Georg Wilhelm Christian Caspar Duffing (born April 11, 1861 in Waldshut; died April 5, 1944 in

Schwedt/Oder Schwedt (or Schwedt/Oder; ) is a town in Brandenburg, in northeastern Germany. With the official status of a '' Große kreisangehörige Stadt'' (major district town), it is the largest town of the Uckermark district, located near the river Oder ...

) was a

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ger ...

engineer Engineers, as practitioners of engineering, are professionals who invent, design, analyze, build and test machines, complex systems, structures, gadgets and materials to fulfill functional objectives and requirements while considering the l ...

and

inventor An invention is a unique or novel device, method, composition, idea or process. An invention may be an improvement upon a machine, product, or process for increasing efficiency or lowering cost. It may also be an entirely new concept. If an ...

. In 1918, he described vibrations and their resonances mathematically, as the

Duffing equation The Duffing equation (or Duffing oscillator), named after Georg Duffing (1861–1944), is a non-linear second-order differential equation used to model certain damped and driven oscillators. The equation is given by :\ddot + \delta \dot + \ ...

. Georg Duffing's equation for vibration theory is a standard model for nonlinear vibration. Since the 1970s, it has been popular in

chaos theory Chaos theory is an interdisciplinary area of scientific study and branch of mathematics focused on underlying patterns and deterministic laws of dynamical systems that are highly sensitive to initial conditions, and were once thought to have co ...

.Ivana Kovacic, Michael J. Brennan: The Duffing Equation: Nonlinear Oscillators and Their Behaviour, John Wiley & Sons, 2011, p. 1

Family and career

Georg Duffing was born in 1861 in the Baden town of Waldshut as the eldest son of merchant Christian Duffing and his wife Julie Spies. In 1862, the family moved to

Mannheim Mannheim (; Palatine German: or ), officially the University City of Mannheim (german: Universitätsstadt Mannheim), is the second-largest city in the German state of Baden-Württemberg after the state capital of Stuttgart, and Germany's 2 ...

, where the

father-in-law A parent-in-law is a person who has a legal affinity with another by being the parent of the other's spouse. Many cultures and legal systems impose duties and responsibilities on persons connected by this relationship. A person is a child-in-law ...

owned a carpentry business. In high school, Duffing showed a particular talent for mathematics and music. Due to a heart defect, he abandoned his initial intention of pursuing a military career and enrolled from 1878 to 1883 at the

Karlsruhe Institute of Technology The Karlsruhe Institute of Technology (KIT; german: Karlsruher Institut für Technologie) is a public research university in Karlsruhe, Germany. The institute is a national research center of the Helmholtz Association. KIT was created in 2009 w ...

, successively in mathematics, engineering, and mechanical engineering. Despite his heart defect, he won the Baden gymnastics championships. After completing his studies, possibly without taking an examination, Duffing joined

Cologne Cologne ( ; german: Köln ; ksh, Kölle ) is the largest city of the German western States of Germany, state of North Rhine-Westphalia (NRW) and the List of cities in Germany by population, fourth-most populous city of Germany with 1.1 m ...

Deutz AG Deutz AG is a German internal combustion engine manufacturer, based in Porz, Cologne, Germany. History The company was founded by Nicolaus Otto, the inventor of the four-stroke internal combustion engine, and his partner Eugen Langen on 31 ...

and contributed to the development of a gas engine that was successfully presented in 1905. In 1910, Duffing interned in the US at

Westinghouse Electric The Westinghouse Electric Corporation was an American manufacturing company founded in 1886 by George Westinghouse. It was originally named "Westinghouse Electric & Manufacturing Company" and was renamed "Westinghouse Electric Corporation" in ...

, a company leading in energy transmission. Returning to Germany, Duffing settled in Berlin in 1913 as an inventor and independent vibration scientist. Duffing attended

Max Planck Max Karl Ernst Ludwig Planck (, ; 23 April 1858 – 4 October 1947) was a German theoretical physicist whose discovery of energy quanta won him the Nobel Prize in Physics in 1918. Planck made many substantial contributions to theoretical p ...

's lectures on

quantum physics Quantum mechanics is a fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles. It is the foundation of all quantum physics including quantum chemistry, qua ...

and conducted research with the support of Eugen Meyer at the Technical University of Berlin-Charlottenburg. In 1918, he published his widely noticed work on pendulum oscillations, later known as the Duffing oscillator. In 1921, financially troubled, he joined the Hamburg-based Ölwerke Stern-Sonneborn AG (Ossag), where he dealt with the friction behavior and viscosity of lubricating oils and headed the company's development laboratory. Due to a lubricating oil-related accident of the

SS Cap Arcona SS ''Cap Arcona'', named after Cape Arkona on the island of Rügen, was a large German ocean liner, later a ship of the German Navy, and finally a prison ship. A flagship of the Hamburg Südamerikanische Dampfschifffahrts-Gesellschaft ("Hambur ...

in 1929, Duffing, who had to fight for his reputation in court due to internal politics in the company, fell into professional ruin. In 1931, Duffing moved back to Berlin. Due to air raids on Berlin, he sought refuge in Schwedt, where he died on April 5, 1944. Georg Duffing was buried in Berlin at the Friedhöfe vor dem Halleschen Tor. Duffing held various technical patents in Germany and the USA.

Publications

* ''Beitrag zur Bestimmung der Formveränderung gekröpfter Kurbelwellen'', Springer, Berlin, 1906. * ''Erzwungene Schwingungen bei veränderlicher Eigenfrequenz'', F. Vieweg, Braunschweig, 41/42, 1918. * ''Reibungsversuch am Gleitlager, Verein Deutscher Ingenieure -Zeitschrift'', 72 (15), 495–499, 1928. * ''Elastizität und Reibung beim Riementrieb'', Forschung auf dem Gebiete des Ingenieurwesens, 2 (3), 99–104, 1931. * ''Messung der Zähigkeit durch gleichförmige koaxiale Bewegung einer Kugel in einem Kreiszylinder'', Zeitschrift für Angewandte Mathematik und Mechanik, 13, 366–373, 1933. * ''A new form of absolute viscometer'', First World Petroleum Congress (London, UK), July 18–24, 1933.

References

External links

Georg Duffing
on Atomosyd.net
Duffing Oscillator at Scholarpedia
{{DEFAULTSORT:Duffing, Georg People from Waldshut-Tiengen 20th-century German non-fiction writers 1944 deaths German inventors German engineers 1861 births

Family and career

Publications

Further reading

References

External links