Applied mechanics

The Engineering Mechanics is a branch of Technical Physics. Your scientific basis is the classical mechanics, which in turn is a branch of physics. The tasks of engineering mechanics is to provide the theoretical calculation method, for example, materials science, mechanical engineering and structural engineering. The actual design, selection of materials and the like is then carried out by these application-oriented disciplines in which the Engineering Mechanics is an auxiliary science.

Objects of engineering mechanics are:

• The laws of classical mechanics
• Mathematical models of the mechanical correlations physical body,
• Specific and efficient methods of computational analysis of mechanical systems.

Branches of engineering mechanics

The classification of engineering mechanics is not uniform everywhere. In general can be regarded as branches of engineering mechanics:

• Kinematic: The movement of the body, excluding the forces
• Dynamics: The mechanics of bodies under the action of force Statics: The mechanics of the body at rest Theory of frameworks as well as the surface and spatial structures

• Friction theory as a special case of the kinetics
• Vibration theory: The specialty area of ​​the kinetics of the vibration analysis of bodies
• Mechanism of shock: A special area of the kinetics of short -term force effects in bodies

• Elasticity theory: the generalization of Hooke's law
• Plasticity theory: studies on the laws in non- Hooke area

• Plastic hinge theory: the expansion of the strength of materials in the plastic range
• Notch stress theory: A special area of strength of materials and limit range of engineering mechanics to materials science

Specific areas:

• Stability theory: The study of dynamic motion stability or stability of stressed bodies against breakage by the second-order theory (such as Knickungsvorgänge )
• Rotor dynamics and engine dynamics: Studies on the interaction between dynamic forces and motion variables within machines where it is necessary to submit rotating assemblies of a technically controllable rotary motion
• Soil Mechanics: Describes deformations and stresses in continua (eg half-spaces ) with constitutive equations that approximate the real constitutive laws of soils
• Biomechanics: Mechanical analysis of living structures
• Viscoelasticity: A special area of continuum mechanics that deals with the study of viscoelastic media
• Contact Mechanics: Studies on the static and dynamic ( wallowing or rolling ) contact of bodies, in particular the creation of models for surface pressure in the contact zone.

Essentially, you can narrow the field of engineering mechanics to the determination of stresses and deformations of elastic bodies and the motion of solid bodies. The rest of the body as an important limiting case of the motion is determined in engineering mechanics with the help of statics. In addition to the classical engineering mechanics, which aims at a closed mathematical description in differential equations, the development of numerical methods is becoming increasingly important. Thermodynamics (eg: heat transport or cycle processes in engines and turbines) and fluid mechanics (hydraulics, fluid mechanics) are usually not as part of the technical mechanics, but as independent branches of engineering.

More special branches of engineering mechanics calculations are the location and control of the satellites and the ballistics.

History of Engineering Mechanics

For most people it is given from our own intuition to solve elementary problems of statics and dynamics, without being themselves aware of the actual background. As a very typical example of this assumption is valid in the static of the carrier, you can make fairly accurate information on its capacity already from the mere perception out.

Formal Engineering Mechanics has been operated by Archimedes, but analytically meaningful conclusions only from the time the first half of the 17th century have survived. The former mathematicians were inspired by the vivid laws of mechanics to their new knowledge, at the same time they discovered a number of new insights and mathematical principles of engineering mechanics. In the following centuries, their theories were introduced in the technique and made it workable in practice, while further theoretical findings followed. At the same time the practitioner calculated the ballistic flight of a cannonball and on the other hand studied the effect of this cannon ball on the walls of a fortress by a clever choice of the external dimensions of the fortress to be minimized.

The Greek Archimedes was the first mathematician who thoroughly dealt with mechanical problems. He discovered the laws of hydrostatics, as they are still valid today. Simon Stevin designed the parallelogram of forces by the eponymous Stevinsches thought experiment. Johannes Kepler described the movements of the planets and moons with mathematical tools. The discovered during Kepler's laws are still used for path calculation of artificial satellites and space probes.

Galileo Galilei is in the early modern period to the merit of having made ​​the nascent science of engineering mechanics to a formal mathematical basis. The second day of his Discourses deals mainly with the discussion of resistance problems. In the same spirit seemed Isaac Newton, based on mechanical observations wrote the history of science with the invention of calculus. Christiaan Huygens already delivered practical results of his research in the form of the pendulum clock and more accurate knowledge of astronomy. The members of the Bernoulli family prepared in the 18th century as well as other theoretical findings set the stage for an even more valid today, engineering mechanics, which forms the basis for many disciplines of engineering. Leonhard Euler named the theories of buckling, the beams bend and understanding of modern turbines. In the same period, Charles Augustin de Coulomb established the fundamentals of tribology, which provided an improved understanding of the functioning of the same invented machines. One also more adapted to the needs of practitioners Engineering Mechanics developed in the 19th century Karl Culmann, August Ritter, Giuseppe Cremona and Carlo Alberto Castigliano. Their solutions -based mechanical problems due to lack of powerful computing machines mainly to exact geometric drawings. Another important name from the time of the late 19th and early 20th century in the field of engineering mechanics is Christian Otto Mohr, from the origin of the studies on the Mohr's circle and taught at the same time at the Technical University of Dresden as Ludwig Burmester, the inventor of the template of the same name.

In the 20th century the aerodynamics developed for the needs of the aerospace industry by Ludwig Prandtl and Theodore von Kármán. At the same time John Argyris and other mathematicians developed the finite element method. The iterative method is used in the thirties to flower -developing building construction for the static calculation, as published by Gaspar Kani or Hardy Cross. All these methods use the numerics as an essential approach.

Many of the entities referred to in other areas deserving of high praise (eg in the hydro- mechanical, optical, electrical, relativity and quantum mechanics). On the other hand, the Engineering Mechanics namesake was for a whole class of mathematical objects: The tensors were named after the stress tensor, which was introduced in the context of the theory of elasticity.