Connecting mid-surfaces

Rahul_P1

Hi all,

For my project I need to do some linear static analysis on the cab of the truck. I am using HyperMesh as pre-processor and for solver probably I am going to use RADIOSS bulk format.

I received CAD model in IGES format. I imported the geometry directly to HyperMesh. Because of thin walled structure I am going to use 2D shell elements. So far I created mid-surfaces from 3D parts and I did some geometry simplification. My current situation now is that I have around 30 mid-surface components with little gaps between them due to reducing from 3D to 2D (no thickness).

My problem is I don’t know exactly how to proceed. Is there any special tool in HyperMesh to put all of the mid-surface components together and make them connected? I could translate all the components manually (tools>translate) but it takes a lot of time. Or maybe do you suggest me to leave the gaps between the components and use the connectors?

I don’t have experience working with so many components. So far I worked with max 3 components and usually I just equalized surface edges between components or something similar.

Thanks

Rahul_P1

Ziga,

auto midsurface extraction options can be used to better extract midsurfaces,

Read HyperWorks Desktop Applications > HyperMesh > User's Guide > HyperMesh Panels > HyperMesh Panels Listed Alphabetically > Midsurface Panel > auto midsurface extraction options

Depending on the geometry you may in certain cases have to repair your midsurfaces after extraction, can you paste an image of your model with the gaps showing?

Read HyperWorks Desktop Applications > HyperMesh > User's Guide > HyperMesh Panels > HyperMesh Panels Listed Alphabetically > Midsurface Panel > Repairing Areas where Automatic Extraction Failed

Rahul_P1

Probably I was not clear enough. I have an assembly of 30 part- 3D parts. I created mid-surface from each part separately to have better control of mid-surface. So now I need to attach all those parts together. My question is what is the best option doing it? So far I used translate and surface edit (offset, extend) panel but it takes a lot of time. Is there any special tool in HyperMesh?

I attached one figure. Left side represents 3D- parts are connected. Right side shows mid-surface (2D) of each part with gap between them. What is the best to connect 2D parts together?

Thanks a lot.

Rahul_P1

Ziga

There are several ways,

However the best approach is to clean up the geometry and then try the various auto midsurface options,

From your image I suspect the insert planes option may solve your problem,

HyperWorks Desktop Applications > HyperMesh > HyperMesh Tutorials > Geometry > HM-2015: Auto-Midsurfacing with Insert Planes

You can use surfaces > ruled to create surfaces between two lines, or spline / filler wherever missing surfaces are surrounded by free edges on all sides

you can use surface pair of the midsurface panel to extract midsurfaces at the places where there are missing surfaces, basically you will need to select the two surfaces between which you need a midsurface created,

As a side note - Meshing experts would start meshing and fill the gaps with the 2d page meshing options such as ruled to save time, because the end result you are looking for is the mesh.

Altair Forum User

What are the applications of midsurface concept

 

Simon Križnik

@Ravikumar nelwale

 

Use the Midsurface panel to extract the midsurface representation of a solid part or to generate a finite element shell representation of a solid geometry. This panel can be used to extract the midsurface of sheet metal stampings, molded plastic parts with ribs, and other parts that have thickness clearly smaller than width and length.