Modeling an octogonal pole

[rubenpezu]

Dear All,
I am trying to model an octagonal pole for electric distribution. I have made by different ways but I want to know if it is possible make an extrusion with taper.
What I want to do is draw the base octagon (inner and outside) and the same in other plane with the top of the pole. And made an extrusion to create a pole. I have tried but I can’t do it. Is it possible?
When I model the pole by other ways I find a problem to fix restrictions. I can’t select the bottom area of the pole.
And other problem is when I made a small window in two opposite sides of the pole in order to help to evacuate water. It is demanded by one of our clients.
Thank you for your help.

 

[KhimaniMohiki]

you could extrude it with draft or maybe use swept with a scaling function?

Khimani Mohiki
Design Engineer - Aston Martin
NX8.5

 

[MustafaAsan]

Do you mean something like this?

 

[Toost]

If I understand you correctly, you want to create an "Extrusion" between two sketches,, ?

If so, the command is called "Thru Curves". An Extrusion in NX will not accept multiple profiles in different planes and in the same operation. (or at least not go between these.)


Regards,
Tomas

 

[mmauldin]

Attached is a zip file containing two part files showing various construction methods. "octopole" has several different methods including through curves and two methods of extrusions.

"octopole2_2" follows your desire to "draw the base octagon (inner and outside) and the same in other plane with the top of the pole". It uses two tapered extrusions controlled by reference lines drawn between the top and bottom sketches.

 

[carlharr]

A picture says a thousand words... and I can't open the OPs pic :-(

http://www.jcb.com

NX 8.5 with TC 8.3

 

[jerry1423]

If I am reading this correctly you will need to do it in two steps, instead of one

Here is something simple that I came up that I think is similar to what you need.

 

[rubenpezu]

Dear All,

thank you very much for your help. All your comments have been very useful.

MustafaAsan It is just what I want. I have done one just like these but I have problems when I mesh. I can’t select the right surface to fix the restrictions.

Toost It is exactly what I try to do. I will try with your indications.

Mmauklin, your second file is just what I was trying to do. When I create a mesh and put the restrictions It works well. I will try to create the window I need to evacuate water and I will see how it works.

Jerry1423, your file is what I was looking for. I will try to create the window I need to evacuate water and I will see how it works.

I will work wiht all of this and try to make my analysis.

Thanks.

 

[rubenpezu]

One thing more. I need to have a constant thickness in the pole.

 

[carlharr]

Constant wall thickness like this? I've used offsets mainly, you can see in the user expressions and in the sketches.

http://www.jcb.com

NX 8.5 with TC 8.3

 

[rubenpezu]

Great solution carlharr, It is just what I need but in order to resolve the analysis I need to fix a pole in an imaginary line in the middle in the hole. As if the pole is buried in concrete.

I have made my model with and extrusion and later making a shell. In my model when I messh I can't select the top and the bottom surface. Why? And I need to apply the wind pressure, how I have to apply? With hidrostatic pressure and changing the values? Sorry but is my first month with this software.

 

[carlharr]

Hi, extrude and shell is another good way to make your model, if you'd rather control the side angle instead of the two end sizes.
There are many different ways to model depending on your "design intent".

As for analysis - it's all beyond me (apologies), although your mesh looks sharp rather than flat at the bottom. Smaller triangles?? (total guess)

http://www.jcb.com

NX 8.5 with TC 8.3

 

[mmauldin]

For a constant wall thickness I would use the shell command. Using an offset on a tapered extrusion doesn't give a true wall thickness. On a very shallow taper it doesn't make a lot of difference, but it is there. See attached:

 

[carlharr]

Agreed mmauldin, I ditched extrude as well and went for swept instead.

http://www.jcb.com

NX 8.5 with TC 8.3

 

[carlharr]

Just thought I might as well shell my swept feature, instead of using an internal swept and subtract.
So I tested it and errrrr, very odd! Never seen shell do that before.

http://www.jcb.com

NX 8.5 with TC 8.3

 

[JohnRBaker]

When you create your 'Swept' feature be sure to use the 'Alignment Method' of 'Parameter' and then in the 'Settings' section of the dialog, toggle ON the 'Preserve Shape' option. This will allow you to get a proper result when you 'Shell' your model.

John R. Baker, P.E.
Product 'Evangelist'
Product Engineering Software
Siemens PLM Software Inc.
Industry Sector
Cypress, CA
Siemens PLM:
UG/NX Museum:

To an Engineer, the glass is twice as big as it needs to be.

 

[cowski]

carlharr,
You might think that the outside of your octogon has 8 faces, but it does not. The swept feature is approximating your input with splines and the shell feature is exaggerating what happened with the approximation. In your picture, you can see a black "edge" line at the top right side, but there is no "edge" line at the next corner (moving clockwise around the octogon).

Try turning on "preserve shape" option in the swept feature and check the results.

www.nxjournaling.com

 

[rubenpezu]

According my model I should round the corners of the pole because of the difference between the perfect model in NX and the reality when you manufacture.

I have mesh wiht CTETRA(4) tool, do you think is right? With this way my octopole is perfect to fix de areas I want. When I use CTETRA(10) I have problems as I have shown before. My mesh looks sharp! Could anyone explaim me de difference between use CTETRA(4) or CTETRA(10)?

 

[rubenpezu]

I forgot show my mesh.

 

[carlharr]

John and cowski, you're correct I was tricked, subtle difference but it's there!

http://www.jcb.com

NX 8.5 with TC 8.3