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-   -   Is Section Modulus the same as a cross sections bending strength modulus ? (http://www.physicsforums.com/showthread.php?t=325592)

Mech King Jul17-09 10:22 AM

Is "Section Modulus" the same as a cross sections "bending strength modulus"?
 
Good afternoon everyone,

I am following an ECE directive that sets out the requirements for the properties of a "Rear underun protection device" for the rear of a lorry.

It states that the underun bar must consist of a "steel beam whos cross-section has a bending strength modulus of at least 20cm^3"

Are they refering to the "Section modulus"? or is what they are stating a completly differnt entity.

Trying to find the appropriate person to speak to for this directive is proving abit of a nightmare, oh the joys of bureaucracy eh!

What are your thoughts?

Mech King

Nick Bruno Jul17-09 12:17 PM

Re: Is "Section Modulus" the same as a cross sections "bending strength modulus"?
 
From the looks of the information given, I would say it is indeed the section modulus because the unit is volume.

I believe bending strength modulus is the same as flexural modulus defined as:

EI or N/m^2 * m ^4 = N*m^2

Please correct me if i am wrong, but this is my take on this.

nvn Jul18-09 12:00 PM

Nick Bruno: No, flexural modulus of elasticity has units of Pa (pascals), as does tensile modulus of elasticity. And E*I, which has units of N*m^2, is called flexural rigidity, not the names you listed.

Mech King: I agree that "bending strength modulus" in your above post is elastic section modulus.

Mech King Jul20-09 05:52 AM

Re: Is "Section Modulus" the same as a cross sections "bending strength modulus"?
 
Thanks for your replies chaps,

much appreciated.

Cheers


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