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What's wrong with my integration to calculate section properties

AH_10884969
4-Participant

What's wrong with my integration to calculate section properties

I am developing a sheet to calculate section properties of steel sections using Mathcad Prime 10, however I find the integration gives zero value for web thickness less than a number for my specific example. 

 

see below screenshot and attached file. The Ay gives correct area, however the Ax doesn't. I have tried different values for tw which gives a correct result when it is larger than a certain number. For example in the I section if changed to 30mm, the integral gives correct answer. 

 

AH_10884969_0-1736298599735.png

Appreciate any help please. 

ACCEPTED SOLUTION

Accepted Solutions

9 REPLIES 9
LucMeekes
23-Emerald III
(To:AH_10884969)

What is a right result, and what is wrong? It would be nice if you specify what you expect (versus what you get).

Your definition:

LucMeekes_0-1736325472675.png

is overlapping.

The first row sets a value when -0.29m < x < 0.29 m and the last row sets a value when -0.77m < x< 0.77m.And the two middle rows specify the same range. So you get:

LucMeekes_1-1736325674496.png

 

 

Is that intentional?

 

Success!
Luc

AH_10884969
4-Participant
(To:LucMeekes)

The formula and the integral calculate the area of the steel section below. The total area should be 202550mm2, however the formula calculates it 141800 which basically the total flange areas. The web area is not calculated (second and third rows). 

I don't intend to have it overlapped, I am just unsure how to do it. 

 

AH_10884969_0-1736376602336.png

 

Hi,

Try this method of calculating section properties.  Starts with definition of the section by xy coordinates

Cheers

Terry

 

Capture.JPG

Thanks Terry, that looks like to be the answer I am looking. 

 

Is there a way to use integral for the calcuations?

Hi,

Example provided by you shows you can use integral but why complicate a simpler solution.

Have been using the generic section calculator since Mathcad 6 it works fine

Cheers

Terry

Thank, yes, your solution looks to be simpler and easier to work with.

Hello @AH_10884969

 

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Vivek N.
Community Moderation Team.

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