The impact of external forces on any body leads to a variety of consequences. The object of influence can get acceleration and start moving. In the process of movement or at rest, certain changes can occur inside it, which are called "deformation".
The word “deformation” itself comes from the Latin deformatio, which means “distortion”. By this concept it is customary to mean a process, as a result of which a change in the relative position of the particles of the body occurs, that is, the particles themselves move relative to each other. Deformation as a result of a change in the distance of interatomic distances leads to a rearrangement of atomic blocks. Often it is associated with a change in the magnitude of interatomic forces. A measure of deformation is mechanical stress. Due to deformation, the body can receive traces of exposure that remain, or it can recover, acquiring the previous state that it had before the external influence.
If the body restores its shape, then this type of deformation is called elastic. Elastic deformation, as specialized literature says, is a deformation that disappears after the action of external forces ceases. The body takes its previous shape, its size is restored.
This definition is taken from the section of physics studying elastic deformations, which is called the theory of elasticity. Elastic deformation has a distinctive property: its value does not depend on the background, mechanical stresses are its primary cause. In other words, it is completely determined and depends on mechanical stresses. In most substances, this dependence with high accuracy is considered direct proportionality. Elastic deformation strictly obeys a certain physical law; it is also known as Hooke's law. The maximum stress at which the law of elastic deformation preserves justice is called the limit of proportionality.
Some materials (rubbers, metals) have the exceptional ability to withstand significant indicators of elastic deformation, for other substances (pressed materials, ceramics) a very slight elastic deformation cannot be. The maximum mechanical stress, deformation at which still falls within the definition, is usually called the yield strength. Overcoming this value, elastic deformation develops into plastic.
Due to the deformation, which has the properties of elastic and periodically repeating, there is a phenomenon called elastic oscillations. When elastic vibrations begin to propagate, this phenomenon is called elastic waves.
When considering elastic deformation, one should not forget that an elastically deformed body has a certain energy reserve . The energy of elastic deformation refers to the form of position energies or, in other words, is potential. An elastically deformed body is able to perform a certain work, restoring its previous state. In the ideal case, the magnitude of this work is equal to the magnitude of the work spent on the deformation process.
Due to its properties, elastic deformation is widespread in the practical life of man. Of great importance in a variety of mechanical devices is the use of parts, the functioning of which directly depends on their ability to elastically deform. Some of them accumulate energy, for example, a winding spring in a mechanical watch, while others soften the effect of external forces on the device (shock absorbers, springs).
In the process of creating various mechanisms, it was noticed that the property of elastic deformation is affected not only by what material a particular part is made of, but also by what processing process it went through.