As an example, an irregular section located on 0,0; the centroid
will be specified as -0.023,-0.01
You will have to hand calc the section modulii (Sx top, Sx btm, Sy
left, Sy right). No big deal as you have all the information required
in the output.
Send reply to: seaint(--nospam--at)seaint.org
From: "vicpeng" <vicpeng(--nospam--at)vtcg.com>
Subject: Re: Autocad Section Property Calculation
Date sent: Wed, 31 May 2000 07:08:52 -0700
> Ahh yes. Thanks. That makes the example I have make sense. But how do I get the real centroid of the section, i.e. where is 0,0 with respect to the section?
> Thor A Tandy P.Eng
> Victoria BC
> e-mail: vicpeng(--nospam--at)vtcg.com
> ----- Original Message -----
> From: Jake Watson
> To: seaint(--nospam--at)seaint.org
> Sent: Wednesday, May 31, 2000 6:16 AM
> Subject: Re: Autocad Section Property Calculation
> Make sure the object centroid is at 0,0. Autocad calculates all
> properties about that point. If you have a 2x4 at 10' from the origin,
> you will get a very large inertia. Then other option is to use the
> parallel axis theorem and subtract out the ad^2 term by hand to account
> for the displacement.
> Jake Watson, E.I.T.
> Salt Lake City, UT
> > vicpeng wrote:
> > I have a feeling that this might have been posted before.
> > In AutoCAD under "massprop" the section properties such as area,
> > perimeter, centroid, Moment of Inertia etc are calculated.
> > I did a check on a complex section by hand and I found that AutoCAD
> > produces a different answer from mine for the Moment of Inertia. The
> > other values appear correct but not "I".
> > Does anyone know if I did something wrong or what AutoCAD is doing?
> > This is not my software so the licensee may have set up something in
> > the program??
> > Thor A Tandy P.Eng
> > Victoria BC
> > Canada
> > e-mail: vicpeng(--nospam--at)vtcg.com