Question

A beam is made of two identical metal flats soldered together. What is the ratio of stiffness of this beam to the stiffness of a beam in which the two flats are not soldered and which acts independently?

• A. 2
• B. 4
• C. 6
• D. 8

Answer 1

The correct option is B 4

Stiffness of a beam is directly proportional to the moment of inertia of the cross section about its centroidal axis.

$\frac{Stiffnessofsolderedbeam}{Stiffnessofunsolderedbeam}=\frac{\frac{b(2d{)}^3}{12}}{2\times \frac{b{d}^3}{12}}=4$