Can Anyone Explain this to me?

Question

Stress
Strain and
Elasticity
[physics]

Answer 1

Stress is the internal distribution of force per unit area that balances and reacts to external loads applied to a body. It is a second-order tensor with nine dimensions, but can be fully described with six dimensions due to symmetry in the absence of body moments. Stress is often broken down into its shear and normal components as these have unique physical significance.

Stress can be applied to solids, liquids and gases. Static fluids support normal stress (hydrostatic pressure) but will flow under shear stress. Moving viscous fluids can support shear stress (dynamic pressure). Solids can support both shear and normal stress, with ductile materials failing under shear and brittle materials failing under normal stress. All materials have temperature dependent variations in stress related properties, and non-newtonian materials have rate-dependent variations.
In any branch of science dealing with materials and their behaviour, strain is the geometrical expression of deformation caused by the action of stress on a physical body. Strain is calculated by first assuming a change between two body states: the beginning state and the final state. Then the difference in placement of two points in this body in those two states expresses the numerical value of strain. Strain therefore expresses itself as a change in size and/or shape.

If strain is equal over all parts of a body, it is referred to as homogeneous strain; otherwise, it is inhomogeneous strain. In its most general form, the strain is a symmetric tensor.

In the case of geological action of the earth, if the release of stress through strain in rocks is sufficiently large, earthquakes may occur.
Under small stresses many solids' strains are roughly proportional to the stresses they are undergoing. The constant of proportionality (sometimes known as the elasticity), is given by the reciprocal of Young's modulus of elasticity, which is a measure of stiffness. Thus, elasticity is typically modeled using a linear relationship between stresses and strain (see "Linear elasticity"). The classic theoretical example of linear elasticity is the perfect spring, whose behavior is described by Hooke's law. Linear elasticity, however, is an approximation; real materials exhibit some degree of non-linear behavior. Whether working with linear or non-linear models, the relationship between stress and strain is often described using tensor methods and the elasticity tensor.

Answer 2

O Sikander, O Sikander O Sikander, Jhaank Le Jhaank Le Apne Dil Ke Andar from Corporate

Answer 3

stress is mechanical perturbation(i.e.,force/area)
strain is amount of change produced due to the perturbation(fractional length change,for example)
elasticity is measure of susceptibility of any matter to change under a given perturbation(expressed as young's modulus=stress/strain)

Answer 4

stress = force /area
strain= l/del l