SHEAR STRENGTH

'Shear strength' in engineering is a term used to describe the strength of a material or component against the type of yield or structural failure where the material or component fails in shear.
In structural and mechanical engineering the shear strength of a component is important for designing the dimensions and materials to be used for the manufacture/construction of the component. For example, beams, plates, bolts etc. In a reinforced concrete beam, the main purpose of stirrups is to increase the shear strength.
''σ₁'' = Major Principal Stress;
''σ₃'' = Minor Principal Stress;
& Shear stress $au$ = ''(σ₁ - σ₃)/2''
In general: ductile materials fail in shear (ex. aluminum), whereas brittle materials (ex. cast iron) fail in tension. See tensile strength.
To calculate:
Given failing force and area, example-bolt shear strength:
$au$ = ''F/A'' = ''(F)/(π
★ r²_bolt)'' = ''(4
★ F)/(π
★ d²_bolt)''