What is "deformation"

Deformation \Def`or*ma"tion\, n. [L. deformatio: cf. F. d['e]formation.]

1. The act of deforming, or state of anything deformed.
   --Bp. Hall.

2. Transformation; change of shape.

mid-15c., "transformation," from Old French deformation and directly from Latin deformationem (nominative deformatio), noun of action from past participle stem of deformare (see deform).

n. 1 The act of deforming, or state of being deformed. 2 A transformation; change of shape.

1. n. a change for the worse [syn: distortion]

2. alteration in the shape or dimensions of an object as a result of the application of stress to it

3. the act of twisting or deforming the shape of something (e.g., yourself) [syn: contortion]

In materials science, deformation refers to any changes in the shape or size of an object due to-

• an applied force (the deformation energy in this case is transferred through work) or
• a change in temperature (the deformation energy in this case is transferred through heat).

The first case can be a result of tensile (pulling) forces, compressive (pushing) forces, shear, bending or torsion (twisting).

In the second case, the most significant factor, which is determined by the temperature, is the mobility of the structural defects such as grain boundaries, point vacancies, line and screw dislocations, stacking faults and twins in both crystalline and non-crystalline solids. The movement or displacement of such mobile defects is thermally activated, and thus limited by the rate of atomic diffusion.

Deformation is often described as strain.

As deformation occurs, internal inter-molecular forces arise that oppose the applied force. If the applied force is not too great these forces may be sufficient to completely resist the applied force and allow the object to assume a new equilibrium state and to return to its original state when the load is removed. A larger applied force may lead to a permanent deformation of the object or even to its structural failure.

In the figure it can be seen that the compressive loading (indicated by the arrow) has caused deformation in the cylinder so that the original shape (dashed lines) has changed (deformed) into one with bulging sides. The sides bulge because the material, although strong enough to not crack or otherwise fail, is not strong enough to support the load without change, thus the material is forced out laterally. Internal forces (in this case at right angles to the deformation) resist the applied load.

The concept of a rigid body can be applied if the deformation is negligible.

Deformation is the rate of change of shape of fluid bodies. Meteorologically, this quantity is very important in the formation of atmospheric fronts, in the explanation of cloud shapes, and in the diffusion of materials and properties.

Deformation can refer to: Deform.

• Deformation (engineering), changes in an object's shape or form due to the application of a force or forces.
  • Deformation (mechanics), such changes considered and analyzed as displacements of continuum bodies.
• Deformation (meteorology), a measure of the rate at which the shapes of clouds and other fluid bodies change.
• Deformation theory, the study of conditions leading to slightly different solutions of mathematical equations, models and problems.

Deformation in continuum mechanics is the transformation of a body from a reference configuration to a current configuration. A configuration is a set containing the positions of all particles of the body.

A deformation may be caused by external loads, body forces (such as gravity or electromagnetic forces), or changes in temperature, moisture content, or chemical reactions, etc.

Strain is a description of deformation in terms of relative displacement of particles in the body that excludes rigid-body motions. Different equivalent choices may be made for the expression of a strain field depending on whether it is defined with respect to the initial or the final configuration of the body and on whether the metric tensor or its dual is considered.

In a continuous body, a deformation field results from a stress field induced by applied forces or is due to changes in the temperature field inside the body. The relation between stresses and induced strains is expressed by constitutive equations, e.g., Hooke's law for linear elastic materials. Deformations which are recovered after the stress field has been removed are called elastic deformations. In this case, the continuum completely recovers its original configuration. On the other hand, irreversible deformations remain even after stresses have been removed. One type of irreversible deformation is plastic deformation, which occurs in material bodies after stresses have attained a certain threshold value known as the elastic limit or yield stress, and are the result of slip, or dislocation mechanisms at the atomic level. Another type of irreversible deformation is viscous deformation, which is the irreversible part of viscoelastic deformation.

In the case of elastic deformations, the response function linking strain to the deforming stress is the compliance tensor of the material.