Shear Flow

Shear flow is used in analysis of beam cross-sections to determine how shear force is distributed across the area of a beam. It is given by:

$$q=\frac{VQ}{I}$$

• $V$ is the shear force acting on the beam, typically at the section where the shear flow is being calculated.
• $Q$ is the first moment of area about the neutral axis for the area above (or below) the point where the shear flow is being calculated. It’s calculated as $Q=\int ydA=\bar{y}A$.
• $I$ is the second moment of area (or moment of inertia) about the neutral axis of the entire cross-section.