Shear stress
• As mentioned previously, shear stress is the type of stress that features one plane sliding over another.
• Also mentioned before is that the effective area in calculating shear stress is PARALLEL to the external force.
• This makes the formula to calculate shear stress:
(1)
\begin{align} \sigma_s = \frac{L}{A_s} \end{align}

Where:

• $\sigma_s$ is the shear stress (Pa)
• $L$ is the external force/Load (N)
• $A_s$ is the shear area ($m^2$) • Note that there are about 3 different ways shear stress can take place:
• Single shear stress
• This is the most simple of the shear stresses.
• For a situation like (1), the shear force would be acting on the cross sectional area of the bolt(blue).
• Thus, the shear area would be the bolt's CSA. Then simply apply the formula to calculate the shear stress.
• Double shear stress
• This is when a situation like (2) occurs.
• The shear force would still be acting on the CSA of the bolt, but it's on 2 different planes.
• Thus the shear area would be DOUBLE the bolt's CSA.
• Punching shear stress
• This is a special case where the where the operation punches a hole in a plate
• In a case like (3), the shear stress in the plate acts on the hole's "edge" (blue)
• Thus, the shear area would be the perimeter of the hole multiplied by the thickness of the material.
page revision: 1, last edited: 12 Jan 2011 09:08