Otto Mohr

Christian Otto Mohr (October 8, 1835 - October 2, 1918) was a German civil engineer, one of the most celebrated of the nineteenth century.

Mohr was born the son of a landowning family in Wesselburen in the Holstein region and attended the Polytechnic School in Hanover.

Starting in 1855, his early working life was spent in railroad engineering for the Hanover and Oldenburg state railways, designing some famous bridges and making some of the earliest uses of steel trusses.

Even during his early railway years, Mohr's interest had been attracted by the theories of mechanics and the strength of materials, and in 1867, he became professor of mechanics at Stuttgart Polytechnic and, in 1873, at Dresden Polytechnic. Mohr had a direct and unpretentious lecturing style that was popular with his students.

In 1874, Mohr formalised the, until then only intuitive, idea of a statically determinate structure.

Mohr was an enthusiast for graphical tools and developed the method, for visually representing stress in three dimensions, previously proposed by Carl Culmann. In 1882, he famously developed the graphical method for analysing stress known as Mohr's circle and used it to propose an early theory of strength based on shear stress. He also developed the Williot-Mohr diagram for truss displacements and the Maxwell-Mohr method for analysing statically indeterminate structures.

He retired in 1900 and died in Dresden.

Bibliography

• Timoshenko, S. P. (1953) History of Strength of Materials ISBN 0070647259