Hooke's law of elasticity states that the amount by which a body is deformed (the strain) is linearly related to the force causing the deformation (the stress). Materials for which Hooke's law is a useful approximation are known as linear-elastic or "Hookean" materials.
For those systems:
F=-kx
wherex is the elongation,
F is the restoring force
k is the spring constant.
Hooke's law only holds for some materials under certain loading conditions. Materials such as rubber, for which Hooke's law is never valid, are known as "non-hookean".
Young's Modulus (Y) is a measure of the stiffness of a material. It is defined as the ratio, for small strains, of the rate of change of stress with strain.
For many materials, Young's modulus is a constant over a range of strains. Such linear materials are said to obey Hooke's law. Then Young's modulus can be used to calculate the force it exerts under a specific strain.
F=Y A0 ΔL/L0
Where F is the force exerted by the material when strained by ΔL and A0 is the original cross-sectional area through which the force is applied. As x = ΔL then in Hooke's law, F = kx, we have
k=Y A0/L0
Wed, 2010-09-01 17:33
- Login or register to post comments
»