Stiffness ‘K’ is defined as Force/length. Physical
interpretation-Stiffness is equal to force required to produce unit
displacement. Stiffness depends on geometry as well as material properties.
Consider 3 rods of exactly same geometrical dimensions-Cast
iron, Mild Steel, Aluminium. If we measure force required to produce 1 mm
displacement then Cast iron would require maximum followed by steel and
Aluminium respectively KCI>KMS>K Al
Now consider 3 different c/s rods of same material. Again
force required to produce unit deformation will be different. Hence stiffness
depends on geometry as well as material.
