Shear force is a force acting on a substance in a direction perpendicular to the extent of the substance, acting in the direction of the planar cross-section of the object.
Shear force is the sum of the effects of shear stress on a surface, usually resulting in shear strain. Bending moment and shear force calculations are required when designing any structural member.
Shear force is an internal force in any material, usually caused by any external force acting normal to the material or having a component acting tangential to the material. Shear forces are misaligned forces that push one part of the body in one direction while pushing another part of the body in the opposite direction. When these forces are aligned with each other, they are called compressive forces.
For example, apply a force of 10 Newtons (N) to the edge of a beam. This is an external force. Since the beam is a rigid structure, forces are transmitted throughout the interior of the beam. This internal force is called shear force. The shear force between one end and the other is usually plotted on a shear diagram. In contrast to tensile and compressive stress and strain, shear forces act on areas consistent with the force.
Shear and Bending Moment Diagrams are analytical tools used in conjunction with Structural Analysis to help perform structural design by determining the shear and bending moment values at a given point on an element.
Using these charts, the type and size of members of a given material can be easily determined. Lateral loads also induce shear forces, causing shear deformation of the material and increasing the lateral deflection of the member.