E-Book, Englisch, Band 145, 271 Seiten, eBook
What It Is, Why It Matters
E-Book, Englisch, Band 145, 271 Seiten, eBook
Reihe: Solid Mechanics and Its Applications
ISBN: 978-1-4020-5597-3
Verlag: Springer Netherland
Format: PDF
Kopierschutz: 1 - PDF Watermark
Zielgruppe
Research
Autoren/Hrsg.
Weitere Infos & Material
Historical Background.- Constant Amplitude Fatigue.- Variable Amplitude and Multiaxial Fatigue.- Fatigue Design.- The Uncracked Situation.- The Cracked Situation.- Fatigue Crack Paths.- Why Metal Fatigue Matters.
2 Historical Background (p. 7)
2.1 Introduction
Early in the history of engineering design, there was a recognition of the need to know the different ways in which a material or component could fail. Failure was usually associated with fracture, or with excessive deformation. Failure under static loads, tensile, compressive and shear, became widely known. Much early design aimed at making a component or a structure that would last indefinitely.
Metal fatigue has been of interest for about 170 years. This interest dates back to the development of the steam engine, mechanical transport, and the more extensive use of mechanical devices. This mechanisation meant that many components were subjected to fatigue loads, and fatigue failure was beginning to become a common occurrence. The history of metal fatigue, from an engineering viewpoint, is well documented but early references are often difficult to locate.
Most books on metal fatigue include a historical summary, usually concentrating on mechanical descriptions. The best recent history, on mechanical descriptions of metal fatigue, is by Schütz (1996). It includes over 500 references, mostly in English and German.
The first use of the term fatigue in print appears to be by Braithwaite (1854), although in his paper Braithwaite states that it was coined by a Mr Field. The general opinion had developed (Frost et al. 1974) that the material had tired of carrying the load, or that the continual re-application of a load had in some way exhausted the ability of the material to carry load.
The use of the term has survived to this day. Since fatigue failures also occur in many non metallic materials the term metal fatigue is often used, as in this book, to denote the particular kind of fatigue that occurs in metallic materials, components and structures.
The first known catastrophic fatigue failure, involving major loss of life, was the Versailles (France) railway accident in 1842 (Smith 1990). The train was unusually long, with 17 carriages hauled by two steam engines. The front axle of the leading, four wheeled engine failed due to metal fatigue and the body of the leading engine fell to the ground.
The second engine smashed it to pieces. Following carriages passed over the wreck and some were set on fire. This, and numerous other railway axle failures, led to extensive investigations into the nature of metal fatigue (Parsons 1947, Smith 1990, Schütz 1996).
The first known, reasonably well documented, metal fatigue failures were in clock mainsprings (Wayman et al. 2000). The use of uncoiling springs, rather than descending weights, as a driving force was an important factor in the development of clocks for general use, and appears to have started in the early fifteenth century.
By the late eighteenth century the technology for the manufacture of durable watch and clock mainsprings was well established, a detailed description of the state of the art of making watch springs was published by Blakey (1780). Even so, high quality watches and clocks were designed (and still are) so that a broken mainspring could easily be replaced.
