The figure shows the free body diagram of the aluminum bar sandwiched between copper bars. The free body diagram cuts through the copper bar on the top and the pin on the left. The force on the copper bar is F subscript 1 directed rightwards and the shear force on the pin on the left is F subscript pin directed leftwards.

To determine the shear stress produced in the 11-mm diameter pin, first draw a FBD that cuts through the pin. By inspection, the force in the pin must equal the internal force F1 in the copper bar.

For this FBD, the pin is in single shear; therefore, the area subjected to shear stress is simply the cross-sectional area of the pin (95.03 mm2).

The shear stress can be calculated as: