August Wöhler
Encyclopedia
August Wöhler was a German
engineer
, best remembered for his systematic investigations of metal fatigue
.
Born in the town of Soltau
, the son of local teacher
Georg Heinrich Wöhler showed early mathematical ability and won a scholarship
to study at the Technische Hochschule in Hannover, under the direction of Karl Karmarsch
.
In 1840, he was recruited to the Borsig works in Berlin
where he worked on the manufacture of rail tracks
. In 1843, after a brief stay in Hannover, he started to receive instruction in locomotive
driving in Belgium
, returning as an engineer on the Hannover to Lehrte
line. By 1847, Wöhler was chief superintendent of rolling stock
on the Lower Silesia-Brandenberg Railroad. His growing reputation led to his appointment in 1852 by the Prussia
n minister of commerce to investigate the causes of fracture
in railroad axle
s, work that was to occupy Wöhler over the next two decades.
The railroad was nationalised in 1854 and the recognition of his keen administration and technical leadership resulted in his appointment as director of the newly formed Imperial Railways
, based at the board's headquarters in Strasbourg
, a post he held until his retirement in 1889.
Wöhler started his axle investigations by research into the theory of elasticity
and was led, in 1855, to a method for predicting the deflection of lattice beam
s that anticipated the work of Émile Clapeyron1. He also introduced the practice of supporting one end of a bridge on roller bearings to allow for thermal expansion.
His work on fatigue
marks the first systematic investigation of S-N Curves, also known as Wöhler curves, to characterise the fatigue behaviour of materials2. Such curves can be used to minimise the problem of fatigue by lowering the stress at critical points in a component. Wohler showed clearly that fatigue occurs by crack growth from surface defects until the product can no longer support the applied load. The history of a fracture can be understood from a study of the fracture surface. He developed apparatus for repeated loading of railway axles, mainly because many accidents were caused by sudden fatigue fracture. The presentation of his work at the Paris Exposition
in 1867 brought it to a wide international audience3,4.
Wöhler was an advocate of state standardisation, testing and certification of iron
and steel
.
He died in Hannover in 1914.
Germany
Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...
engineer
Engineer
An engineer is a professional practitioner of engineering, concerned with applying scientific knowledge, mathematics and ingenuity to develop solutions for technical problems. Engineers design materials, structures, machines and systems while considering the limitations imposed by practicality,...
, best remembered for his systematic investigations of metal fatigue
Metal Fatigue
Metal Fatigue , is a futuristic science fiction, real-time strategy computer game developed by Zono Incorporated and published by Psygnosis and TalonSoft .-Plot:...
.
Born in the town of Soltau
Soltau
- Middle Ages :The region of the Lüneburg Heath had already been settled by the start of the New Stone Age about 4,000 years ago. The Soltau area was initially occupied by a few individual farms. The parish of Soltau was probably founded around 830 and the first wooden church Sante Johannis...
, the son of local teacher
Teacher
A teacher or schoolteacher is a person who provides education for pupils and students . The role of teacher is often formal and ongoing, carried out at a school or other place of formal education. In many countries, a person who wishes to become a teacher must first obtain specified professional...
Georg Heinrich Wöhler showed early mathematical ability and won a scholarship
Scholarship
A scholarship is an award of financial aid for a student to further education. Scholarships are awarded on various criteria usually reflecting the values and purposes of the donor or founder of the award.-Types:...
to study at the Technische Hochschule in Hannover, under the direction of Karl Karmarsch
Karl Karmarsch
Karl Karmarsch was a German educator, founding director of the Polytechnic School in Hannover, later to become the University of Hannover.In 1863, he was elected a foreign member of the Royal Swedish Academy of Sciences....
.
In 1840, he was recruited to the Borsig works in Berlin
Berlin
Berlin is the capital city of Germany and is one of the 16 states of Germany. With a population of 3.45 million people, Berlin is Germany's largest city. It is the second most populous city proper and the seventh most populous urban area in the European Union...
where he worked on the manufacture of rail tracks
Rail tracks
The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, sleepers and ballast , plus the underlying subgrade...
. In 1843, after a brief stay in Hannover, he started to receive instruction in locomotive
Locomotive
A locomotive is a railway vehicle that provides the motive power for a train. The word originates from the Latin loco – "from a place", ablative of locus, "place" + Medieval Latin motivus, "causing motion", and is a shortened form of the term locomotive engine, first used in the early 19th...
driving in Belgium
Belgium
Belgium , officially the Kingdom of Belgium, is a federal state in Western Europe. It is a founding member of the European Union and hosts the EU's headquarters, and those of several other major international organisations such as NATO.Belgium is also a member of, or affiliated to, many...
, returning as an engineer on the Hannover to Lehrte
Lehrte
Lehrte is a town in the district of Hanover, in Lower Saxony, Germany. It is situated approximately 17 km east of Hanover. Lehrte is a picturesque town with a population of 45,000 and a modern infrastructure, combined with local culture and an interesting history.-History:The first documented...
line. By 1847, Wöhler was chief superintendent of rolling stock
Rolling stock
Rolling stock comprises all the vehicles that move on a railway. It usually includes both powered and unpowered vehicles, for example locomotives, railroad cars, coaches and wagons...
on the Lower Silesia-Brandenberg Railroad. His growing reputation led to his appointment in 1852 by the Prussia
Prussia
Prussia was a German kingdom and historic state originating out of the Duchy of Prussia and the Margraviate of Brandenburg. For centuries, the House of Hohenzollern ruled Prussia, successfully expanding its size by way of an unusually well-organized and effective army. Prussia shaped the history...
n minister of commerce to investigate the causes of fracture
Fracture
A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...
in railroad axle
Axle
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...
s, work that was to occupy Wöhler over the next two decades.
The railroad was nationalised in 1854 and the recognition of his keen administration and technical leadership resulted in his appointment as director of the newly formed Imperial Railways
Deutsche Bahn
Deutsche Bahn AG is the German national railway company, a private joint stock company . Headquartered in Berlin, it came into existence in 1994 as the successor to the former state railways of Germany, the Deutsche Bundesbahn of West Germany and the Deutsche Reichsbahn of East Germany...
, based at the board's headquarters in Strasbourg
Strasbourg
Strasbourg is the capital and principal city of the Alsace region in eastern France and is the official seat of the European Parliament. Located close to the border with Germany, it is the capital of the Bas-Rhin département. The city and the region of Alsace are historically German-speaking,...
, a post he held until his retirement in 1889.
Wöhler started his axle investigations by research into the theory of elasticity
Elasticity (physics)
In physics, elasticity is the physical property of a material that returns to its original shape after the stress that made it deform or distort is removed. The relative amount of deformation is called the strain....
and was led, in 1855, to a method for predicting the deflection of lattice beam
Lattice girder
A lattice girder is a girder where the flanges are connected by a lattice web. This type of design has been supplanted in modern construction with welded or bolted plate girders, which use more material but have lower fabrication and maintenance costs...
s that anticipated the work of Émile Clapeyron1. He also introduced the practice of supporting one end of a bridge on roller bearings to allow for thermal expansion.
Fatigue Studies
Fatigue (material)
'In materials science, fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading. The nominal maximum stress values are less than the ultimate tensile stress limit, and may be below the yield stress limit of the material.Fatigue occurs...
marks the first systematic investigation of S-N Curves, also known as Wöhler curves, to characterise the fatigue behaviour of materials2. Such curves can be used to minimise the problem of fatigue by lowering the stress at critical points in a component. Wohler showed clearly that fatigue occurs by crack growth from surface defects until the product can no longer support the applied load. The history of a fracture can be understood from a study of the fracture surface. He developed apparatus for repeated loading of railway axles, mainly because many accidents were caused by sudden fatigue fracture. The presentation of his work at the Paris Exposition
World's Fair
World's fair, World fair, Universal Exposition, and World Expo are various large public exhibitions held in different parts of the world. The first Expo was held in The Crystal Palace in Hyde Park, London, United Kingdom, in 1851, under the title "Great Exhibition of the Works of Industry of All...
in 1867 brought it to a wide international audience3,4.
Wöhler was an advocate of state standardisation, testing and certification of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
and steel
Steel
Steel is an alloy that consists mostly of iron and has a carbon content between 0.2% and 2.1% by weight, depending on the grade. Carbon is the most common alloying material for iron, but various other alloying elements are used, such as manganese, chromium, vanadium, and tungsten...
.
He died in Hannover in 1914.