor. Any help to stop this "trial and error" would be greatly appreciated.

Thank you,

Constraining circumferentially with polar coordinates

yankee — Tue, 21 Apr 2026 03:48:45 +0000

Hello, I want to constrain an axial turbomachine about the engine axis as well as circumferentially, and leave it free radially. However, the only place I see I can constrain a face by an axis is in the "displacement" constraint. However, this is only in cartesian coordinates, and this use case needs polar coordinates. Does anyone have a work around for this?

Thanks!

Quasi static convergence

kuhl — Fri, 17 Apr 2026 15:21:26 +0000

Hi all,
I'm having trouble getting a model to convergence with nonlinear static analysis and quasi static activated.
It solves with no problem as a "nonlinear static" analysis if "quasi static" is deactivated and also as a "nonlinear dynamic" analysis.

Convergence fails right away at the beginning.
There are only tie contacts in the model.
Is it typical for quasi static to converge more difficult? Any hints what might help?
Thanks!

Spring modelling

mike — Wed, 22 Apr 2026 20:23:55 +0000

Is it possible to model something like this where the vector pulling on two springs is straight up so the springs are being pulled at an angle to their axis. I know this configuration can give a reaction force where it plateaus out at a constant force for a bit. I have an idea for something similar in a mechanism I'm designing.Thanks!!
PS Red lines are the springs

Contact stiffness approximation

Mishal — Fri, 17 Apr 2026 08:58:03 +0000

Hi Guys

I come from a Strand7 background which uses a very different formulation for contact compared to CCX. What is the easiest way to estimate the contact stiffness in a model?

Something like K = E/H where H would possibly the average length of an element...

S4R elements

Fatmac — Wed, 22 Apr 2026 15:18:45 +0000

I have been working thru a few shell examples from this document https://hub.hku.hk/bitstream/10722/54269/2/92945.pdf to get a better feel for the shell elements used in Calucix - particularly with non-linear analysis. I have set up a solid model as a control and have been playing around with different shell elements. With S4 elements the solution looks reasonable compared to the abaqus results presented in the paper

But, from what I understand, S4R elements were used in the study, . When I try to use S4R the deflections are significantly less -perhaps I am not setting it up correctly?
any ideas

Brain Cramp Displaying/getting Force vs displacement

mike — Fri, 17 Apr 2026 05:51:50 +0000

Hi! Doing a quasistatic analysis in Calculix nonlinear static 3d. For some reason I'm not getting the external force value to show up as a sum in the table. Even when I create a sum based upon the displacement face (or restraint face) It's not showing up as an option when building the table. I see every node in that face for each time, not the sum. I could've sworn once upon a time I did force/displacement curve instead of force/time in the graph at the bottom of the UI. Thanks for you help!

Modal Analysis of Axial Flow Rotors / Fans

yankee — Sun, 19 Apr 2026 21:59:19 +0000

Hello!

Does anyone have any experience with the constraints / boundary conditions involved when performing modal analysis on axial compressor / turbine rotors? I've searched through many different sources and find contradicting and varying practices. Some constrain the root, some constrain the shaft ID, some use cyclic symmetry with fixed constraints, and some use cyclic symmetry WITHOUT fixed constraints.

The geometry I am using is an integrally bladed blisk, so there is no blade root. As of right now I think the best practice is to use cyclic symmetry with a fixed bore ID, but even then someone online said that no fixed constraints should be used since the whole system can be flexible.

I have tried many different ways and combinations but the results vary so much that I am afraid to just pick one and go with it. Does anyone have any personal experience with this?

Thanks!

Mecway and ABAQUS Compared to ASME PTB-3

Sergio — Fri, 01 Nov 2019 19:00:59 +0000

Hi, I'm working on some under pressure parts, and in order to validate the results, took as reference this problem found in the PVEng site:

https://pveng.com/wp-content/uploads/2016/06/PVEfea-9128-1.0-Abacus.pdf

First results looks very close to the references values (probably the difference is due to different geometry in the drawing than in the model used in Abaqus report, see the plane surface between SCL#3 and 4).

@Victor , is possible to compute the "primary membrane stress + primary bending stress + second equivalent stress" (Pl+Pb+Q) with the stress linearization results???

Regards

Free in translation

Mishal — Mon, 13 Apr 2026 12:53:08 +0000

Hi Guys

I am currently using the internal solver. The pinned restraint allows for fixity in translation in 3 directions however I just need to fix one of them. How can this be performed?

Using Mystran inside Mecway

Fatmac — Wed, 08 Apr 2026 20:40:09 +0000

I have been keen to run a little study on shells vs solids and was particularly interested to see how mystran performed. I set up a simple test with 100x100 mm 1mm thick ,100 GPa material which was simply supported. in both shells and solid. ( I realise my solid supports and perhaps not exactly as the shell supports but close enough for this quick look i think.) I imagine the results will not surprise anyone (although I was impressed how few elements Mecway and Mystran shells required to get close to the theoretical value)

What was a little more surprising to me was how ( this setup) how poorly the mystran solid elements performed. I do wonder if I am missing something in the set up as I could also see no stress or stain values for the mystran output

Line Elements for Thermal Movements / Stress

Sandrailstudent — Wed, 25 Mar 2026 23:55:27 +0000

I am trying to use Mecway in place of a pipe stress program in order to find the reaction forces on some pipe supports. The temperatures modeled a the nodes "should" produce thermal displacements, but for some reason they don't. With solids and meshed models I have been able to get results before, but this seems to be a new challenge changing to line elements.

Are there things that i can do that would allow the program to solve for thermal movements? It would be way easier on my side to do this with line elements than to build it in shells and locate everything everything.

Thanks in advance,

Chris

Damage Initiation

Fatmac — Fri, 03 Apr 2026 13:00:31 +0000

I have been experimenting a little with damage initiation now its included in 2.23, I have followed a simple tensile test i noticed someone else was experimenting with. I have tried to add a custom card but I am unsure if I have done this correctly It appears to have done something to the analysis but I'm not sure exactly what. I think once an element exceeds yield it gives up fighting. If I can understand better what is occurring here I think this may be useful in predicting failure point and certainly mechanisms in some parts. By adding this in a custom card I wonder if it is place in the correct place in the .inp file in the calculation? The solution is a little odd in that once any damage starts there is zero stress in the rest of the part and no elastic strain is recorded. (with the damage initiation removed there is some plastic deformation). Also I experimented with a large range of values for the Rice Tracey number and it appears to have no affect on the results.
So my question really is have I applied this criteria
. I did try inserting it in the CXX custom material input but had no luck with that -mu guess is this is the likely to be the correct way to do it but I need some help as to how.
As an aside I also wanted to know why there is a difference between summing up external forces over faces and nodes -in this analysis i can see the different solutions as below
the one based over the faces in this case looks like it gives a more likely answer

Element Stress with CCX

kuhl — Wed, 01 Apr 2026 08:50:14 +0000

Hi all,

sometimes I have to model adhesive layers as solid. When possible, I try to model matching meshes for the parts that have to be bonded and extrude the adhesive layer. Then I merge nodes so the adhesive layer is connected.
For the internal solver that works fine, as I can choose between node values and element values in the results.
If I have to use CCX, I don't get that choice and only node values are available which means that the stress shown at the interface between the adhesive and the bonded parts is way off due to its much lower elastic modulus.
Currently, my workaround is to use contact to connect the adhesive wich can be annoying sometimes.

Internal solver (element values), top: connected by contact, bottom: merged meshes
pink: above range

CCX (node values), top: connected by contact, bottom: merged meshes
pink: above range, grey: below range

Is there a way to get element values with CCX solver or some other way to evaluate the stress in the adhesive?

Material Library Available or Tips to Build?

bumpsteer — Sat, 28 Mar 2026 01:09:10 +0000

Hi all, apologies if this has been hashed out before, but the only thread I seem to be able to find is this one from 9 years ago and I am perhaps optimistically hoping there may be some alternatives for someone who is very much not talented at writing scripts.

Is there any decent (even if limited) material library I can download to point Mecway to in order to get me started?
Alternatively, any pointers/other threads that can help with a strategy for efficiently building one? My current strategy is simply filling out each material entry to my local library as I come across new materials needed for analysis, and doing so as completely as possible in the event that I need to use this material for a different kind of analysis in the future.

Thanks in advance (even if the answer is to tell me I'm simply being lazy!) and just want to say that I'm glad Mecway exits, it's really cool that between this and Alibre (which has its own challenges), I have a perpetually licensed and affordable workflow for designing and analyzing mechanical assemblies independently.

Mecway 33

Victor — Fri, 20 Mar 2026 07:26:33 +0000

Mecway 33 is now available at the link below and includes the Spanish language manual translated by Germán Bresciano.

https://mecway.com/download/mecway330.msi

This is currently a release candidate so it has a higher risk of new bugs. If no serious bugs are found, it will be promoted to a stable release, otherwise it will be superseded by version 34.

Changes

General
Saved views can include view options like Show element surfaces and Deformed view, and component visibility state.
Vertical scroll bar for laminate input box.
Reduced memory use for element values in solutions.
Shell offset in Element properties is deprecated in favour of Element offset in Loads & Constraints.
Contact item in outline tree shows type and stiffness.
Face selections that are linked to geometry surfaces show the number of surfaces in the outline tree like

Gmsh
Setting for Mesh.Algorithm (2D mesh algorithm). Default is now 2 (automatic) which often gives better element shapes than not specifying it.
No longer generates unused midface nodes for quadratic quadrilateral faces.
Can read 14-node pyramid from Gmsh. Leaves the 14th node unconnected.
Changed from the deprecated CharacteristicLength... to equivalent MeshSize...

Internal solver
Modal effective mass and modal effective mass fraction. Not available when MPCs, including rotated constraints, are present.

CalculiX
CCX version updated to 2.23.
Velocity initial conditions can have the magnitude be a function of position.
Incompatible hex8 is required for CCX solver.
Clearer error message for missing contact state on elastic contacts with time steps.
Doesn’t show "Unknown reason" or missing dependencies error message for stress when beam section forces are present or for stress in frequency analysis when stress stiffening is present.

OpenRadioss
Removed version option and recommended only stable release 20260120. This affects beam internal forces and moments in the solution which were defined differently by OpenRadioss before 2026.
C, T, L beam sections.
Error message for shell offset instead of silently ignoring it.
Velocity initial conditions and boundary conditions can have the magnitude be a function of position.

Mystran
Pinned support.
Constraint equation.
Solution includes von Mises by default.
Updated bundled solver to commit ae40b55 from 2026-02-16.

Bug fixes
Added missing GRID to modify bulk data entry name list for Mystran.
"Operation is not valid due to the current state of the object." after deleting certain rows from a table in a load.
Undo altered the names of saved views.
"Object reference not set to an instance of an object." with Pre-tension section applied to no elements in the internal solver.
Pressing the Stop button on an iterative static solve discarded the solution instead of retaining the last iteration.
Fatal error for laminates with more than the maximum allowed number of layers (40).

CCX version updated to 2.23 vs 2.22

Fatmac — Sun, 22 Mar 2026 10:03:44 +0000

I have seen some differences in the solution generated from the same model in Mecway when I use 2.23 and 2.22 ( specifically a non linear contact involving bolts and pretension). In some cases 2.22 converges easily and 2.23 requires a different analysis set up to converge whatso ever. Has this been reported else where and are there any potential reasons for this? which solution is likely to be more reliable? I have attached the file 2.22 solves with out the need for automatic time stepping but 2.23 does not - the maximum stress is also different. I can well believe my approach to this particular problem may be questionable but I'm surprised at the difference in the solutions.
Incidentailly is there a way to be able to use the PARDISO solver with 2.23 ?

Geommetry preparation capabilities in Mecway

JJJ — Sat, 21 Mar 2026 13:24:46 +0000

Hello,

I am new on the forum, recently I acquired a license, nice to meet this so active comunity. I have a step model imported, and I want to do some modifications (division of some surfaces, or to move some corners nodes, for example). Is it possible to do on Mecway, or I have to go to the CAD software and make changes there and export them?
On the other hand, I apreciate some recomendations for the next issues I want to take into account in my model (bolted connection modeled by surface elements):
1- Sloted holes. How can I define the behaviour of these holes properly? Is there a way to define a constraint between two nodes to simulate that type of behaviour?
2- I have some parts welded. I am thinking about avoid modeling the welds, and then get the internal forces in nodes and make verifications. How can I do this?
3- How I define the contact between surfaces? Shall I have to separate the same distance than the thickness of the plates?

Finally, I have read that Openradioss can perform Implicit analysis. How I can define this in Mecway?
Thank you very much.
JJJ

Extraction of section forces in solid model

JSC — Tue, 17 Mar 2026 16:50:47 +0000

Hi,
I am doing some nonlinear analysis of a steel structure with some intermittent welds ("stitch welds", also part of the model with either wedge15 or hex20). Apart from validating the whole structure I need to verify some critical welds preferably by Eurocode 1993-1-8.

To do this I need section forces which I can post-process in e.g. excel to get stresses (sigma.transv/tau.parallell etc).
After some trial and error on side examples I have found a resonably simple solution by extracting external forces (FX,FY & FZ) from pre-defined areas corresponding to the leg lengths and weld lengths of the interesting welds. For the extraction I used the [Sum]-tool (the coordinate system for the welds align with global x/y/z).

So here is my question; is this a reliable method or am I missing something?

Working with surface integrals and S.xx / Syx etc on the same areas seems to be far too uncertain given stress spikes and it also appears very mesh sensitive in my view.

Any comments or feedback are highly appreciated.
/Jan

CXX Contact

kuhl — Thu, 05 Mar 2026 17:22:45 +0000

Hi all,
I am having issues with CXX contacts (symmetric model of rod in a hole).
Contacts 3 and 3b (bonded, elastic) cause stress without any load on the model.

It gets worse with increasing contact stiffness (1st image: 2000 GPa/m, second image: 200000 GPa/m

What am I missing?

Need Help with Radial Displacement Plot

windys53 — Sun, 15 Mar 2026 23:16:53 +0000

I have a 3D static analysis results of a blade (see attached model file) and would like to plot radial displacement. Can anyone help me with this? Thanks in advance.