Downloaded from rsbm.royalsocietypublishing.org on December 26.2010 Stephen Prokofievitch Timoshenko 683 measure of autonomy for the universities.Now,however,the last remnants of these reforms were being liquidated and the Government's attitude towards liberal thought in schools and universities was hardening.At the Kiev Poly- technic the Ministry had insisted on the expulsion of Jewish students in excess of a government-imposed quota.This the governing body of the Polytechnic were reluctant to do and this led to the dismissal of three of the deans,including Timoshenko.This event marked the beginning of a period of more than ten years of uncertainty and hardship in his life Period of upheaval For the next two years,Timoshenko and his family lived on what he could manage to earn as a part-time teaching assistant(paid by the hour)and a sum of money that was fortuitously awarded to him at that time as a part of the Jourawsky prize.His financial situation improved in 1912 when,following an expansion of the Russian naval shipbuilding programme,he was offered the job of consultant to the shipyards in matters relating to structural strength.Later that year he decided to spend the rest of the Jourawsky prize on a visit to Europe.Much of the summer was spent in Switzerland where he and Alexandra were able to enjoy their favourite outdoor activity,hiking.Before returning home to Russia,Timoshenko made his first trip to England to attend the Mathematical Congress in Cambridge.The Congress members were housed in students'rooms in St John's College and this accommodation seemed to him luxurious compared to those in his homeland.The morning after his arrival he had breakfast at a table with A.E.H.Love,Horace Lamb and Levi-Civita, but his(then)inadequate knowledge of English prevented him getting to know them well. In January 1913,the government softened sufficiently to reinstate Timoshenko as a professor at the Institute of Engineers of Ways of Communication,and there was a brief period of relief to his hardships.During this lull in the storm, he continued his scientific work.For some time he had been interested in the theory of elasticity and had succeeded in solving a number of new problems in this field.Among these was the determination of the 'shear centre'for bending of a beam having a semi-circular cross section.In a way this result was a 'fringe benefit',and the way in which he arrived at it may be of interest.First,he solved for the distribution of shear stresses over the cross section of a cantilever beam of circular section loaded transversely at the free end.Having this result,he observed that there was no interaction between the two halves of the beam on either side of a vertical plane of symmetry.Hence,by integrating the shear stresses over half of the cross section and finding the point of application of their resultant,he obtained that point in the cross section at which a vertical load IP would have to be applied to produce vertical deflexion of a semi-circular beam without twist.It is this simple unsophisticated approach,so characteristic of Timoshenko's work,that arouses our admiration.It was soon after this that he published his second book,Theory of elasticity,which was the forerunner of several of his later books published in America. 44
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Downloaded from rsbm.royalsocietypublishing.org on December 26,2010 684 Biographical Memoirs The normal academic life so recently re-established was interrupted by the start of the first world war.The teaching routine was altered and many of the professors had their research efforts diverted to military aspects.Mobilization and the consequent increase in rail traffic had revealed inadequacies in the strength of much of the railroad tracks and Timoshenko was asked for advice on how to strengthen them.He simplified the problem to one of a beam on an elastic foundation and in this way was able to show immediately how the stresses depended on the dimensions of the rail and the rigidity of the track. The war with Germany also marked the beginning of a period of great social and political upheaval in Russia.The next few years were very trying for Timoshenko and his family,but it is characteristic of him that during this time he wrote and succeeded in getting published an elementary book on Strength of materials without calculus.Conditions worsened for him and his family after 1914 to the point where he decided to leave Russia.The Bolshevik grip on the country was tightening and it was felt that the professors should leave for Yugoslavia which had declared its willingness to accept Russian refugees. It was hoped that Poland would shortly enter an alliance with the Volunteer Army and drive the Bolsheviks from power,but events proved otherwise and there was to be no return to the homeland.The journey to Yugoslavia was not without incident.The train that took Timoshenko and his family from Kiev was the last that managed to leave,and they were able to board it only because the official in charge of the evacuation happened to have been one of his students. Timoshenko had been offered the chair of strength of materials in Zagreb and, knowing the difficulties in obtaining accommodation there,had decided to find temporary rooms in a nearby village.In this he was greatly helped by an engineer who had studied one of Timoshenko's books while a prisoner of war;Timoshenko never dreamt that his book could have such practical value!When the academic year started it was necessary to find accommodation in Zagreb itself,but this proved almost impossible and Timoshenko and his family were obliged to move into the rooms intended as his future office and laboratory.It was fortunate that these rooms had electricity,gas and water,for they were to be his home for two years.While a bed was purchased for Timoshenko and Alexandra,the children slept on mattresses of hay-filled sacks on beds made from stools lashed together with rope.The children were taught Croatian at school while Timoshenko taught himself by reading the paper and from discussions with the Croatian professor of theoretical mechanics who also knew Russian.After his first year of teaching he spent part of the summer vacation touring Western European engineering laboratories.In London he found that,although he could read English without difficulty,he was not sufficiently accustomed to English pronunciation to understand the spoken language.It is typical of his untiring energy and broad interest that he should remedy this situation by attending a course on Egyptian culture at the British Museum. In Zagreb he also resumed his scientific work and published several papers in English with the help of R.V.Southwell and A.E.H.Love.One of these was a discussion of the corrections to the differential equation for transverse
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