Deformation: shear, stretching, compression, torsion, bending. Examples of deformation

Deformation of shear, torsion, bending is a change in the volume and shape of the body when an additional load is applied to it. In this case, the distances between molecules or atoms change, leading to the appearance of elastic forces. Let us consider the main types of deformations and their characteristics.

Compression and stretching

Strain deformation is related to the relative or absolute elongation of the body. An example is a homogeneous rod, which is fixed at one end. When applying force along the axis acting in the opposite direction, stretching of the rod is observed.

The force applied to the fixed end of the rod leads to compression of the body. In the process of compression or stretching, the cross-sectional area of the body changes.

Strain deformation is a change in the state of an object, accompanied by a displacement of its layers. This type can be analyzed on the model of a solid body consisting of parallel plates, which are connected together by springs. Due to the horizontal force, the plates are shifted to some angle, the volume of the body remains unchanged. In the case of elastic deformations , a directly proportional relationship is established between the force applied to the body and the shear angle.

Bending strain

Let us consider examples of deformation of a given kind. In the case of bending, the convex part of the body undergoes some stretching, and the concave fragment contracts. Inside the body subjected to this variant of deformation, there is a layer that does not experience either compression or stretching. It is usually called the neutral section of the deformed body. Near it, you can reduce the area of the body.

In the technique, examples of deformation of this type are used to save materials, as well as to reduce the weight of the structures being erected. Continuous bars and rods are replaced by pipes, rails, I-beams.

Torsional strain

This longitudinal deformation is an inhomogeneous shift. It occurs when forces acting parallel or opposite to the rod, which has one end fixed. Most often, complex deformations are subjected to various parts and mechanisms used in structures and machines. But due to the combination of several variants of deformations, it is much easier to calculate their properties.

By the way, in the process of significant evolution, the bones of birds and animals adopted a tubular version of the structure. This change contributed to maximum hardening of the skeleton at a certain body weight.

Deformations on the example of the human body

The human body undergoes serious mechanical stresses from its own efforts and weight, appearing as far as physical activity. In general, deformation (shift) is characteristic for the human body:

• Compression is experienced by the spine, the covers of the feet, and the lower limbs.
• Stretch the ligaments, upper limbs, muscles, tendons.
• Bending is typical for limbs, pelvic bones, vertebrae.
• Torsion is exposed during the turn of the neck, when it is rotated, the hands are tested.

But if you exceed the marginal voltage, you may break, for example, the bones of the shoulder, hip. In the ligaments, the tissues are joined so elastically that they can be stretched twice. By the way, the shear deformation explains the danger of women moving on high heels. The weight of the body will be transferred to the fingers, which will increase the load on the bones by half.

According to the results of medical examinations conducted in schools, out of ten children only one can be considered healthy. How are deformities related to children's health? Shift, torsion, compression are the main causes of the violation of posture in children and adolescents.

Strength and deformation

Despite the diversity of the living and non-living world, the creation of numerous material objects by man, all objects and living beings have a common property - strength. Under it is customary to understand the ability of the material to persist for a long time period without visible damage. There is strength of structures, molecules, structures. This characteristic is appropriate for blood vessels, human bones, a brick column, glass, water. Shear deformation is a variant of testing the structure for strength.

The use of different types of deformation by man has deep historical roots. It all started with the desire to connect a stick and a sharp tip between them to hunt the ancient animals. Already in those distant times a person was interested in deformation. Shift, contraction, stretching, bending helped him to create dwellings, tools, to prepare food. As technology advances, mankind has managed to use various types of deformations so that they can bring significant benefits.

Hooke's Law

Mathematical calculations required in construction and engineering allowed the use of Hooke's law for shear deformation. The formula showed a direct relationship between the force applied to the body and its elongation (compression). Hooke used the coefficient of rigidity, showing the relationship between the material and the possibility of its deformation.

With the development and improvement of technical means, apparatus and instruments, the development of resistance theory, serious studies of plasticity and elasticity have been carried out. The results of the fundamental experiments were applied in construction equipment, theory of structures, theoretical mechanics.

Due to the complex approach to the problems associated with various types of deformation, it was possible to develop the construction industry, to prevent the correct posture in the younger generation of the country.

Conclusion

The deformations considered in the course of school physics influence the processes taking place in the living world. In the organisms of man and animals, torsion, bending, stretching, and contraction are constantly occurring. And in order to carry out timely and full-fledged prevention of problems associated with posture or overweight, physicians use the dependencies discovered by physicists in basic research.

For example, before calculating the lower limbs, a detailed calculation of the maximum load on which it should be calculated is performed. Prostheses are selected for each person individually, since it is important to take into account the weight, height and mobility of the latter. When violations of posture apply special corrective belts, based on the use of shear deformation. Modern rehabilitation medicine could not exist without the use of physical laws and phenomena, including without taking into account the patterns of various types of deformations.