-
1 Wöhler, August
SUBJECT AREA: Metallurgy[br]b. 22 June 1819 Soltau, Germanyd. 21 June 1914 Hannover, Germany[br]German railway engineer who first established the fatigue fracture of metals.[br]Wöhler, the son of a schoolteacher, was born at Soltau on the Luneburg Heath and received his early education at his father's school, where his mathematical abilities soon became apparent. He completed his studies at the Technical High School, Hannover.In 1840 he obtained a position at the Borsig Engineering Works in Berlin and acquired there much valuable experience in railway technology. He trained as an engine driver in Belgium and in 1843 was appointed as an engineer to the first Hannoverian Railway, then being constructed between Hannover and Lehrte. In 1847 he became Chief Superintendent of rolling stock on the Lower Silesian-Brandenhurg Railway, where his technical abilities influenced the Prussian Minister of Commerce to appoint him to a commission set up to investigate the reasons for the unusually high incidence of axle failures then being encountered on the railways. This was in 1852, and by 1854, when the Brandenburg line had been nationalized, Wöhler had already embarked on the long, systematic programme of mechanical testing which eventually provided him with a clear insight into the process of what is now referred to as "fatigue failure". He concentrated initially on the behaviour of machined iron and steel specimens subjected to fluctuating direct, bending and torsional stresses that were imposed by testing machines of his own design.Although Wöhler was not the first investigator in this area, he was the first to recognize the state of "fatigue" induced in metals by the repeated application of cycles of stress at levels well below those that would cause immediate failure. His method of plotting the fatigue stress amplitude "S" against the number of stress cycles necessary to cause failure "N" yielded the well-known S-N curve which described very precisely the susceptibility to fatigue failure of the material concerned. Engineers were thus provided with an invaluable testing technique that is still widely used in the 1990s.Between 1851 and 1898 Wöhler published forty-two papers in German technical journals, although the importance of his work was not initially fully appreciated in other countries. A display of some of his fracture fatigue specimens at the Paris Exposition in 1867, however, stimulated a short review of his work in Engineering in London. Four years later, in 1871, Engineering published a series of nine articles which described Wöhler's findings in considerable detail and brought them to the attention of engineers. Wöhler became a member of the newly created management board of the Imperial German Railways in 1874, an appointment that he retained until 1889. He is also remembered for his derivation in 1855 of a formula for calculating the deflections under load of lattice girders, plate girders, and other continuous beams resting on more than two supports. This "Three Moments" theorem appeared two years before Clapeyron independently advanced the same expression. Wöhler's other major contribution to bridge design was to use rollers at one end to allow for thermal expansion and contraction.[br]Bibliography1855, "Theorie rechteckiger eiserner Brückenbalken", Zeitschrift für Bauwesen 5:122–66. 1870, "Über die Festigkeitversuche mit Eisen und Stahl", Zeitschrift für Bauwesen 20:73– 106.Wöhler's experiments on the fatigue of metals were reported in Engineering (1867) 2:160; (1871) 11:199–200, 222, 243–4, 261, 299–300, 326–7, 349–50, 397, 439–41.Further ReadingR.Blaum, 1918, "August Wöhler", Beiträge zur Geschichte der Technik und Industrie 8:35–55.——1925, "August Wöhler", Deutsches biographisches Jahrbuch, Vol. I, Stuttgart, pp. 103–7.K.Pearson, 1890, "On Wöhler's experiments on alternating stress", Messeng. Math.20:21–37.J.Gilchrist, 1900, "On Wöhler's Laws", Engineer 90:203–4.ASD
См. также в других словарях:
ГЕРМАНИЯ — (нем. Deutschland). *** *** *** Исторический очерк В истории Г. можно выделить след. осн. периоды: 1) первобытнообщинный строй на терр. Г. и начало зарождения классового общества (до 6 в. н. э.). 2) Раннефеодальный период (6 11 вв.), в котором… … Советская историческая энциклопедия
Albert Hänel — Max Liebermann: Bildnis Geheimrat Prof. Dr. Albert Hänel, 1892, Pastell auf Papier, Kunsthalle Kiel Albert Hänel (* 10. Juni 1833 in Leipzig; † 12. Mai 1918 in Kiel) war ein deutscher Jurist … Deutsch Wikipedia
Bernhard Fürst von Bülow — Bernhard von Bülow, 1895 Bernhard Heinrich Martin Karl von Bülow (* 3. Mai … Deutsch Wikipedia
Andreas Heusler (1834–1921) — Andreas Heusler (* 30. März 1834 in Basel; † 2. November 1921 ebenda) war ein Schweizer Jurist, Rechtshistoriker und Politiker. Inhaltsverzeichnis 1 Leben und öffentliches Wirken 2 Werk 2.1 Werke (Auswahl) … Deutsch Wikipedia
Karl von Wedel — Karl Leo Julius Fürst von Wedel (bis 1914: Graf von Wedel; * 5. Februar 1842 in Oldenburg; † 30. Dezember 1919) war ein preußischer Offizier, zuletzt General der Kavallerie und Diplomat … Deutsch Wikipedia
Ludwig Gümbel — Ludwig Karl Friedrich Gümbel (* 12. März 1874 in Sankt Julian; † 8. Februar 1923 in Berlin) war ein deutscher Schiffbauingenieur. Inhaltsverzeichnis 1 Familie 2 Leben und Wirken 3 Ehrungen … Deutsch Wikipedia
Heinrich zu Schoenaich-Carolath — auf der Titelseite der Berliner Illustrirten Zeitung vom 18. Januar 1892 Heinrich Ludwig Ferdinand Erdmann Deodatus Prinz zu Schoenaich Carolath, Reichsgraf und Reichsfreiherr von Schoenaich (* 24. April 1852 auf Schloss Amtitz bei Guben, heute… … Deutsch Wikipedia
Richard Witting — (eigentlich: Witkowski) (* 19. Oktober 1856 in Berlin; † 22. Dezember 1923 in Berlin) war ein deutscher Jurist, Verwaltungsbeamter, Bankdirektor und Politiker. Er war der Bruder des Journalisten Maximilian Harden und Schwiegervater des Pazifisten … Deutsch Wikipedia
Karl von Wedel — Karl Leo Julius von Wedel ( 5 février 1842 à Oldenbourg 30 décembre 1919 ) est un général et un haut fonctionnaire prussien de l Empire allemand. Il fut général de cavalerie, gouverneur du Reichsland Elsaß Lothringen et diplomate. Biographie Le… … Wikipédia en Français
Ernst Friedel — Ernst Friedel … Deutsch Wikipedia
Anton Opfergelt — Anton Hubert Maria Opfergelt (* 8. Dezember 1850 in Haus Overbach, Barmen (Jülich); † 10. November 1915 in Geilenkirchen) war ein deutscher Politiker und Jurist. Er saß als Abgeordneter im Deutschen Reichstag und im Preußischen Abgeordnetenhaus.… … Deutsch Wikipedia
