# Theoretical mechanics

Theoretical mechanics . It is the science that deals with the simplest form of the movement of matter , the science that deals with the general laws of mechanical movement and the balance of material bodies or parts of them.

Summary

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• 1 Function
• 2 Division of Mechanics for your study
• 3 Brief historical outline
• 4 Technical Mechanics
• 5 Features
• 6 Technical Mechanics I
• 7 Technical Mechanics II
• 8 The problems to be solved using this science are of two types:
• 9 Technical Mechanics III and IV
• 10 References
• 11 Sources

Function

Theoretical Mechanics studies the real bodies, that is, the material bodies, those existing outside of consciousness and independently of it.

The Mechanics studying how simple and easy to observe movement: mechanical movement.

Mechanical movement is called the change in the position of the material bodies with respect to each other, which happens in the course of time, as well as the variation in the relative position of the particles of the same material body, that is, the formation of the latter. [one]

Depending on the nature of the problems being examined, Mechanics is divided into Statics , Kinematics and Dynamics . In the Statics the notions of the forces and the conditions of the equilibrium of the material bodies subjected to the action of these forces are exposed. Kinematics studies the general geometric properties of the motion of bodies. In Dynamics, the laws of motion of material bodies subjected to the action of forces are examined.

The emergence and development of Mechanics as a science are inseparably related to the history of the development of the productive forces of society and to the level of production and technique at each stage of this development.

Brief historical outline

In ancient times, when production was generally limited to meeting the needs of the construction technique, the science of so-called simple machines (pulley, winch, lever, and inclined plane) and the general science of construction began to develop. body balance ( Static ).

The term “ mechanics ” (from the Greek << mechaniké >> [techne] artifice, machine) was first introduced by the great ancient Greek philosopher Aristotle ( 384 – 322 BC), but his works, which exposed the theory of movement and forces, along with certain correct ideas, contained many incorrect things and were not scientific in nature [2]

The famous mathematician and mechanic of ancient Greece Archimedes ( 287 – 212 BC) should be considered founder of Mechanics, as a precise science, mainly of Statics . Archimedes belongs to a series of the greatest discoveries in Mathematics and Mechanics. In particular, he presented the precise solution to the lever problem and created the center of gravity theory. Archimedes owns the discovery of the law, which bears his name, on the pressure exerted by a liquid on the body immersed in it.

In the Middle Ages the development of Mechanics, like the development of other natural sciences , stopped due to stagnant forms of feudal production.

The flourishing of Mechanics begins from the Renaissance period , from the end of the XV century and beginning of the XVI century , which was the time of the development of commercial capital.

The development of trade led to the development of road building, ship building, navigation, industry, and military art. All this served as a stimulus for a rapid development of science in general and of Mechanics in particular.

Technical Mechanics

It is the discipline that studies the external forces that act on the elements of machines and establishes the logic of the system of actions that must be performed to achieve the calculation and / or design algorithm that corresponds to the criteria of work capacity.

characteristics

This discipline integrates a group of subjects that characterize the basic training of the Bachelor of Education in the Career of Mechanicssince they are taught in all the specialties of Mechanics of Technical and Professional Education and are indispensable instruments for calculating the shape and dimensions of parts and structures based on the conditions of resistance and rigidity and their constructive characteristics, material to be used , requirements for rational exploitation, care, maintenance as well as the observance of safety and environmental regulations. In its thematic conception, a logical sequence is established that includes the main invariants of knowledge associated with Theoretical Mechanics, Strength of Materials and Machine Elements, which requires the Bachelor of Education graduate of this career. This discipline provides a solid trainingBasic, not only with a view to the professional work of the graduate in the subjects it includes, but also for the participation of the Graduate in project work, construction and operation of machine tools, industrial equipment and structures, with their direct participation. The subjects that comprise it are: Technical Mechanics I, II, III and IV.

Technical Mechanics I

It is the subject that studies the statics of solid bodies that takes into account the general properties of forces and equilibrium conditions under the action of applied forces. By equilibrium of a solid body is understood its state of rest with respect to a coordinate system that is considered immobile. The study of the balance of solid bodies is of great importance in Mechanics to ensure the stability of the machines, the material and the dimensions of their elements that are chosen so that the deformations under the loads that act on them are very small.

Technical Mechanics II

It is the subject that studies the resistance of materials from the stresses based on the deformations that occur in the body subjected to external loads which can cause its failure. The difference between Technical Mechanics I and Technical Mechanics II lies in the fact that for this, the properties of deformable bodies are essential, while in general they are not important for the former. Its objective is to determine, from the conditions of resistance and rigidity, the dimensions of the machine elements and structures that correspond (be related) to the applied loads, as well as the assessment and substantiation of the results.

The problems to be solved using this science are of two types:

1. Sizing: it is about finding the most suitable material, shapes and dimensions of a piece, so that it can fulfill its mission: Safely, in perfect technical condition and with adequate expenses.
2. Verification: when the material, shape and dimensions have already been predetermined and it is necessary to know if they are adequate to resist the state of acting stresses

The deformations of the bodies can be elastic, which disappear after the action of forces has been canceled, and plastic or permanent deformations that do not disappear when the loads are removed. In the resistance of materials the following main types of stresses are studied in correspondence with the type of deformation: Tensile – compression, sliding or shearing, torsion and flexion.

Technical Mechanics III and IV

It is a subject oriented to the field of industry and mechanics, mainly in the field of projecting and manufacturing of parts, it applies the physical principles of mechanics, materials science and structural analysis to the analysis of the elements used today, such as machinery for various purposes (hydraulic, transport , manufacturing), as well as various motorized systems, among other applications. Through it alternatives, concepts are presented, procedures for the analysis and design of the elements of machines. Its objective is to project the elements of machines, tools and devices interchangeably, to contribute to the analysis, interpretation and calculation of the reactions and moments caused by external forces, based on the system of science concepts on which it is based, taking as a reference the physical-mechanical principles on which the processes of cutting, forming, as well as the exploitation of machine tools are erectedand means that are used in the different processes. A machine is made up of a series of simpler elements that make it up, being able to define as machine elements all those simpler parts or elements that, when correctly assembled, constitute a complete and working machine. These elements of machines do not necessarily have to be simple, but they must be recognizable as an individual element, outside the machine of which it is part, or the machines of which it can be part.

The development of a very important section of Theoretical Mechanics, Dynamics , arises with “the theory of the heliocentric system of the world” created by the great Polish astronomer Nicolás Copérnico ( 1473 – 1543 ), according to which the center of the universe is the Sun and around its own axes, produced a revolution in the scientific worldview.

The Italian scientist Galileo Galilei ( 1564 – 1642 ) with his investigations related to the clarification of the dependence between the dimensions of the elements of structures and the loads that they can resist, served as a start for the development of a new science, the Resistance of the materials.

The English scientist Isaac Newton (1643-1727), concluding the development of Galileo’s ideas, established the main laws of Classical Mechanics . He introduced the notion of mass and gave an exact formulation to the second law that serves as the foundation for all Dynamics.

In the late nineteenth and early twentieth centuries it was established that the laws of Classical Mechanics could not be applied to the movement of microparticles and bodies moving at speeds close to the speed of light. With the beginning of the 20th century, Relativistic Mechanics was founded on the theory of relativity by Albert Einstein ( 1879 – 1955 ). The theory of relativityWhen establishing normal relationships between space, time, mass and energy, he specified the limits of the use of the laws of Classical Mechanics. However, this essential aspect of the problem did not diminish its importance as a practical method for studying movement that is generally used in the art.

The development of modern technique poses different problems for engineers related to construction calculations (buildings, bridges, canals, dams, etc.), designs, manufacture and operation of different machines, mechanisms, motors and, in particular, objects such as automobiles. , Diesel locomotives, ships, sea and river, planes, rockets, cosmic ships, etc. Currently, Theoretical Mechanics is one of the scientific foundations of modern technical disciplines