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Overburden is also used for all soil and ancillary material above the bedrock horizon in a given area. By analogy, overburden is also used to describe the soil and other material that lies above a specific geologic feature , such as a buried astrobleme , or above an unexcavated site of archeological interest.
Fatigue has traditionally been associated with the failure of metal components which led to the term metal fatigue. In the nineteenth century, the sudden failing of metal railway axles was thought to be caused by the metal crystallising because of the brittle appearance of the fracture surface, but this has since been disproved. [ 1 ]
Specifically in sedimentology, a bed can be defined in one of two major ways. [2] First, Campbell [3] and Reineck and Singh [4] use the term bed to refer to a thickness-independent layer comprising a coherent layer of sedimentary rock, sediment, or pyroclastic material bounded above and below by surfaces known as bedding planes.
Low cycle fatigue (LCF) has two fundamental characteristics: plastic deformation in each cycle; and low cycle phenomenon, in which the materials have finite endurance for this type of load. The term cycle refers to repeated applications of stress that lead to eventual fatigue and failure; low-cycle pertains to a long period between applications.
Rock core samples, the product of a diamond rig.A pied butcherbird perches nearby.. A core sample is a cylindrical section of (usually) a naturally-occurring substance. Most core samples are obtained by drilling with special drills into the substance, such as sediment or rock, with a hollow steel tube, called a core drill.
Vibration fatigue is a mechanical engineering term describing material fatigue, caused by forced vibration of random nature. An excited structure responds according to its natural-dynamics modes, which results in a dynamic stress load in the material points. [ 1 ]
A Soviet-designed drill used a motor to provide vertical vibration to the barrel of the drill at 50 Hz; the drill had an outer diameter of 0.4 m, and in tests at Vostok Station in the Antarctic drilled a 6.5 m hole, with a 1.2 m drilling run taking between 1 and 5 minutes to complete. The drill's steel edges compacted snow into the core, which ...
[3] According to the standards, the constraining dimension of the specimen is the thickness of the material. Compact tension specimens are used for experiments where there is a shortage of material available due to their compact design. For rolled materials the notch should be aligned with the roll direction where the material is weakest.