SHEAR STRESS The shear distribution along the cross section of the beam can be found by taking the shear stress at different heights, using values from the shear diagram (V), and the statical moment of area (Q), over the moment of intertia (I) and the breadth of the cross section (b). FV
= VQ / Ib
V
= 304 N
Q1
= 9 mm (10 mm)(4.5 mm) = 405 mm3
Q2
= 4.5 mm (10 mm)(6.25 mm) = 281.25 mm3
I
= 4 860 mm4 [from bending stress calculation]
b
= 10 mm
[from shear stress diagram]
With the variables established, the maximum shear stresses in each section of the beam can be calculated. @ level 1 FV1 = (304 N x 405 mm3) / (4 860 mm4 x 10 mm) = 123 120 Nmm3 / 48 600 mm5 = 2.53 MPa
@ level 2 FV2 = (304 N x 281.25 mm3) / (4 860 mm4 x 10 mm) = 85 500 Nmm3 / 48 600 mm5 = 1.75 MPa
Shear Distribution Diagram