solid mechanics Solid mechanics (also known as mechanics of solids) is the branch of continuum mechanics that studies the behavior of solid materials, especially their motion and deformation (mechanics), deformation under the action of forces, temperature chang ...

, shearing forces are unaligned

force In physics, a force is an influence that can cause an Physical object, object to change its velocity unless counterbalanced by other forces. In mechanics, force makes ideas like 'pushing' or 'pulling' mathematically precise. Because the Magnitu ...

s acting on one part of a body in a specific direction, and another part of the body in the opposite direction. When the forces are

collinear In geometry, collinearity of a set of Point (geometry), points is the property of their lying on a single Line (geometry), line. A set of points with this property is said to be collinear (sometimes spelled as colinear). In greater generality, t ...

(aligned with each other), they are called '' tension forces'' or ''

compression forces In mechanics, compression is the application of balanced inward ("pushing") forces to different points on a material or Structural system, structure, that is, forces with no Net force, net sum or torque directed so as to reduce its size in one ...

''. Shear force can also be defined in terms of planes: "If a plane is passed through a body, a force acting along this plane is called a ''shear force'' or ''shearing force''."

Force required to shear steel

This section calculates the force required to cut a piece of material with a shearing action. The relevant information is the area of the material being sheared, i.e. the area across which the shearing action takes place, and the shear strength of the material. A round bar of steel is used as an example. The shear strength is calculated from the tensile strength using a factor which relates the two strengths. In this case 0.6 applies to the example steel, known as EN8 bright, although it can vary from 0.58 to 0.62 depending on application. EN8 bright has a tensile strength of 800MPa and mild steel, for comparison, has a tensile strength of 400MPa. To calculate the force to shear a 25 mm diameter bar of EN8 bright steel; : area of the bar in mm² = (12.5²)(π) ≈ 490.8mm² : 0.8kN/mm² × 490.8mm² = 392.64kN ≈ 40tonne-force : 40tonne-force × 0.6 (to change force from tensile to shear) = 24tonne-force When working with a

rivet A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylinder (geometry), cylindrical shaft with a head on one end. The end opposite the head is called the ''tail''. On installation, the deformed e ...

ed or tensioned

bolted joint A bolted joint is one of the most common elements in construction and machine design. It consists of a male threaded fastener (e. g., a Bolt (fastener), bolt) that captures and joins other parts, secured with a matching female screw thread. Ther ...

, the strength comes from friction between the materials bolted together. Bolts are correctly torqued to maintain the friction. The shear force only becomes relevant when the bolts are not torqued. A bolt with property class 12.9 has a tensile strength of 1200MPa (1MPa = 1N/mm²) or 1.2kN/mm² and the yield strength is 0.90 times tensile strength, 1080MPa in this case. A bolt with property class 4.6 has a tensile strength of 400MPa (1MPa = 1N/mm²) or 0.4 kN/mm² and yield strength is 0.60 times tensile strength, 240MPa in this case.

References

{{Authority control Force Civil engineering

Force required to shear steel

See also

References