Leonid Vladimirovich Assur

Leonid Vladimirovich Assur , Russian Леони́д Влади́мирович Ассу́р , (born March 31, 1878 in Rybinsk ; † May 19, 1920 in Voronezh ) was a Russian mechanical engineer.

His father was a customs officer on the railroad. Assur lost his mother at the age of seven and was sent by his father to two aunts in Estonia ( Wesenberg ). From 1892 he went to the grammar school in Warsaw and from 1895 to that of Grodno , where his father now lived. At high school he was a very good student and learned Latin, Greek, French and German (later he also learned English). From 1897 he studied at the mathematical and physical faculty of the Lomonossow University , where one of his teachers was Nikolai Jegorowitsch Zhukowski , who also introduced him to the theory of joint mechanisms. After graduating in 1901, he continued his studies at the Moscow Technical University, where IN Mertsalov (1866-1948) taught machine elements. After graduating as an engineer in 1906, he went to Saint Petersburg, but initially could not find a job at a university and worked for the state bridge construction office. In 1907 a mechanics department was established at the state university and Assur was able to become an assistant. Professor for applied mechanics was Viktor Lwowitsch Kirpitschow and for theoretical mechanics IV Meshchersky (1859-1939). He was involved in a widespread mechanics textbook by Meshchersky and published two textbooks of his own in 1911. In 1916 he defended his habilitation thesis (Russian doctorate) on the classification of joint mechanisms. Further research was initially interrupted by his work as an engineer for the war effort in World War I. Living conditions in Saint Petersburg had deteriorated significantly during and after the war. After the October Revolution, there was a heavy teaching load (Polytechnic Institute, Forestry College). His health deteriorated and in 1919 he went to live with his family in Voronezh. He had two operations and did not wake up after the second operation.

Assur began a classification of plane machine mechanisms based on topology (published 1914/15). The mechanisms were analyzed according to structural kinematic groups. His work remained unfinished, was initially hardly noticed in Russia (the classification after Franz Reuleaux was used ) but was taken up and continued by Iwan Iwanowitsch Artobolewski (as well as NG Bruevich (1896–1987) and VV Dobrovolsky (1880–1956)) in the 1930s and so known outside of Russia. His method not only classified the known mechanisms, but also predicted new ones.

He played the piano and composed.

Fonts (selection)

• Analogues of accelerations and their on the dynamic analysis of plane joint mechanisms (Russian), Abh. Polytechn. Saint Petersburg Institute 1909
• Basic properties of the analogs of accelerations in analytical representation (Russian), Abh. Polytechn. Saint Petersburg Institute 1909
• with K. Roerich: Graphical Methods of Determining the Moment of Inertia of Flywheels (Russian), Saint Petersburg 1911
• Velocity and Acceleration in Vector Diagrams of Plane Mechanisms (Russian), Saint Petersburg 1911
• Teaching about normal multi-rod chains and their role in the formation of mechanisms (Russian), Abh. Polytechn. Institute Saint Petersburg 1914 (with addition 1916)
• Application of the theory of normal chains to the general theory of mechanisms (Russian), Abh. Polytechn. Institute Saint Petersburg 1914 (with addition 1918)
• Geometric construction methods for some curved lines (Russian), Saint Petersburg 1916

literature

• Alexander Evgrafov, Denis Kozlikin: Leonid Assur (1878–1920), in: Marco Ceccarelli (Ed.), Distinguished Figures in Mechanism and Machine Science, Volume 3, Springer 2014, pp. 19–40