Calculate shear flow q = VQ/I from shear force, first moment of area and moment of inertia in metric or US units, plus shear stress if you add thickness.

Q of the area beyond the point where you want q, taken about the neutral axis.

Second moment of area of the whole cross-section about the neutral axis.

Shear stress (optional)
Web or wall thickness where you want the shear stress. Blank skips it.

Related Calculators

Shear Flow Formula

The following formula is used to calculate the shear flow.

q = (V ร— Q) / I

Variables:

  • q is the shear flow (N/mm)
  • V is the shear force (N)
  • Q is the first moment of area (mm3)
  • I is the second moment of area (area moment of inertia) (mm4)

To calculate the shear flow, multiply the shear force by the first moment of area, then divide by the second moment of area (area moment of inertia).

What is Shear Flow?

Shear flow is a measure of how a shear force is distributed over a cross-section of a beam. It is a critical parameter in the design and analysis of beams and other structural components, as it helps to determine the shear stress distribution within the material. Understanding shear flow is essential for ensuring that structures can withstand the forces they are subjected to without failing.

How to Calculate Shear Flow?

The following steps outline how to calculate the shear flow.

  1. First, determine the shear force (V) in newtons (N).
  2. Next, determine the first moment of area (Q) in millimeters cubed (mm3).
  3. Next, determine the second moment of area (area moment of inertia) (I) in millimeters to the fourth power (mm4).
  4. Next, gather the formula from above = q = (V * Q) / I.
  5. Finally, calculate the shear flow (q) in newtons per millimeter (N/mm).
  6. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem :

Use the following variables as an example problem to test your knowledge.

shear force (V) = 5000 N

first moment of area (Q) = 200 mm3

second moment of area (I) = 10000 mm4