element and Mesh Variation

[analyst89]

Can anyone explain briefly why different types of meshi patterns like shell,solid,hex,tria or ortho tria used for a single analysis?

Not a single time but for the same analysis there are many different mesh patterns being used. why is it so ?

 

[rb1957]

it depends on what you're meshing ... is it a surface (shells, quads and tris) or a volume (solid, 3D, elements).

you're also using the phrase "mesh patterns" in a way i've never heard before. in my experience the term refers more to the appearance of the mesh, the density of the nodes, rather than the elements used.

 

[analyst89]

Thats Right man,

We use shell and solid but the thing is that why the need for different elements.. i.e. for a single durability analysis we can employ diifernt global sized mesh with varying elements like shell as wll as tet or ortho tria mesh.. why is it is so nad how it will have its effect on the analysis?

Also i am a novice in this field which i have had my hands till modelling only.. so let me know your thoughts about this !!

 

[Piyush88]

single analysis emplys different elements depending upon the geometry in use....
If u want to analyse a solid pole with a thin disc attaced to it....
SO u have to use Solid elements 4 meshing the pole. and Shell elements for the THin disc

Element selection depends on the geometry and the behaviour of the structure to be anlysied

 

[rb1957]

a surface is 2D, yes, it can be in any 3D shape but it has length and bredth dimensions only (ie 2D), so you can only give it 2D (ie thin) elements.

if you want to fill the volumen enclosed by a suface, now you're talking a 3D shape, and you have to use 3D (ie solid) elements.

it's a different question if you're asking tri or quad. Generally quads are better than tri, they suit the math better. but quads can have difficulty mapping surfaces (4 points don't make a flat plane); tris can mapp any surface (3 points define a flat surface) but their results can be "suspect".