| shear stress A form of stress that subjects an object to which force is applied to skew, tending to cause shear strain. For example, shear stress on a block of wood would arise by fixing one end and applying force to this other; this would tend to change the block's shape from a rectangle to a parallelogram. See also strain. |
force tending to cause deformation of a material by slippage along a plane or planes parallel to the imposed stress. The resultant shear is of great importance in nature, being intimately related to the downslope movement of earth materials and to earthquakes. Shear stress may occur in solids or liquids; in the latter it is related to fluid viscosity.