Advanced Mesh Morphing in ANSYS Mechanical

It is a great pleasure to guest blog for ANSYS again after my post in 2014 entitled Reshaping the Future of CFD Using Mesh Morphing. We continue to increase our commitment to deliver the high-performance mesh morphing technology of RBF Morph and began our new product project at the beginning of 2014.

We presented the first industrial applications at the Automotive Simulation World Congress in Tokyo in October 2014, and officially launched the RBF Morph ACT Extension on the market at the ANSYS Italian UGM in May 2015. At the end of 2015, we posted a free version (with limited functionality) in the ANSYS App Store.

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Try the new RBF Morph ACT Extension available in the ANSYS App Store

Currently, the App is designed to work with ANSYS Mechanical. Morphed meshes could of course be linked to other analysis systems and used by other solvers directly on the ANSYS Workbench project schematic.

The basic idea of mesh morphing is to adapt a new shape for the part to be studied by updating nodal positions while keeping the same topology, i.e. leaving the element and node count unaffected. A good morpher should carefully capture the desired modifications at controlled surfaces while preserving mesh quality that is good enough to enable reliable solution of the numerical model.

RBF (Radial Basis Functions) mesh morphing is acknowledged as one of the best because it allows local control (node wise) and nicely preserves the quality. Under the hood of our extension is a high-performance RBF library based on fast algorithms and powered by the use of parallel calculation (including multicores and GPU).

Mesh morphing paradigms based on RBF have immense undiscovered potential; the RBF Morph Add-On for ANSYS Fluent, launched in 2009, was the first industrial software based on this technology. In the ACT Extension, we introduced many of the concepts that are in the Add-On but started from scratch with a new idea for the GUI which is embedded in the tree and works with the same “look and feel” as the host application. A hierarchical morphing can be enabled and the nodes of the mesh that are used to control the morphing (sources) or that are controlled by the morphing action (targets) can be selected using all the powerful scoping tools of ANSYS Mechanical (by geometry, by mesh and by named selections).

Basic modifications (translation, scaling and rotation) can be used to individually control different areas of the mesh; more complex modifications can be created by hierarchically chaining the basic ones (translation of individual points can control an edge; edges can control surfaces, and so on). Advanced modifications (surface offset, curve offset) allow effective control of a complex assembly. And, CAD-based modifications (surface target, curve target) can be introduced to precisely update portions of the mesh onto the desired shapes.

The user can also control how the modification interacts in the case of sequential actions and overlapping targets. The results is an expressive and flexible tool. And, when curious users try to push the morphing concept to the limit, they discover new, helpful ways to use the RBF Morph extension and its powerful features that were not in the product specifications.

Using the RBF Morph ACT Extension, SACMI performs mesh-based shape optimization with ANSYS Workbench to overcome parametric CAD-based shape optimization limits. In the example, the thickness of the grey component is changed by preserving the contacts of the whole assembly.

The mesh is updated when the project is solved and so calculation is conducted on the desired shape. Because parameters can be enabled everywhere in the tree (and in the definition of the target geometry) design exploration becomes as easy as that in ANSYS Workbench.

Advanced users skilled in ACT customization can also take control of some nodes, for instance, using stress level as an input to define how much to move nodes inward or outward with respect to a surface, or to control the reshaping of a crack profile in fracture mechanics. If you don’t know what ACT is, you should learn more! ACT allows you to quickly and effectively code new functionalities and to easily distribute them as Apps that can be installed and used. And this is exactly what we have done with RBF Morph ACT Extension. You just need to download and install it. And you can easily uninstall unused Apps… but please, don’t do that with the RBF Morph Extension!

 

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