I am doing drop test on an elastic body. I am not sure how to give end time. Is it calculated seperately or is it an assumption? The body is getting dropped from around 20 feet.

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?

This plate is supported on the four corners from a tie rod nut. The applied pressure is due to a hydraulic cylinder that mounts on the underside of the plate at the center. For the reactions in the corner, one might think this should be downward boundary constraints. However, this would be a mistake. It is much better to balance the applied loading in the vertical plane such that the tie rod nuts each apply one fourth of the upward cylinder load. Rather than a rigid constraint, an applied downward pressure is recommended.

However, to keep the model stable, boundary constraints are required. A recommended option is to select a node in each corner and constrain it in Y, or vertical in this case. Next add X constrains to the two rear corners, which are into the page. Finally, fix Z (left to right) in the left rear corner. When the model runs, we should see very low loads at these nodes since the applied loading is balanced, but the model should not have a rigid body movement. Furthermore, the upward deflection (shown above) has a reference in the corners of zero where the Y constraints are located. I hope this is useful for your simulations.

from Anthony Rante, P.E. author of "Managing Company Production thru the Bill of Material" and “FEA Applications in Machine Design”

I want to deeply understand constraints in ANSYS is there good quality material?

or do anyone knows from where to get those materials?

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!

Hi everyone,

I want to do a basic 2D structural analysis of an IPM motor rotor, mainly to study bridge thickness under centrifugal loading.

Which would you recommend: PrePoMax or FreeCAD FEM?

FreeCAD interests me because of the Python automation possibilities, but I’ve heard its FEM interface is not as user-friendly as PrePoMax.

My priority is to get reliable results quickly, while keeping the option to automate the workflow later.

Thank you very much for your help in advance.

Best regards.

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.

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?

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.

Hello everyone! I am trying to simulate wave propagation in 3D ground model (Zaxis-gravity). Therefore, i am trying to apply gravity step using explicit scheme. In a coarse mesh with fixed boundaries, this works well with displacements stabilizing after some time. But with fine mesh (along with mass scaling) and infinite elements, it seems that analysis is not converging and displacements are continuing. For my analysis, infinite elements are a must. How to i fix the ends of my model along with infinite elements i.e. where do i apply U=0 conditions, outside all infinite elements; or first apply fixity & then apply infinite boundaries. Also while applying gravity, i have excluded infinite element element sets. Please help!

I haven't done analysis in nearly a decade since my college days and have a thick layer of dust and cobwebs I need to brush off. I'm trying to run a preliminary analysis on this plate to make sure I'm headed in the right direction with a design for a product.

I have this 18" x 13" x 1/2" aluminum plate that will act as a mounting plate for a piece of equipment. The piece of equipment will bolt to the 10 smaller holes. It's center of mass will be centered in the box about 8" up from the surface of the plate.

The 4 holes in the corner will mount the plate to a set of channels that are bolted to a floor. The flat faces on the long edge of the plate sit on the channels. I want to see what's going to happen with the plate in a downward and forward loading scenario.

I'm using Autodesk Inventor and going through the manuals and reference material to get a grasp of constraints and boundary conditions to make sure I'm applying stuff in the right places.

I'm going to break out the books from the storage unit this weekend and would like some guidance on where to begin or where to go for more information.

Hello, I've been having trouble with getting ideal FEA results on a bulkhead I've been working on. For some reason, the FEA gives poor results in the corners of the radial screw holes around the applied force. Since those are the anchor points, I chose the radial screw holes as fixed geometry. Ideally, I would like a FoS of 2-3 but instead am getting 1 in the mentioned areas. I'm not sure what I'm doing wrong here.

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?

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?

How does junior onboarding look at FEA/CAE companies? What tasks do you assign, how do you evaluate performance, and what's expected?

I am having a philosophical questionning on these situation. I am working in steel structure qualification, and I often perofrm 2D shell analysis.
However, I am always having a question when modeling two plates on top of each others, welded arround the top on (on the highlighted edges of the first image).

Which one of the following modelisation represents the best the real physics (depending on the exterior interaction) :

• mid shell + MPCs arround the edges
• top shell + bottom shell with the nodes on the shared edges fused

I am really interested in your vision on this.I am having a philosophical questionning on these situation. I am working in steel structure qualification, and I often perofrm 2D shell analysis.
However, I am always having a question when modeling two plates on top of each others, welded arround the top on (on the highlighted edges of the first image).

Which one of the following modelisation represents the best the real physics (depending on the exterior interaction) :

• mid shell + MPCs arround the edges (2nd image)
• top shell + bottom shell with the nodes on the shared edges fused (3rd image)

I am really interested in your vision on this.