r/ANSYS_Mechanical

I'm trying to create an analysis on hull of a boat. When i try to pull it created multiple bodies instead of 1 body for the water. How do I rectify this.

Hi everyone,

I'm running an Explicit Dynamics simulation in ANSYS Mechanical. My model consists of an impactor, supports, and the main specimen(beam)

When I change the Stiffness Behavior of the impactor and supports from Flexible to Rigid, those bodies immediately become Undefined, and a question mark appears next to them in the Geometry tree (shown in the screenshot).

If I leave them as flexible, everything works normally. The issue only happens after I set them to rigid.

Has anyone run into this before? I'm trying to figure out whether it's caused by the geometry, contacts, material assignment, body interactions, or something else.

I'd really appreciate any suggestions on what I should check. Thanks!

Hi everyone,

I am working on a plastic design task where I need to design a cover/lid that locks onto a mating plastic component.

The locking feature is inspired by a concept used in some existing products, but I have been told that it may not really be a classic elastic snap-fit. It may be closer to an interference/deformation locking feature, since the intention is that the cover should stay assembled permanently.

One difference in my current design is that the mating line/interface is not flat. The cover has to lock around a more 3D/organic surface, which makes the geometry harder to evaluate.

I have made a 3D printed PLA prototype of the concept, and mechanically it seems to work quite well. The cover can be pushed into place, it locks firmly, and I need a tool to remove it again. However, the final part will be injection molded in PP, which is softer and more flexible than PLA.

So I thought this could maybe be a good opportunity for me to use FEA on a real design case and use it as a learning opportunity to understand how this type of problem could be approached via FEA.

I only have basic university experience with ANSYS Mechanical, mainly static structural simulations, so I am trying to understand what a realistic first simulation approach would be.

My questions are:

1. Does it make sense to simulate the assembly of this type of plastic locking feature as a learning and design exercise. If yes, what useful information could I realistically get from the simulation, snap deflection, insertion/removal force, contact pressure, or critical strain areas?
2. What would be the correct approach for this? My initial thought is that it should be treated as a nonlinear contact analysis with large deflection. However, since the cover has to move into position during assembly, I am unsure whether this can still be done as a static structural analysis using prescribed displacement, or if some kind of dynamic analysis would be more appropriate.

Any advice would be appreciated.

Hello Guys, I am a Mechanical Engineer currently working on CFD projects.

I recently completed a Computational Fluid Dynamics (CFD) project of a client focused on the design optimization of a Shell-and-Tube Heat Exchanger using ANSYS Fluent.

🔹 Project Objective To improve heat exchanger thermal performance through progressive design modifications and validate CFD results against theoretical calculations based on the LMTD (Log Mean Temperature Difference) method.

🔹 Design Evolution

✅ Design 1: Basic Double-Pipe Heat Exchanger

✅ Design 2: Added Tube Headers, End Plates, and Flow Management Components

✅ Design 3: Introduced Baffles to Enhance Cross-Flow and Improve Heat Transfer

✅ Design 4: Replaced Single Tube with a 5-Tube Bundle while Maintaining Equivalent Flow Area• Increased heat transfer surface area by approximately 123%

✅ Design 5 (Final Optimized Design):• 5-Tube Bundle• 8 Internal Baffles• ~2.84 Million Computational Cells• SST k-ε Realizable Turbulence Model• Complete CFD Validation Against Analytical Calculations

🔹 Pre-Simulation Engineering Calculations

Using the LMTD method, the operating conditions were determined as:

• Shell-side Velocity: 0.00658 m/s• Tube-side Velocity: 0.01492 m/s

These values were then used as boundary conditions for CFD simulations and validation.

📊 Validation Design 5 produced the closest agreement with theoretical predictions:

• Shell Outlet Temperature: 387 K(Target: 350 K | Error: 10.6%)

• Tube Outlet Temperature: 382 K(Target: 400 K | Error: 4.4%)

Compared to Design 1, the shell-side prediction error was reduced from nearly 29% to 10.6%, demonstrating the effectiveness of the design optimization process.

🔹 Verification A mesh independence study was conducted using coarse, medium, and fine meshes. Temperature variation between medium and fine meshes remained below 0.01%, confirming numerical reliability and solution stability.

This project was a great exercise in combining:✔ Heat Transfer Theory✔ CFD Simulation✔ Design Optimization✔ Numerical Validation✔ Engineering Problem Solving

If you want to learn more about the project or get the hands on guidance on the project for Free, do let me know in my dm. Thanks

Anyone knows how to calculate linear hardening/softening part?

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And which one is better for solid 185 and grout menetrey-williams or drucker-prager?

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And should I have a miso table with this code or not?