#### A 2024-T4 aluminum tube with an outside diameter of 2.50 in. will be used to support a 27-kip load. If the axial normal stress in the member must be limited to 18 ksi, determine the wall thickness required for the tube.

## Solution:

From the definition of normal stress, solve for the minimum area required to support a 27-kip load without exceeding a stress of 18 ksi

The cross-sectional area of the aluminum tube is given by

Set this expression equal to the minimum area and solve for the maximum inside diameter *d *

The outside diameter D, the inside diameter d, and the wall thickness t are related by

Therefore, the minimum wall thickness required for the aluminum tube is