Stuck? 
support@mecway.com
support@mecway.com
Mecway
FEA
Victor
About
- Username
- Victor
- Joined
- Visits
- 4,098
- Last Active
- Roles
- Administrator
Comments
-
To be clear, this is only a problem if you're going to do mode superposition or otherwise using the mode participation factors from the CCX output files, not for general frequency analysis, is that right?
-
I'm not sure using the higher stress at material boundaries is the right way. While it might be practical and conservative, it wouldn't be obvious that it's doing that and there's ambiguity about how to order tensors. I'm not sure what you mean in …
-
Yes, since version 25, in part because you pointed out the need. Sorry it slipped by. The Y-rotation constraint is for the reference node (ROT node), but structure itself is free to rotate about the line of nodes because there's no way for a rigid …
-
You can use Node-surface coupling for this with either the internal or CCX solver, and small or large displacements. Here's an example. Note that the line axis (Y) rotation constraint is required when the nodes are collinear and it isn't actually co…
-
Just a thought, but perhaps it's possible to model the bolt in it's relaxed shorter state, then let the contact pull it to fit? You might have to write the contact cards by hand or disable the ADJUST parameter on *CONTACT PAIR. As with cooling, you …
-
Part of the difference between *TIE and unilateral may be the contact stiffness which is effectively infinite for *TIE and looks a bit low for elastic in your screenshot. I would compare bonded elastic to unilateral elastic to make it more apples-to…
-
You can add it through Solution -> Stress and strain -> strain.
-
I think it kind of does but the build from OpenRadioss don't have it enabled. In 2022, one of the maintainers said "It is not possible to provide the direct usage of /EIG functionality in OpenRadioss, yet." The only ARPACK alternative I know of is F…
-
@JohnM Amazing. Thanks. It was @Sergio who prompted me to do this. At first I thought it might be a less buggy alternative to CCX but this explicit dynamics thing is incredible. More integration coming in Mecway 27.
-
Not really. Here are some possibilities: Use line3 elements and take the force at the midside node. It's still not listed under Element values but isn't polluted by values from other elements sharing the node. Beware that line3 truss elements shoul…
-
I'm pretty sure this is a CCX bug so I've submitted it on Github here https://github.com/Dhondtguido/CalculiX/issues/97 Here's my minimum example
-
Oh, that's not right. It seems to be missing the external forces on one side of the shells. Here's a simplified model. I'm still working on isolating when it happens.
-
That's good. I still have trouble with those settings so if you do too, other things that help are: - Smooth the corners of the curve by adding more points near whatever stress/strain it stops at. - If the solution stops near final point (0.15, 470…
-
Two things: Z Displacement constraint on the common node to constraint rigid body rotation. Either turn off quasi-static or make the force time-dependent (250*t). Quasi-static with no time dependence often fails.
-
Great to hear you solved it. This would have been a confusing one.
-
Mecway 26 requires .Net Framework 4.8 so please install that. I'm not sure why the error message says 4.0. Mecway 23 used .Net Framework 4.5 so if it still doesn't work, maybe try that ( https://mecway.com/download/oldversions/mecway230.msi ) to se…
-
Here's a model I just put together. I hope that's helpful.
-
@LHartly, it's @Disla who's the big thousand-word photo poster. This might be my first :P
-
@LHartley only if there's no global buckling mode with a lower critical load. If you removed the guy wires, I imagine this truss/frame would begin to buckle globally before any individual member fails.
-
Copy/paste, sorry. A few people have asked for variables like that so hopefully in future.
-
I see these error messages start to look useless when they say something's not allowed but it still works. Maybe it should explain the reasons too. Nonetheless, I still wouldn't use *TIE on shells because you never know if it's quietly over-stiffeni…
-
@disla > I'm obtaining a different result each time I press the run button and only after 5-10 runs a credible result pup up which by the way only fits my expected result if I keep the second buckling factor. Would you be able to send me that …
-
You can usually use the elastic option instead of *TIE. It works on shells. *TIE kind of works sometimes but it's unreliable and I'm not sure what all the failure modes are. Nonlinear analysis not converging is usually because of unconstrained rig…
-
When I suggested node-surface contact, I meant just using that to make the surface rigid, not to connect it to anything - you can use one of the surface nodes or some other unused node as the reference node. If you really don't want to mesh the fla…
-
No, sorry. I'm not sure it would be safe to do that automatically since Mecway doesn't know how much of the contact area will actually be connected before solving. If you could use the internal solver, you might make point connections with line2 fi…
-
No. You have to use a mesh of the surface. But it can be a single solid element if it's rigid. You can make it rigid with node-surface coupling or use high Young's modulus.
-
It sounds like a poor quality mesh but such elements are supposed to be indicated with a red "X" visible in wireframe view. Do they show that? If not, could you please send me the file to investigate why they're not being detected?
-
In the DC current solution, you can use Solution -> Volume integral to integrate power density.
-
You can make these settings in Analysis settings: Analysis type: Buckling Modes: 3 or whatever Shift point: 1 seems to be OK. It should be lower than the lowest buckling factor but not too many orders of magnitude lower or the error increases. Bewa…
-
Mesh the plate and use contact with the CCX solver and Nonlinear Static 3D. If the plate is effectively rigid, you can use a very coarse mesh, like one huge element.
