by Academician Konstantin FROLOV, Director of Blagonravov Institute of Mechanical Engineering, RAS

The science of machine construction, or mechanical engineering, is rooted deep in our history.

Back in the ancient times people made use of some simple devices activated either by hand or by domesticated cattle.

We know of a whole range of such devices, including tilting surfaces, vedges, levers, windlasses, and pulley blocks designed and used on the basis of practical experience and needs.

The great geographical discoveries of the 15th-16th centuries stimulated urban growth and the development of commerce and production of commodities, in which small workshops were gradually replaced with manufactures. Manual labor was combined with the use of more and more sophisticated technical and mechanical aids whose development involved the knowledge of certain laws and regularities. But theoretical mechanics of that time failed to meet these growing demands, being subject to medieval traditions when logical notions often failed to be put to practical tests.

Within this contest deserving of special attention are the work and achievements of the great mind of the Renaissance period- Leonardo da Vinci (1452-1519). He pioneered studies of the mechanism of birds flight and was very close to developing a flying machine heavier than air. His legacy also includes a range of devices which anticipated the idea of "dismembering" a machine into a set of individual mechanisms. His studies of friction led him to the realization of the impossibility in principle of building a perpetual-motion machine - nearly three hundred years before this was strictly proved and accepted.

Shortly after this was followed by a real boom of mechanics, including the publication in 1501 of studies by other Italian scientists (J. Valla, J. Cardano) with an analysis of mechanical devices developed as far back as the 1 st century A.D. by the Greek scientist Heron. 1575 and 1588 saw the publication by F. Commandino of Heron's treatise Pneumatics. Published in Venice somewhat earlier (1543) was a Latin translation of treatises on mechanics by the Greek mathematician and inventor Archimedes (2877-212 B.C.).

Also published at that time were some independent works describing the experiments and findings of practical mechanics. The Italian engineering scientist of the school of Leonardo da Vinci, A. Romeli (1530-1590), published a treatise describing a whole range of original water-supplying machines and building cranes, and a British engineer C. Schott (1591-1613) described some sophisticated mechanisms of that time - machinery for a brewery, hydraulic and pneumatic devices (forerunners of the gyroscope) and automatic transporter lines.

A number of mechanical units were designed by one of the most gifted Italian scholars of the Renaissance

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period, J. Cardano. And he also engaged in problems of practical mechanics as such. In his studies on gear mechanisms he explained how they should be selected in order to receive the required rpm at the output. And it should be pointed out that typical of the Renaissance scholars is a broad range of interests and universality of pursuits with an engineer being also an architect and a sculptor and a mathematician trying his skills also in medicine and astronomy. It is these enthusiasts of research who laid the foundations of mechanical engineering.

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The impressive progress of science and engineering from the late 16th century and all through the 17th century was hailed as a scientific revolution and its beginning is associated with the publication of the treatise of the Polish scientist Copernicus (1473- 1543) - the founder of modern astronomy. The centuries-old geocentrical system which pronounced the Earth the center of the Universe was replaced with a heliocentrical one which proved that the planets are rotating around the Sun.

This hailed the advent of an epoch of radical revisions of the traditional views and assumptions in all areas of human activity. Engineers and technicians began to rely on practical knowledge gained through the exchange of experience (in the absence of any formal technical education), developing machines for various applications, including lifting devices for construction and mining. The most common of these at that time were wind - and water- mills which were distinguished according to the drive mechanism and their technological applications (crushing and grinding of a primary raw, pressing, drilling, polishing, etc.).

The first attempt to lay the foundation of construction mechanics was the famous treatise of the great Italian physicist and astronomer Galileo Galilei (1564-1642) Lectures and Mathematical Proofs Related to Two New Fields of Science, which formulated the notions of stretching and compression of bodies under load and studied the bending of a console beam resting on two supports. The work also examined the role of the scale factor in terms of ensuring the strength of machines, vessels, buildings and engineering structures when their dimensions are increased. Incidentally, this aspect is taken into account in our present-day modelling theory.

Later still there appeared a work by Robert Hooke (1635-1703), an out-

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standing British encyclopaedist and experimenter, Lecture on the Reducing Power or a Spring Explaining the Force of Elastic Bodies. In his study the scientist established the interdependence between a force stretching a spring and its deformation. In his studies of resilience he formulated a law bearing his name: ut tensia sic via (stretching proportional to force). But his studies were not limited by springs and their stretching. He also studied the bending of a wooden console beam and established that its fibers are compressed on the concave side and stretched on the convex one. The scientist's inventions include the anchor mechanism in watches, pumps and various devices for material testing. His greatest achievement was the formulation of the law of universal gravity which he reported at a meeting of the British Royal Society on May 3, 1666. The concept was proved in a more exact and general form by the British mathematician and natural philosopher Sir Isaac Newton (1643-1727) who formulated his three famous "laws of motion", which laid the foundation of mechanics and gave birth to the theory of machines.

The works of Galilei and Hooke provided the basis for the science of the resilient properties of materials and demonstrated the need of calculating the extension and compression parameters in designing machines and various structures. And it is interesting to note that their studies have not lost their importance to this day and are widely used in mechanical engineering.

A number of scientific discoveries proved to be of great practical importance for the continued progress of science and technology. To give one example, the French mathematician and philosopher B. Pascal (1632-1662) designed and built an original counter. And he is also honored for another outstanding discovery: while working on hydrostatics, he established that pressure exerted on a liquid by external forces is transmitted by it in all directions in an equal measure and does not depend on the volume of the liquid (Pascal law). This law promoted the successful progress of theoretical hydromechanics and found broad applications in the development of hydraulic machines and structures, retaining its practical value up to this day.

The Italian mathematician and physicist E. Torricelli (1608-1647) proved the existence of atmospheric pressure, estimated its value and designed the barometer. His studies of the outflow of liquids from an orifice laid the foundation for the development of hydrodynamics.

In the middle of the 17th century the Dutch scientist Christian Huygens (1629-1695) invented the clock with pendulum, which regulated its movement.

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In the early 18th century the range of mechanical gadgets and technical implements used in Europe embodied as their integral parts levers, tilting surfaces, vedges, windlasses, screws, pulley blocks, etc. and the working tools were the hammer, press, spring, drill, tongs, saws, grinding wheel, plough, sickle, etc. These were activated by a blow, compression, dragging and twisting. Also used were all sorts of transmission mechanisms, like the shaft, gearwheel, pulley, chain, belt and rope and also such elementary pieces of machinery as the loom, self-spinning wheels, different metallurgical and metal processing appliances, winches, etc. At the same time there were also some more sophisticated machines activated by natural energy sources - water- and wind-mills. Developed later were mechanisms providing for continuous and even movement - the flywheel, clocks and automatic devices-the forerunners of the turret-lathe.

A jump in the development of production forces - the so-called industrial revolution (transition from manual to machine production) took place in the British textile industry. Its first signal was the invention by John \\att in 1735 of the spinning loom which did away with the physical effort of man and also his skill. This was followed in the latter years by the development of lathes, milling and planing machines, including those with a mechanical tool holder designed by the Russian engineer Andrei Nartov (1693-1750).

Demand for metal stimulated the development of mining which required

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the participation of engineers and designers for the solution of such technical problems as lifting of ore, pumping of water from great depths, mine ventilation, etc. Machines were constructed for making sheet and profile iron, which called for boosting the capacity of hydraulic presses, better methods of gear design, etc.

The term "hydrodynamics" was first suggested by the Italian mathematician, member of the St. Petersburg Academy of Sciences, Daniil Bernoulli (1654-1705). On the basis of the principle of preservation of forces and on the strength of his numerous experiments he formulated a general theory of equilibrium and movement of liquids and drew up an equation expressing the interdependence of their pressure and velocity.

But the real sign of the times was the steam engine of Thomas Newcoman. In 1711 he developed its first version, which could be called so only approximately: under the pressure of steam, the piston moved upwards with the reverse stroke occurring under atmospheric pressure. The machine operated in a very slow and irregular manner, simply replacing the physical efforts of man and being used only for pumping out water from coal mines.

In 1763 our compatriot Ivan Polzunov invented a steam engine with two cylinders which operated in succession. The machine was installed for the first time in 1765 at a metallurgical plant in the Urals for blowers. To ensure a non-stop operation of his machine, the inventor suggested for the first time the principle of a combined action of several cylinders attached to a common shaft. Later on this basic principle was put to a range of applications, including internal combustion engines which appeared in the 19th century.

This trend was further developed by the British inventor John Watt. In 1768 he identified the dependence of saturated steam pressure from its temperature, and, using his findings, he split the cylinder of his machine into two parts (with one acting as steam condenser). The cylinder was placed into a specially designed steam jacket which considerably boosted the performance of the engine.

Ten years later Watt designed a twin-action steam engine in which the steam was supplied in turns on both sides of the piston. This diagram found many applications and is still in use. Another novelty which is still used today is a centrifugal regulator of a number of revolutions which preserves a steam engine from damaging runaway over-speeding of the piston.

Further improvements of steam engines stimulated the progress of heat physics and the development of the mechanical heat theory. To ensure the successive inputs of steam to the cylinder it was necessary to resolve the then novel problems of kinematics and dynamics of mechanisms and the reciprocal piston movements called for improving the performance of the crank and connecting- rod mechanism.

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The 18th-century industrial revolution broadened considerably the range of scholarly research. There appeared applied sciences and necessity for technical education. Significant landmarks along this path were the works of Mikhail Lomonosov - an outstanding Russian scientist and member of the St. Petersburg Academy of Sciences. In 1747, for example, he published his treatise Reflections on the Causes of Heat and Cold, in which he declared that heat is a form of movement of the tiniest particles of the body. Great interest was aroused by his statements on "the greatest and final degree of cold", at which "particles are fully at rest and their rotary motion stops completely".

In his other work called Reflections on the Solid and Fluid Nature of Bodies (1760), Lomonosov formulated the law of the preservation of energy. And in his book entitled The Initial Foundations of Metallurgy and Mining (1760), he formulated the basics of mining mechanics.

Lomonosov is also widely acclaimed for his works on atmospheric electricity (he discovered the atmosphere of Venus). He tried to create a heavier-than-air flying machine - his "aerodynamic machine" project.

In the meantime, experts in Europe, including Russia, continued to perfect the already available mechanical devices and develop new ones. The Swiss scientist Leonard Eiler (1707-1783), member of the St. Petersburg Academy, substantiated the importance of further development of the theory of machines. He insisted that they should be studied not in a state of rest, as was usually done before, but in motion and in three directions at one and the same time: the first - connected with the motive force, setting the machine into action, the second - transforming this force, and the third - performing the work itself. He also suggested the theory of a turbo-machine, worked on its perfection and provided tangible contributions to hydrodynamics, celestial mechanics, theory of friction and strength of materials. In his treatise On the Strength of Columns Eiler analyzed the lengthwise bending of rods and produced the formula for determining the critical load at which such structures become unstable.

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While examining machines in a state of motion, Eiler embarked on studies of resistance to motion - the forces of friction. Before that the problem had been studied by the Italian scientist Amonton (1663-1705), French scientist A. Paran and Dutch scientist P. Mussenbruck (1692-1761). They clarified the dependence of the latter on the pressure on the contact area of the rubbing bodies. In 1722 Camus (1699-1768) noted that the friction in motion is smaller than the friction at rest. Later on it was established by L. Eiler that friction coefficient approached 1/3, In 1783 the French scientist Charles Coulomb (1736-1806) published his work on the Theory of Simple Machines from the Point of View of Their Components..., which described the laws of slide. On the strength of experiments designed to determine the resistance of water, the French scholar Jean Borda (1733-1799) confirmed the law which had been established by the Dutch scientist Christian Huygens (1629-1695), according to which the resistance of the media to bodies moving within it is approximately proportional to the square of velocity. As for steam engines, they were put to practical uses in water and ground transport in the first quarter of the 19th century The American scientists Robert Fulton and Robert Livingston designed and built in 1803 the first steamer (she was built in North America in 1807). The steamer was powered with a Watt steam engine of 20 HPs, which activated two paddle wheels located on both sides of the vessel.

This was followed by a rather rapid progress of river and ocean steamers. This progress was accentuated by the replacement of wooden hulls with metal ones, growing engine power, introduction of screw propeller and other technical innovations.

1803 saw the birth of the steam engine. The first prototype was designed and built by the British expert R. Travithick (1771-1833) in conjunction with his Italian counterpart Dr. Viviani. But the commonly accepted predecessor of the locomotive of our day and age was a twin-axle railway machine designed by George Stephen-son (1781-1848), the English inventor.

The first public railways were opened in Britain in 1825, in France in 1828, in 1829 in the United States, in Germany in 1835 and in Russia in 1836. All subsequent economic development and effective division of labor on a global scale was inseparably linked with the perfection of mechanical transport in general and railways in particular. By 1850 there were more than 35,000 km of railways on this planet and this number exceeded 1,250,000 km a hundred years later. All this promoted the development of the theoretical foundations of mechanical engineering.

1808 saw the publication by the Paris Polytechnical School of a work by Dr. Lanza and Dr. Betancourt entitled Course of Machine Construction - the

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first textbook on a new science which was later called "the theory of mechanisms".

1815 saw the publication of a work by the Russian scholar P. Chebyshev (from 1853-full member of the St. Petersburg Academy), which was entitled Theory of Mechanisms Known under the Name of Parallelograms. It considered for the first time the analytical synthesis of various mechanisms with the author using mathematical methods of solving the problems involved and thus changing the science of machine mechanics from a descriptive into a calculatory one. In the field of kinematics, the scientist developed a theory of hinge mechanisms. Among the several scores of his new devices of special interest was a propeller mechanism, a gravity chair and a "plantigrade" machine, which has found broad applications in walking robots.

Thus, we see that the objects of research in various fields of mechanics were constantly changing and grew in their complexity. Shortly after engineers started building hydraulic and steam turbines, electric motors, and internal combustion engines, the first of which was suggested in 1860 by the Belgian engineer Etiene Lenoir. In 1833 the German engineer Daimler designed his first four-wheel automobile with an internal combustion engine fitted with a carburettor, a four-speed gearbox and a steering mechanism. In 1884 British engineer Charles Parsons invented the first multistage steam jet turbine, and in 1889 the Swedish scientist Karl Laval (1845-1913) produced its analogue with a supersonic nozzle. This innovation had an important role to play in the progress of turbine construction. Incidentally, our modern steam turbines, capable of operating at super-high pressures and critical temperatures, are the main drive of electrical generators at fuel and also atomic power stations.

In the subsequent years major studies have been conducted in the field of aerohydrodynamics, whose achievements determined to a large extent further progress in promising fields of technology. Of a truly unique importance were the works of the Russian scientist Konstantin Tsiolkovsky in the theory and practice of aviation and aeronautics. It was he who suggested in 1887 the first design of a metal rigid-frame dirigible followed in 1895 by a diagram of an airplane. He also pioneered the idea of an aerodynamic wind tunnel.

The name of Konstantin Tsiolkovsky has gone down in history as that of the enthusiast of interplanetary rocket-propelled flights. He not only dreamed of building a spacecraft for flights to the Moon and other planets, but designed a liquid-fuel rocket for this purpose and suggested the main components of its fuel. He built a model of this rocket and determined the character of its streamlining in an aerodynamic tunnel.

The first operating wind tunnel for carrying out experiments and solving problems of aerodynamics of the aircraft propeller and airfoil was built by

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another Russian expert in the field, Corresponding Member of the St. Petersburg Academy, Nikolai Zhukovsky (1847-1921).

To sum it up, on the verge of the 19th and 20th centuries, the science of mechanical engineering, with all the diversity of the underlying laws, has become a single system of knowledge. Exchanges of methods and ideas between different areas of technology are not a mere coincidence, but the essence of its progress. Ever since its inception machine construction has been increasingly progressing from the studies and explanation of technical achievements to a purposeful theory of developing new complex structures.

* * *

The 20th century has seen an accelerated rate of achievements in physics, chemistry, mathematics, theoretical mechanics, mechanical engineering, thermodynamics, materials technology, and biology, used in the development of fundamentally new machines. Their advent has not only stimulated the progress of both natural and technical sciences, but has also provided the necessary testing technology. For example, the construction of an aerodynamic tunnel fitted out with arrays of high-tech testing gear has made it possible to solve many serious problems of aerodynamics.* The development of new electronic devices has also promoted research in biomechanics, medicine and genetic engineering. The production of space rockets has called for some really unique and pilot-plant studies** and mastering of near-earth space has paved the way for the development of basically new areas of studies of our planet and the Universe as well as for the production of some unheard-of materials in zero gravity.***

With the growth of mass production and saturation of the market (national economy) with large numbers of machines for all sorts of applications we are now facing the problem of a mounting cost of design flaws and technical miscalculations resulting from the lack of necessary scientific data. Technical flaws and breakdowns have been the cause of major tragedies and disasters and this menace is still with us today.

The scale of our scientific and technological progress is especially impressive when we compare the "age of steam" with the "age of electricity" - a common epithet for the past century before the split of the atom and the beginning of space studies. The good old steam engine which activated a couple of lathes with the help of belt drives and shafts has been replaced with powerful generating stations which supply electricity over practically unlimited distances to millions of industrial users, railways and urban transport and residential areas. A key role in all of these achievements clearly belongs to mechanical engineering. It has developed into a basic area of science in its own right whose importance continues to grow in the new century as the theoretical base for making the machines of the future. A pride of place in this field belongs to people like academicians Yevgeny Chudakov (1890-1953) and Anatoly Blagonravov (1894-1975), the first directors of our Institute who laid the foundations of the leading schools of

*See: T. Fomina, "Aircraft Capital of Russia", Science in Russia, No. 6, 2000. - Ed .

** See: V. Senkevich, "Russian Space Research at the Turn of Centuries", Science in Russia, No. 1, 2001. - Ed .

*** See: M. Milvidsky et al., "Monocrystals of 'Space Quality'", Science in Russia, No. 1, 1999. - Ed .

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research. Important contributions to the development of mechanical engineering were also made by Academicians Ivan Artobolevsky (1905-1977), Nikolai Bruyevich (1896-1987), Vladimir Dikushin (1902-1979) and Yuri Rabotnov (1914-1985) to mention but a few.

Our Institute researchers also deserve much credit for the development of the theory of machines and mechanisms, their friction and wear, strength of components and the processing of metals by cutting. The studies of Yevgeny Chudakov on the stability and controllability of cars have received international recognition.

The aforesaid is but a short list of pioneering research accomplished by our Institute staff who have provided a major contribution to the progress of mechanical engineering. This also covers systems of digital-program control of machine-tools, motors and mechanisms of walking machines, high-performance vibration and ultrasonic technological equipment of the resonance type and many more things.

The 20th century has been inscribed in history as an age of nuclear power stations, space research, television and computers as integral parts of the scientific and technological progress. But have we become happier as a result of these grandiose achievements of the human brain, have we enriched the eternal spiritual legacy of mankind and have we come closer to the great ethical goals and ideals? The paradox of the situation consists in the fact that this era of the greatest scientific and technical achievements passes on to the new century some of their tragic "side effects" such as the struggle for survival in the conditions of technogenic catastrophes,* ecological damage, depletion of natural resources and the unpredictable consequences of using atomic energy for other than peaceful purposes. And that means that a simple extrapolation of tendencies formed in the recent past is not enough for human survival and the growth of our spiritual legacy in the future.

What we need is a new concept of scientific and technological progress which should be based upon an analysis of the needs and possibilities of ensuring the viability and a moral revival of the human race. The present-day strategy of scientific progress should give priority to research which is of particular importance for the very prospect of the survival of the international community, its sustained and safe development. And modern mechanical engineering assumes the role of a theoretical base for the development of the mechanical tools of the future, materials and high technologies, of ensuring technogenic safety and favorable conditions of human existence on Earth.

* See: K. Frolov et al., "Engineering Systems", Science in Russia, No. 3, 1994. - Ed.

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