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.
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