ANSYS Meshing - Lunch & Learn

Title: ANSYS Meshing - Lunch & Learn Recording - August 27th, 2015 It's not like making it happen, but more saying, "What can you make it happen?" That's what I feel. All right. All right, well, good morning, good afternoon, everybody.

So today we are going to talk about meshing, which enhances our work. We will primarily focus on work mesh meshing here. So thanks for showing up. Please help yourself with the food. There's a lot of pizza here. And we'll just get going. We are Ozen Engineering, the ANSYS distributor here.

We are also a consulting company that gets into a lot of FEA and CFD type of problems. We provide sales, marketing, training, and advanced simulations like rigid body dynamics, rigid-flexible implicit dynamics, and explicit dynamics. We specialize in fracture mechanics and CFD.

Our next lunch and learn will be on fracture mechanics, covering crack initiation, crack propagation, crack modeling, cohesive zone elements, contact elements, and the XRAM method, which is meshless fracture mechanics. When it comes to meshing, this is a special topic.

Some of you do meshes for fracture mechanics applications. We will cover this more in-depth in our next lunch and learn. So that will be about two or three weeks from today. There's really a lot of new stuff in ANSYS when it comes to fracture mechanics.

We'll cover all that new stuff in our next lunch and learn. But today we are going to talk about ANSYS and its meshing methods. We will discuss preprocessing workflow in ANSYS, meshing fundamentals, and how to launch ANSYS meshing.

We'll also talk about ANSYS meshing methods and how to morph the mesh without going for a re-mesh procedure.

The preprocessing workflow in ANSYS involves checking data up to possible tenants, starting with the geometry, importing or creating it, then doing geometry modifications, cleaning up, and simplification.

We idealize the geometry during the geometry phase and fill the solid model with elements during the meshing phase. Then, we send the mesh into the solver, either for CFD or FEA, such as rigid body dynamics or implicit dynamics.

ANSYS meshing combines and builds on strengths from pre-processing tools like ISM CFD and TGRID. The new management at ANSYS took a look at the technology and added it to their portfolio. They also bought CFX, which led to a climb in the ANSYS stock.

We are in version 16 of ANSYS, and there's really a lot of new stuff when it comes to fracture mechanics. In version 16, ANSYS meshing includes all the good stuff from iSIM CFD, CFX mesh, Gambit, and T-Grid.

You can still launch iSIM CFD just by itself, but almost all of the features of iSIM CFD are available through ANSYS meshing. ANSYS meshing can build meshes for CFD, mechanical, and electromagnetic applications and integrates nicely with other Workbench systems.

The purpose of the mesh is to solve equations at the cell or element locations. Nowadays, people use one platform for both CFD and FEA meshing. We should be able to create meshes in a fast, efficient, and accurate manner, with high-quality meshes.

In the next few slides, we will talk about all these aspects. You will notice a 10% improvement in mesh creation speed in version 16 compared to version 15. ANSYS came up with three versions in 2015: 16.0, 16.1, and 16. 2. Most of the differences are in a brand new product called AIM.

We will focus on ANSYS meshing in Workbench. You can specify global mesh settings, local mesh settings, generate the mesh, and check the mesh quality. You can launch ANSYS in Workbench from the analysis systems or from scratch under component systems. There are a few ways to configure your geometry.

You can use multiple parts, multi-body parts, or design modeller to form multi-body parts. The connection point between the two cubes will be an imprinted face in multi-body parts. Meshing in 3D geometry offers TETs, PRISMS, PIRAMIDS, and HEXES element types.

You can use tetrahedral meshing, sweep meshing, or multi-zone meshing methods. We will cover TED meshing and HEX meshing methods. TED meshing has two options: patch conforming and patch independent.

Patch conforming obeys all the details in the geometry, while patch independent puts nodes and elements on the surface, ignoring some details. The OCTree mesh provides an approximate growth rate, while the Delanoi mesh offers a smooth growth rate.

You can choose between these methods based on your requirements. Hex meshing requires extra time for cleaning the geometry and may require geometry decomposition for a nice hex mesh. Sweep meshing is the best option if your geometry lends itself to that method.

Multi-zone meshing is a methodology from ISIM CFD that provides a really nice hex mesh in geometries that are not sweepable. It's getting better every year, with more automatic features being added.

Local mesh controls allow you to specify sizing, contact sizing, refinement, mesh control, pinch, and inflation. You can specify these controls after setting the global mesh controls. When you're done with meshing, check the mesh quality.

Bad mesh quality can cause convergence difficulty or diffuse the solution. You can check things like orthogonal quality and boundary layers. In FEA, a bad mesh can cause convergence difficulty or produce incorrect results. If you see a local hot spot, check the quality of the mesh.

Remesh it with a nice set of elements for a smooth solution. Check aspect ratio, skewness, and warping for a good mesh. Aspect ratio is the height of the element divided by the width of the element. If the aspect ratio becomes more than 10, you're almost guaranteed to get bad results in FEA or CFD.

In version 16, right after you mesh, you can plot the element quality. You can right away tell where you have bad elements. You can pick a node and move it to make it a good element just by moving it. In FEA, you can specify a different thickness for shell elements and display the shell thickness.

The default settings in version 16 give you a better-looking mesh by default. Adaptive remeshing is really great for FEA problems where you're inserting something in tight spaces. It meshes refine where needed during the solution process.

This procedure existed in ANSYS Classic but is now available in Workbench as well. Finally, we'd like to talk about the VGA solider joint reliability sensitivity simulation using RBF morph. This technology originated in Fluent and is now available in ANSYS meshing.

You can pick a surface and make it parametric, adjusting the mesh so that you can extend it, scale it, rotate it, or offset it without remeshing. This is useful for sensitivity analyses in ANSYS mechanical.