Software That Calculates Section Properties 11

[Lina]

I am using Shape Builder to calculate section properties of complex shapes. However shape builder is limited to predrawn shapes and the program does not allow you to draw your own shapes. does anybody know of a more flexible program.

Thanks.

 

[qjchen]

many fem software can calculate the section property

such as -algor -ansys -pro/e etc.

and a simple way is use acad

when you draw a object , define it as "region"

and you can use query "mass property" to get it

good luck

 

[arnie]

Robot have a package called Section Definition which allows you to define any shape either from sticking sections from predefined databases together or by drawing free form contours and also thin walled sections.

The results can be exported in text file format so you are not limited to just using this package with the bigger Robot system.

 

[JAE]

Lina:

Look in

http://www.risatech.com

They just came out with a section property program.

Also, in ShapeBuilder, I believe you can piece together various rectangular shapes to get almost any shape you want.

 

[butelja]

Draw the section in Autocad. Convert the closed section to a region. Use the MASSPROP command and pick on the region. It will give the the moments of inertia, centroid, and area RELATIVE TO THE CURRENT UCS. To find section properties move either the region or the UCS origin after the first MASSPROP so that the centroid location is 0,0,0. Running the MASSPROP a second time and you will get the true section propertis.

If you are doing FEA, then the FEMAP pre/post processing software has a nice utility built in for this.

 

[Lina]

qichen
I have been using AutoCad for 10 years. I knew about the area and the perimeter but I never experienced Mass Property. This is great. Thanks for a great tip. And thanks for Eng-Tips...
Do you have contact information for the software you have listed

Jae.
I will definitely check on this software.
If you use complex shapes with shape builder the presentation of the drawing is not good. But the program is great in finding values .
Thanks

 

[JAE]

We are seriously looking at the RISA Shape Program for just that reason, Lina. ShapeBuilder is quite versatile but sometimes rather cumbersome to "build" a section. When clicking on a piece of your shape, the mouse always drags the piece to one side and you are continually UNDOing the drag. Otherwise, we like it. The RISA product is great because it takes your shape and automatically writes it into our RISA analysis/design software packages.

 

[yakpol]

Lina, if you can describe your section by the node coordinates, then you can try the spreadsheet 'sectprop.xls' at

http://yakpol.net/

 

[Lina]

butelja

Thanks for the tip. However I have one question.
How do you find the center og gravity for the drawn shape in autoCad.

Thanks.

 

[chandr]

Try dwld Prokon. Only the basic modules are fine. After getting into the cross-section module, click examples. The output of this module is quite nice.

 

[Lina]

butelja

I was able to find out how to calculate the center of gravity in AutoCad. Thanks ....

 

[butelja]

Lina

The MASSPROP command will give the x,y,z coordinates of the centroid, which is the same as the c.g. A sample of the MASSPROP command is shown below:

Command: massprop

Select objects: 1 found

Select objects:

---------------- REGIONS ----------------

Area: 3.6740 sq in
Perimeter: 22.2938 in
Bounding box: X: 0.0000 -- 4.0000 in
Y: 0.0000 -- 4.0000 in
Centroid: X: 2.0000 in
Y: 2.0000 in
Moments of inertia: X: 24.7033 sq in sq in
Y: 17.8741 sq in sq in
Product of inertia: XY: 14.6959 sq in sq in
Radii of gyration: X: 2.5930 in
Y: 2.2057 in
Principal moments (sq in sq in) and X-Y directions about centroid:
I: 10.0075 along [1.0000 0.0000]
J: 3.1783 along [0.0000 1.0000]

 

[SWang]

You can down load a free program at

http://www.Lanxun.com/pce/download.htm

 

[blueprint]

If you want to draw your custom sections (solid or hollow)parametrically in 3D try

http://steelstubs.bizland.com

Peter.

 

[jameslord]

Hi,
I am using the ShapeDesigner software to calculate the section properties and the stresses analysis it's really very interessting and flexible we can import dxf complexe geometry etc.. and calculates also the tosion (J) and warping (Cw) constants.


i hope this helps


James

 

[mrMikee]

When using AutoCAD to determine section properties it is important to move the cg of the shape to the 0,0 point in order to get the radii of gyration correct.

Note in the above example by butelja that the 0,0 point is at the lower left of the shape as indicated by the bounding box. This means the product of inertia and radii of gyration will be computed about the lower left corner and not the cg which is what you want for calculations. I always do this in two steps. First run MASSPROP to find the cg, then move to the cg and run the MASSPROP again.

When done I generally cut and paste the info from the command window into the drawing and print out for my records. If I don't move the cg I found it is too easy to forget the radius of gyration shown is not correct for stress calcs.

Regards,
-Mike

 

[mrMikee]

butelja:

As I scanned through the messages again I realized that I had missed the point you made in your first post in which you explain the centroid 0,0 location issue. Sorry about that.

A momentary lapse of reason.

Regards,
-Mike

 

[Viraf]

Lina

I have a simple program that calculates section properties - moment of inertia, centroid, plastic section modulus - by inputting node co-ordinates of your cross section - solid or with holes.

Viraf