**shear stress in hollow beam**
I m going to find the shear stress at section n-n .
So , shear stress in beam has formula of τ = V(Ay) / It
I gt the I ( second moment of inertia correctly ( same as the given ans ) , but I'm having problem of finding the shear stress at A .
For V ( shear force ) , it is 40kN constant from 0m to 0.4 m ( in my SFD diagram)
For Ay , i have (100x10^-3)(12x10^-3) (94-50)(10^-3) = 5.28x10^-5 (mm^4)
Is my Area ( green coloured part ) correct ?
so τ= (40x10^3) ( 5.28x10^-5 ) / (5553152 x 12x10^-3) = 3.81x10^-6 , but the given ans is 15.85x10^6
Does the section n-n mean when we cut off the beam at n-n , the side view of n-n look like in the diagram ?
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Last edited by ling233; Nov 4th 2016 at 10:07 AM.
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