Stiffness - Relationship To Elasticity

Relationship To Elasticity

In general, elastic modulus is not the same as stiffness. Elastic modulus is a property of the constituent material; stiffness is a property of a structure. That is, the modulus is an intensive property of the material; stiffness, on the other hand, is an extensive property of the solid body dependent on the material and the shape and boundary conditions. For example, for an element in tension or compression, the axial stiffness is

where

A is the cross-sectional area,
E is the (tensile) elastic modulus (or Young's modulus),
L is the length of the element.

Similarly, the rotational stiffness is

where

"I" is the moment of inertia,
"n" is an integer depending on the boundary condition (=4 for fixed ends)

For the special case of unconstrained uniaxial tension or compression, Young's modulus can be thought of as a measure of the stiffness of a material.

Read more about this topic:  Stiffness

Famous quotes containing the words relationship to, relationship and/or elasticity:

    Women, because of their colonial relationship to men, have to fight for their own independence. This fight for our own independence will lead to the growth and development of the revolutionary movement in this country. Only the independent woman can be truly effective in the larger revolutionary struggle.
    Women’s Liberation Workshop, Students for a Democratic Society, Radical political/social activist organization. “Liberation of Women,” in New Left Notes (July 10, 1967)

    Every man is in a state of conflict, owing to his attempt to reconcile himself and his relationship with life to his conception of harmony. This conflict makes his soul a battlefield, where the forces that wish this reconciliation fight those that do not and reject the alternative solutions they offer. Works of art are attempts to fight out this conflict in the imaginative world.
    Rebecca West (1892–1983)

    A submissive spirit might be patient, a strong understanding would supply resolution, but here was something more; here was that elasticity of mind, that disposition to be comforted, that power of turning readily from evil to good, and of finding employment which carried her out of herself, which was from Nature alone. It was the choicest gift of heaven.
    Jane Austen (1775–1817)