> "J" is the polar moment of inertia.
For structural purposes J is the torsional stiffness. The polar
moment of inertia is the torsional stiffness only for the special
case of circular sections
>
> It is the square root of summation of square of moment of inertia
> about "x-axis" and "y-axis".
The polar moment of inertia is the sum of the cross-sectional moments
of inertia, not the root-sum-square
> You can find it in any standard Handbook.
Blodgett is your best resource. It explains everything
Just so you'll know.
Christopher Wright P.E. |"They couldn't hit an elephant at
chrisw@skypoint.com | this distance" (last words of Gen.
.......................................| John Sedgwick, Spotsylvania
1864)
http://www.skypoint.com/members/chrisw/
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