# Young's modulus times second moment of area (1 Viewer)

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#### Pietair

Good day,

Im am wondering what you get when you determine the following of a bar during a bending experiment:

(E x I) / y

E = the Young's Modulus [kgf/mm^2]
I = Second moment of area [mm^4]
y = half of the bar height [mm]

Is there a name for this term? And what does this term represent?

#### Mapes

Homework Helper
Gold Member
The reciprocal of this term is the magnitude of the normal strain at the surface per unit bending moment (because $|\sigma_{\rm{max}}|=My/EI$). EI alone is called the flexural rigidity.

#### Pietair

Allright, thanks a lot.

Then I have got one question left:

In the formula:
(M/I) = (E/R)

What does "R" represent?

#### Mapes

Homework Helper
Gold Member
The radius of curvature of the bending beam.

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