Elastic deformation. Theory of elasticity
The impact of external forces on some bodyleads to a variety of consequences. The object of impact can get acceleration and start moving. In the process of motion or in a state of rest within it, certain changes may occur that have been called "deformation".
The very word "deformation" comes from the Latindeformatio, which means "distortion". By this notion, it is customary to mean the process by which the mutual position of the body particles changes, that is, the particles themselves move relative to each other. Deformation as a result of a change in the distance of the interatomic distances leads to a rearrangement of the blocks of atoms. Often, it is associated with a change in the values of the interatomic forces. The measure of strain is mechanical stress. Due to deformation, the body can receive traces of impact that remain, or may be restored, acquiring the previous state that it had before external influence.
If the body regains its form, then thisThe form of the deformation is called elastic. Elastic deformation, as the specialized literature says, is a deformation that disappears after the action of external forces ceases. The body acquires the former form, its dimensions are restored.
This definition is taken from the physics section,studying the elastic deformation, which is called the theory of elasticity. Elastic deformation has a distinctive property: its magnitude does not depend on the prehistory, mechanical stresses are its primary cause. In other words, it is completely determined and depends on the mechanical stresses. In most substances this dependence with high accuracy is considered as direct proportionality. Elastic deformation strictly obeys a certain physical law, it is still known as Hooke's law. The maximum stress at which the law of elastic deformation remains valid is called the proportionality limit.
Some materials (rubbers, metals) possessan exceptional property to withstand significant indices of elastic deformation, for other substances (compacts, ceramics), there can be no very slight deformation of the elastic. The maximum mechanical stress, the deformation at which still falls under the definition, is usually called the yield point. Having overcome this value, the elastic deformation grows into a plastic deformation.
Due to deformation, which has the properties of elastic andperiodically repeating, there is a phenomenon called elastic vibrations. When the elastic oscillations begin to propagate, this phenomenon is called elastic waves.
Considering elastic deformation, it is not necessaryforget that the elastically deformed body has a certain amount of energy. The energy of elastic deformation refers to the form of the energies of the position or, in other words, is potential. An elastically deformed body is able to perform a certain job, restoring its previous state. In the ideal case, the magnitude of this work is equal to the amount of work spent on the process of deformation.
Due to its properties, elastic deformationis widespread in the practical life of man. Of great importance in various mechanical devices is the use of parts whose functioning directly depends on their ability to be deformed elastically. Some of them accumulate energy, for example, a spring in a mechanical clock, others soften the effect of external forces on the device (shock absorbers, springs).
In the process of creating various mechanisms,it is noticed that the property of elastically deforming is affected not only by what material is made of this or that part, but also by the processing process that it took.