Area Moment of Inertia for Solid Shafts

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SUMMARY

The area moment of inertia for a solid shaft is correctly defined as I = (π * d^4) / 64, with units in mm^4. The widerstandsmoment, W, is given by W = (π * di^3) / 32, measured in mm^3. The relationship between the area moment of inertia and the widerstandsmoment in bending and buckling scenarios is expressed as W_by = I_y / C, where C represents the maximum distance from the neutral axis to the outermost fiber. Understanding these formulas is crucial for accurate calculations in mechanical engineering applications.

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teng125
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for a solid shaft,the area moment of inertia is (pi*d^4) / 64 or (pi*d^4) / 32 ?? i mean in bending and buckling case.

ihave two formulas but don't know which one is correct??


does anybody has those formulas for other cross sections ??
pls help
 
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For a shaft with cross section d,

Area moment of inertia is I=\frac{\pi*d^4}{64} with unit mm^4

Widerstandsmoment, W=\frac{\pi*di^3}{32} with unit mm^3

Relation between W and I, for the case of bending and bulking, is given by:
W_{by}=\frac{I_{y}}{C} where C is the (maximum) distance from the neutral axis to the outermost fiber or layer of atoms.

Hence, do not be confused as they are different and yet related. If one is known, let's say I, the other can be found, W in this case.
 
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