Learning Forum

[Samar]

Hi Everyone

Please i would like to know what is the difference between using the ANSYS Workbench and Mechanical APDL in Meshing; As i used to draw a simple shape in workbench and mesh it, then draw the same shape in APDL with the same element type used in workbench and same element size. But i found a great difference in the Mesh of each one, Why ?!!!

[sathya]

Hi Samar,

As long as you make sure that shape,sizing and method chosen in both APDL & WB is similar,then you will get the similar mesh.

I have added few words on how ANSYS approaches Meshing in APDL & WB below.

You can use two different methods to generate your model in APDL: solid modeling and direct generation.

With solid modeling, you describe the geometric boundaries of your model, establish controls over the size and desired shape of your elements, and then instruct the ANSYS program to generate all the nodes and elements automatically. 

But the limitation of Solid modeling is

• Can sometimes require large amounts of CPU time.


• Can (for small, simple models) sometimes be more cumbersome, requiring more data entries than direct generation.


• Can sometimes "fail" (the program will not be able to generate the finite element mesh) under certain circumstances

By contrast, with the direct generation method, you determine the location of every node and the size, shape, and connectivity of every element prior to defining these entities in your ANSYS model.

But the limitation of direct generation method is

• usually too time consuming for all but the simplest models; the volume of data you must work with can become overwhelming.


• Cannot be used with adaptive meshing.


• Makes it difficult to modify the mesh (tools such as area mesh refinement, SmartSizing, etc. cannot be used).

In spite of the many advantages of solid modeling, you might occasionally encounter circumstances where direct generation will be more useful. You can easily switch back and forth between direct generation and solid modeling, using the different techniques as appropriate to define different parts of your model.

Meshing in Workbench follows different approaches and methods:

• Assembly meshing refers to meshing an entire model as a single mesh process, as compared to part-based or body-based meshing, in which meshing occurs at the part or body level respectively.

• Patch conforming meshing is a meshing technique in which all faces and their boundaries (edges and vertices) [patches] within a very small tolerance are respected for a given part.Patch independent meshing is a meshing technique in which faces and their boundaries (edges and vertices) [patches] are not necessarily respected unless there is a load, boundary condition, contact, Named Selection, result, or other object scoped to the faces or edges or vertices (topology).

• Meshing by Element Shape(Hex,Tet,Prism,Quad,Tri)

[Samar]

sathya 

Thank you for this great reply, i will check again what i have did.