Mechanical stress of bodies - definition and formula, properties of solids

With the interaction of solids with various environmental factors, changes can occur - both internal and external. One example is the mechanical stress that appears in the bowels of the body. It determines the degree of possible changes in the damage.

Basic concepts in physics

Mechanical stress is a measure of the internal forces of an object that arises under the influence of various factors. For example, when a deformation occurs, during which external forces try to change the mutual arrangement of particles, while internal forces prevent this process, limiting it to some specific value. Thus, we can say that mechanical stress is a direct consequence of the load on the body.

There are two main types of mechanical stress:

1. Normal - applied to a single area of the section along the normal to it.
2. The tangent is applied to the area of the section along the tangent to it.

The set of these stresses acting at one point is called the stress state at this point.

Measured in pascal (Pa) mechanical stress: the calculation formula is presented below

Q = F / S,

Where Q is the mechanical stress (Pa), F is the force that appears inside the body under deformation (H), S is the area (mm).

Properties of solids

Solid bodies, like all the others, consist of atoms, but they have a very strong structure, which practically does not undergo deformation; Volume and shape remain constant. Such objects have a number of unique properties that can be divided into two large groups:

1. Physical.
2. Chemical.

The physical can include the following:

1. Mechanical - they study them with the help of an appropriate impact on the body. These properties include elasticity, brittleness, strength, i.e. All that is related to the ability to resist deformation caused by external factors.
2. Thermal - study the effect of different temperatures on the object. These include expansion with heating, thermal conductivity, heat capacity.
3. Electrical - these properties are associated with the movement of electrons within the body and their ability to assemble into an ordered flow under the influence of external factors. An example is electrical conductivity.
4. Optical - are studied using light streams. These properties include light reflection, light absorption , diffraction.
5. Magnetic - are determined by the presence of magnetic moments in the components of a solid. For them, as well as for electric ones, there are negatively charged particles due to their structure and a certain movement.

Chemical properties include everything related to reaction to the action of the relevant substances and processes occurring in this process. An example is oxidation, decomposition. The structure of the crystal lattice also refers to these properties of the object.

A small group of physicochemical properties can also be distinguished . It includes those of them that manifest themselves in both mechanical and chemical effects. An example is combustion, during which changes occur in the two above-mentioned characteristics.