How to Calculate Slip Plane

Look at the shape of the item you're trying to find the slip plane for. Identify the tensile axis. The tensile axis runs vertically down the center of the crystal structure.

Locate the pole of the triangular family of slip planes in the particular system you're studying. The pole will be the center of the plane from the tensile axis, and has even distribution on all sides of the plane from the pole.

Draw a line out from the pole in the slip plane to the edge of the crystal that's opposite from the slip direction. Label this line "Slip Plane N" for normal. Use a protractor to find the angles between the slip plane N and the tensile axis. Write this number down. Calculate the angle of the tensile axis and the slip direction. Write this number down. Both values should be written in terms of angle degrees.

Use a calculator to multiply the first angle by the second angle. Multiply the answer by the amount of applied stress to calculate the shear stress of the crystal. The shear stress equals the area of the slip plane divided by the shear force. To calculate the area of the slip plane, you must also have the value of the shear force, which will be given to you in the problem. The equation, then, looks like: shear stress = shear force/area of slip plane.