Second moment of area about the horizontal axis

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Discussion Overview

The discussion revolves around calculating the second moment of area for a beam, including related calculations for shear flow and local variables. Participants share their methods and results, seeking validation and assistance on specific calculations.

Discussion Character

  • Homework-related, Technical explanation, Exploratory

Main Points Raised

  • One participant requests help in calculating the second moment of area for a beam.
  • Another suggests dividing the beam into parts and summing the moments of area for each section.
  • A participant shares their calculation result of 172.8 *10^6 mm^4 and asks for confirmation of its correctness.
  • One participant affirms the correctness of the previous calculation.
  • Another participant discusses their local variables for calculating shear flow and seeks feedback on their setup.
  • Responses indicate that the local variables appear reasonable.
  • Participants share progress on calculations related to shear flow and the shear center, with references to specific calculations for s1, s2, s3, and s4.
  • There is an inquiry about how to determine the shear center based on the calculations shared.

Areas of Agreement / Disagreement

There is some agreement on the method of calculating the second moment of area, but the discussion includes multiple calculations and methods for shear flow and local variables, indicating that not all aspects are settled.

Contextual Notes

Participants' calculations and methods depend on specific assumptions and definitions that are not fully detailed in the discussion. There are unresolved steps in the calculations related to shear flow and the shear center.

Who May Find This Useful

Students and professionals interested in structural engineering, mechanics of materials, and related calculations involving moments of area and shear flow.

vtaela
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Could someone help me on how to calculate the second moment of area of the beam in the figure below?

ImageUploadedByPhysics Forums1362933459.410910.jpg


Thank you
 
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hi vtaela! :wink:

divide it into parts, and add the moment of area of each part

show us what you get :smile:​
 
my calculations give me 172.8 *10^6 mm^4

is that correct?

thank you
 
vtaela: Excellent work. Your answer is correct.
 
I am trying to find my local variables in order to calculate the shear flow! I have the local variables as shown below! Are my local variables set correct?
ImageUploadedByPhysics Forums1363000995.952013.jpg

Thank you
 
Looks reasonable.
 
I finished with this, look similar to what you got?
 

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Working out of ixx
 

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Flow diagram and calculation of s1
 

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  • #10
Calc of s2, s3 and s6. The first picture i posted is calc for s4 and final value. Any idea how to do shear centre?
 

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