When post processing my FEA results, the question comes up quite a bit on whether to look/use the corner or centroidal stress values. I understand the differences between the two types and have read over the years that large differences between the two data types indicates that further mesh refinement is required to get a more accurate view of the stress.

What I've never seen discussed anywhere is what is typically considered a "large difference" between the 2 that should make you consider refining the mesh. For example, a current linear static analysis i am running shows a roughly 45% increase changing from centroidal (31 ksi) to corner ( 45 ksi) looking at max prin stress.

Hi all, i am new to modeling, so apologies if i missed any essential information.

I’m implementing geometrically nonlinear static analysis for a large aircraft wing FEM model in a in-house tool and I’m running into a very strange, repeatable convergence issue.

The model is a composite wing structure, mostly quadrilateral shell elements, with RBE2/RBE3-type couplings and distributed kinematic constraints. Loads are applied through reference points along the wing.

I’m using conventional Newton-Raphson with load control.

the solver approaches a stage/load parameter of approximately: 0.00221323 Eventually the increments become essentially microscopic and the analysis makes no meaningful progress.

What makes this strange: The deformation at this point is extremely small, so I do not expect this to represent a buckling event. Artificial damping over several magnitudes also did nothing. path-following continuation can move around the region, but tends to follow a backwards/looping branch. Zero load converges perfectly. My current interpretation is therefore that the nonlinear tangent stiffness is approaching a near-null direction. What diagnostics would you use next?

Hi, I'm new to HyperMesh and I need to create a simple mesh for a plate and a ball.

In particular, I need to create a different mesh density on the plate, with a finer mesh in the center and a coarser mesh towards the edges.

How can I do this in HyperMesh? I haven't been able to find a good tutorial explaining this.

If you know of any tutorials or resources that could help, I'd really appreciate it. Thanks!

For engineers who have to compare many possible design variations, I'm curious how you actually handle it in industry.

For example, if you have hundreds or thousands of possible geometry/parameter combinations:

• How do you decide which designs are worth simulating?
• Do you actually run simulations for all of them, or use some kind of screening/optimization method?
• What tools do you use for this?
• What part of the process takes the most time?
• Is computational cost the main limitation, or is setting up/running/post-processing the simulations the bigger bottleneck?
• Do you use surrogate models, reduced-order models, optimization software, custom Python scripts, etc.?
• What happens when the design space becomes too large to explore practically?

I'm particularly interested in how this is handled in industry and what the biggest bottleneck is in practice.

Hi guys,

I am starting my journey in Code aster to do FEM of PCBs and electronic boxes. Is someone working in this direction? I offen get doubts regarding approach and functionality in solving problems.

I have been working with the tool gor now 3 months and previously worked with Ansys Icepak.

Thanks and regards!

hi everyone what was the most difficult type of analysis you performed, or one that you found challenging? Mine is harmonic acoustic.

Does anybody know any good course for Ansys? Am a complete beginner and want to hold a grip on this one by getting taught by someone good.

Hi everyone, I’m trying to understand how long-term thermal behavior is usually handled in COMSOL for rotating machines. For example, PMSM simulations are often performed over only a fraction of a second or a few electrical cycles, but if I want to study the temperature evolution over 1–2 minutes, how is this normally done? In my case, I have a rotating conducting plate heated by permanent magnets, and a fully coupled electromagnetic + thermal simulation becomes extremely heavy because the electromagnetic field has to be solved continuously during the rotation. What is the recommended approach for predicting the temperature after 1–2 minutes without simulating every single rotation over the entire period?

At work we are designing a spacer for a wall mount shroud. The shroud is attached to the structure by 4X bolts. The bolts go through the spacer holes and the back plate holes of the shroud (both holes are identical in size). The shroud is a two piece nylon split at the middle. When working on my checks I did check for bearing stress on the spacer holes but the senior stress lead told me to not having to check for it because its not in the load path. Can someone settle that debate?

I'm running simcenter 3D, and I have some items that could be simplified as a 1D beam element. The issue is that they are concentric multi-material assemblies. Are there any tools to capture this?

I'm a mechanical engineering student. Every stack-up I've seen has been done in an Excel sheet that one person built, nobody else fully trusts, and everyone copies anyway. So I built a browser tool for it.

You enter the chain of dimensions straight off the drawing. Asymmetric tolerances like +0.10/−0.00 included, and it runs worst-case, RSS and a Monte Carlo simulation side by side. It shows the resulting gap for each method, whether it clears your limits, and which single tolerance is actually driving the variance. Its completely free no signup or anything and nothing leaves your browser.

https://stackupcalc.com

I'd genuinely rather hear what's broken than what's good:

- Tolerance bands default to ±3σ. Is this the right default or should it be something else?

- Does the contributor ranking match how you'd actually attack a stack, or is that not how you think about it?

- What would stop you using this instead of your current sheet?

Some things I'm already aware of, so nobody has to point them out: it's 1D only, and it doesn't model bonus tolerance at MMC. I'm def curious whether that's a dealbreaker or a nice addition, it does change what I build next.

Happy to explain any of the maths if something looks off. If a number is wrong I want to know.

Hi guys, I am trying to run SOL400 job and I can see that analysis is struggling with convergence. How do I terminate the job while saving the results from the completed increments? Ctrl-c terminates the job but doesnt save the results. I also have NLOPRM OUTCTRL= INTERM, which outputs op2 file for each increment, but it creates for each increment separate op2 file, so for debugging its tedius since you have to load results from many separate files.

Is there some trick for this?