TIMOSHENKO, STEPAN [STEPHEN] PROKOF’EVICH

(b. Shpotovka, Chernigovskaia gubernüa [now Sumyskaia oblast, Ukrainian S.S.R. ], Russia, 22 December 1878; d. Wuppertal, Federal Republic of Germany, 25 May 1972)

mechanics.

Timoshenko’s father, Prokofü Stepanovich, was a land surveyor; his mother, Josefina lakovlevna Sarnovskaia, was a housewife.

In 1889 Timoshenko entered the Practical School in Romny, where one of his classmates was Abram Fedorovich Ioffe. In 1896 timoshenko enrolled in the Institute of Railroad Transport in St. Petersburg, from which he graduated in 1901. The next year he started teaching there. In August of that year he married Aleksandra Arkhangelskaia, a medical student. They had three children.

In 1903 Timoshenko moved to the department of stength of materials at the St. Petersburg Polytechnical Institute. Three years later he won the competition for the chair in the department of strength of materials at the Kiev Polytechnical Institute, but in 1911 he was dismissed from the institute because of his opposition to the Ministry of Education’s quotas for the admission of Jews.

Timoshenko then returned to St. Petersburg, where he taught as a nonstaff instructor at the Polytechnical Institute and the Electrotechnical Institute. In 1913 he was reinstated in the state service (as the result of a public petition that he had initiated) and resumed his work at the Institute of Railroad Transport as the head of the department of theoretical mechanics. During World War I, Timoshenko served as a consultant on materials strength at military plants as well as at the Ministry of Communications. From 1918 to 1920 he was again at the Kiev Polytechnical Institute. At the same time he took part in the organization of the Ukrainian Academy of Sciences and became the head of its Institute of Mechanics.

In 1920 Timoshenko emigrated to Yugoslavia, where for two years he taught at the Zagreb Polytechnical Institute. Then he move to the United States. He first worked in research departments of several engineering companies in Philadelphia and Pittsburg (including Westinghouse from 1923 to 1927), and then lectured at a number of universities. During 1927–1936 Timoshenko was a professor at the University of Michigan, and from 1936 until 1955 at Standford University.

As a scholar Timoshenko was greatly influenced by Ivan Grigorievich Bubnov, Viktor Lvovich Kirpichev, and Aleksei Nikolaevich Krylov in Russia, and by August Föppl, Woldemar Voigt, Felix Klein, and Ludwig Prandtl in Germany. He traveled to Europe practically every year (except during the two world wars), and he maintaine scientific contacts with colleagues all over the world.

Timoshenko always did research along with his teaching. Despite his long experience as a lecturer, he firmly believed that his lectures could be successful only if he had previously treated the subject in written form. Because of this belief and of his great productivity, he left an enormous number of courses published and republished in Russian and in English (dating from 1908) and covering practically all areas of pure and applied mechanics. These courses are remarkable not only for their detailed exposition of material but also for their inclusion of the author’s scientific researches and results.

Timoshenko’s first paper (1905) was devoted to resonance in shafts. A group of his papers concerning the theory of stability of flange beams, bars, plates, and shells was gathered in Collection of Problems in Strength of Materials (1910). The book was awarded the D. I. Zhurvavskü Gold Medal and Prize by the Institute of Railroad Transport.

Another group of Timoshenko’s papers dealt with the classical theory of elasticity. He developed an approximative method of solving the plane problem of elasticity and a method of calculating stresses in plates with holes, in circular rings, and in rods subject to bending and torsion. He also investigated circular and rectangular plates and, as was typical for him, paid much attention to effective approximative procedures.

Being interested in the immediate applications of his investigations in mechanics, Timoshenko was involved in the design of bridges, including suspension bridges. During World War I he advised the government on the practical problems of the strength of rails (which were especially critical in view of the overloaded railroads), as well as of shafts and turbines. He was concerned with the fatigue of materials associated with the concentration of stress near holes. In addition to the theory of the strength of materials, Timoshenko worked out experimental methods of investigating stress, and carried out experiments on stability, strength, and buckling of beams and plates. He made an extraordinary contribution to the organization of training laboratories at all the educational institutions where he taught for more than half a century.

Timoshenko also published works on the mechanical properties of materials, on shock loads, on applications of the theory of vibrations to engineering, and on the history of mechanics (particularly the strength of materials).

In 1919 Timoshenko was elected full member of the Ukrainian Academy of Sciences; in 1928 he became corresponding member, and in 1964 full member, of the Soviet Academy of Sciences. He was a corresponding, full, or honorary member of the academies of science of the United States, Poland, France, and Italy, and of the Royal Society of London, and held honorary doctorates from a number of universities. His works were awarded medals in Britain and the United States. The American Society of Mechanical Engineers established two medals named for him, and in 1957 he was the first recipient of one of them, “for an extraordinary contribution to creation of a new era in applied mechanics, for the personal example and leadership in work.”

Timoshenko’s hobby was travel. He traveled throughout Europe, and after World War II twice went to the Soviet Union, where he visited his birthplace, as well as Kiev, Leningrad, and Moscow. He loved music and literature, and was a gifted writer. In 1963 he published his memoirs (parts of which were used for the preparation of this article).

After his retirement in 1944, Timoshenko became professor emeritus at Stanford University (though he continued to teach on a limited basis until 1955). He remained in the United States until 1960, when he moved to the Federal Republic of Germany, where his daughter lived.

BIBLIOGRAPHY

I. Original Works. Timsohenko wrote more than 120 papers, the most important of which were published in The Collected Papers (New York, 1953) and in Ustoichivost sterzhnei, plastin i obolochek: Izbrannye trudy (“Stability of Strings, Plates, and Shells: Selected Works”; Moscow, 1971). To these should be added the first and the last of Timoshenko’s papers: “K voprosu o iavleniiakh rezonansa v valakh” (“On the Problem of Resonance Phenomena in Shafts”), in Vestnik obshchestva tekhnologov, 19 , no. 7 (1905), 266; and “Deflexion of Strings and Beams,” in Miscellany Dedicated to the Memory of the Late AcademicianJ. M. Klitcheff (Belgrade, 1970).

Timoshenko’s books include Advanced Dynamics (New York, 1948), written with D. H. Young; History of Strength of Materials (New York, 1953); Vibration Problems in Engineering, 3rd ed. (New York, 1955), written with D.H. Young; Engineering Mechanics, 4th ed., 2 vols. (New York, 1956), written with D. H. Young; Strength of Materials, pt. 11 , Advanced Theory and Problems, 3rd ed., 2 vols. (New York, 1956); Theory of Structures, 2nd ed. (New York, 1965), written with D. H. Young; Theory of Plates and Shells, 2nd ed. (New York, 1959), written with S. Woinwski-Krieger; Theory of Elasticity, 3rd ed. (New York, 1970), written with J. N. Goodier. His memoirs are Vospominaniia (Paris, 1963), trans. by Robert Addisas As I Remember (New York, 1968).

II. Secondary Literature. E. I. Grigoluik, “Scientific Works of S. P. Timoshenko,” in Lssledovaniia po teorii plastin i obolochek (Kazan, 1972), 3–54; and J. M. Lessels, —, in Contributions to the Mechanics of Solids Dedicated to Stephen Timoshenko by His Friends on the Occasion of His sixtieth Birthday (New York, 1938).

V. J. Frenkel