Types of deformation

Deformation is the displacement or disruption of bonds between atoms. It appears if external forces influence the subject: temperature, pressure, specific load, magnetic or electric field. The main types of deformation are reversible and irreversible. Reversible deformation, in physics called elastic deformation, means that the breaking of bonds between atoms is insignificant and the integrity structure is not broken. Objects that have this property are called elastic. Irreversible deformation in physics is called plastic deformation and means a serious violation of bonds in atoms and, as a consequence, the integrity of the structure. Items with such properties are called plastic.

Violation of the atomic bond is not always a bad thing. For example, damping (damping vibrations) parts must have plasticity. This is necessary for the transformation of impact energy into deformation energy. There are the following types of deformation of solids: bending, stretching / contraction, torsion and shearing. Depending on the nature of the forces acting on solids, there may be corresponding stresses. These stresses are called by the nature of the force. For example, torsional stress, compression stress, bending stress, etc. Speaking about deformation, often by default, the deformation of solids is implied, because The change in their structure is most pronounced.

In fact, all types of deformation are the result of the influence of the tension created by the acting force. In its pure form, deformation is rare. As a rule, the resulting deformation is the result of a variety of stresses. As a result, they all lead to two basic deformations - stretching / contraction and bending.

Physically deformation is a result that is expressed in a quantitative and qualitative equivalent. Quantitatively, this phenomenon is expressed in a numerical value. Qualitatively - in the nature of manifestation (direction, critical moments, such as destruction, ultimate stress ...). Possible deformation is pre-calculated in the strength calculation when designing any device or mechanism.

As a rule, the loads and the result of deformation are displayed in the form of graphs - stress diagrams. The structure of this graph: the design scheme with the applied loads, types of stresses and types of deformation. The distribution of the loads gives an understanding of the nature of the workload of the device or element, deformation. The results of deformation - stretching, compression, bending, twisting - are measured in units of distance (mm, cm, m) or angular measure (degrees and radians). The main task of the calculation is to determine the ultimate deformations and stresses in order to avoid a malfunctioning - rupture, shear, fracture and so on. Also, the nature of the voltage and the numerical value are important, because There is the concept of fatigue deformation.

Fatigue deformation is the process of changing shape due to long loads. Over time, they develop into serious consequences from uncritical tensions (a constant insignificant violation of interatomic bonds). This concept is called accumulated fatigue and is regulated by such a parameter (from physical properties of the material), as fatigue strength.

In order to take into account the influence that various types of deformation have on the functionality and resource, they carry out full-scale testing of samples of materials. From the experience, all the strength characteristics for each material are obtained, which then become tabular values. In the era of computer technology, this analysis is conducted on powerful PCs. But all the same, the properties of the material can be learned only from full-scale tests. Already laying all the characteristics and properties in the design model, the sturdy gets a graphic model (sometimes in the dynamics of work) of all stresses and deformations.

In the engineering industry, such a calculation has already been incorporated into programs for 3D-design. Those. The designer performs a 3D model of all the elements, each of which is reduced to a node model. Applying loads in a separate module of the program, the designer receives a volumetric picture of the nature of stresses and all kinds of deformation.