Hollow Rectangular Beams Deflection Calculation  

Where,
MI = Moment of Inertia
E = Modulas of Elasticity in psi
Example:
Calculate the deflection of hollow rectangle and its bending stress.
Length (Inches) = 5
Width (Inches) = 10
Height (Inches) = 15
Wall Thickness (Inches) = 5
Force (Pounds) = 10
Material = Steel
Solution:
Apply formula:
MI for hollow rectangle beams = (Width * Height^{3})  (Inside_width * Inside_height^{3}) / 12
Deflection = (Length^{3} *Force / (3 * E * MI)
Bending Stress = (Force * Length) / (MI / (0.5 * hHeight)
Deflection = 4.938271604938271e9 (Inches)
Bending Stress = 0.13333333333333333 (PSI)