Question

A 30 mm thick AISI 1020 steel plate is sandwiched between two 10 mm thick 2024-T3 aluminum plates and compressed with a bolt and nut. The bolt is M10 × 1.5 and the length of the bolt is 60 mm. Determine: a) Bolt stiffness (Note: Convert GPa to MPa. 1 GPA = 1000 MPa):

Answer 1

Answer:

275 MPa

Explanation:

Regardless of what it is holding, the stiffness of a bolt depends on its own material properties and geometry.

The stiffness is:

$k = E * \frac{A}{l}$

I assume this one is made of steel, because regular bolts are steel.

The Young's modulus for steel is E = 210 GPa

The longitude is given. (But note that in a real application you have to consider the length up to the nut.)

The section is (using the nominal diameter of 10 mm)

$A = \frac{\pi * d^2}{4} = \frac{\pi * 0.01^2}{4} = 7.85e-5 m^2$

Then:

$k  = 2.1e11 * \frac{7.85e-5}{0.06} = 275e6 Pa = 275 MPa$