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Low-cycle Fatigue
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. Study in fatigue has been focusing on mainly two fields: size design in aeronautics and energy production using advanced calculation methods. The LCF result allows us to study the behavior of the material in greater depth to better understand the complex mechanical and metallurgical phenomena (crack propagation, work softening, strain concentration, work hardening, etc.). History Common factors that have been attributed to low-cycle fatigue (LCF) are high stress levels and a low number of cycles to failure. Many studies have been carried out, particularly in the last 50 years on metals and the relationship between temperature, stres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Deformation
In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the ''relative'' internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve. The relationship between stress and strain is generally linear and reversible up until the yield point and the deformation is elastic. The linear relationship for a material is known as Young's modulus. Above the yield point, some degree of permanent distortion remains after unloading and is termed plastic deformation. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermal Expansion
Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. Temperature is a monotonic function of the average molecular kinetic energy of a substance. When a substance is heated, molecules begin to vibrate and move more, usually creating more distance between themselves. Substances which contract with increasing temperature are unusual, and only occur within limited temperature ranges (see examples below). The relative expansion (also called strain) divided by the change in temperature is called the material's coefficient of linear thermal expansion and generally varies with temperature. As energy in particles increases, they start moving faster and faster weakening the intermolecular forces between them, therefore expanding the substance. Overview Predicting expansion If an equation of state is available, it can be used to predict the values of the thermal expan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buckling
In structural engineering, buckling is the sudden change in shape (deformation) of a structural component under load, such as the bowing of a column under compression or the wrinkling of a plate under shear. If a structure is subjected to a gradually increasing load, when the load reaches a critical level, a member may suddenly change shape and the structure and component is said to have ''buckled''. Euler's critical load and Johnson's parabolic formula are used to determine the buckling stress in slender columns. Buckling may occur even though the stresses that develop in the structure are well below those needed to cause failure in the material of which the structure is composed. Further loading may cause significant and somewhat unpredictable deformations, possibly leading to complete loss of the member's load-carrying capacity. However, if the deformations that occur after buckling do not cause the complete collapse of that member, the member will continue to support the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebar
Rebar (short for reinforcing bar), known when massed as reinforcing steel or reinforcement steel, is a steel bar used as a Tension (physics), tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under Compression (physics), compression, but has weak tensile strength. Rebar significantly increases the tensile strength of the structure. Rebar's surface features a continuous series of ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage. The most common type of rebar is carbon steel, typically consisting of hot-rolled round bars with deformation patterns embossed into its surface. Steel and concrete have similar coefficient of thermal expansion, coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal differential stress (mechanics), stress as the temperature changes. Other readily available ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Chile
The University of Chile ( es, Universidad de Chile) is a public research university in Santiago, Chile. It was founded on November 19, 1842, and inaugurated on September 17, 1843.Fuentes documentales y bibliográficas para el estudio de la historia de Chile. Capítulo III: "La Universidad de Chile 1842 – 1879". 1. La ley orgánica de 1842 www.uchile.cl It is the oldest in the country. It was established as the continuation of the former colonial |
2010 Chile Earthquake
The 2010 Chile earthquake and tsunami ( es, Terremoto del 27F) occurred off the coast of central Chile on Saturday, 27 February at 03:34 local time (06:34 UTC), having a magnitude of 8.8 on the moment magnitude scale, with intense shaking lasting for about three minutes. It was felt strongly in six Chilean regions (from Valparaíso in the north to Araucanía in the south) that together make up about 80 percent of the country's population. According to the United States Geological Survey (USGS) the cities experiencing the strongest shaking—VIII (''Severe'') on the Mercalli intensity scale (MM)—were Concepción, Arauco, and Coronel. According to Chile's Seismological Service, Concepción experienced the strongest shaking at MM IX (''Violent''). The earthquake was felt in the capital Santiago at MM VII (''Very strong'') or MM VIII. Tremors were felt in many Argentine cities, including Buenos Aires, Córdoba, Mendoza, and La Rioja. Tremors were felt as far north as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torre O´Higgins Conce
''Torre'' (plurals ''torri'' and ''torres'') means ''tower'' in seven Romance languages (Portuguese, Spanish, Galician, Catalan, Italian, Occitan and Corsican) and may refer to: Biology * Muir-Torre syndrome, the inherited cancer syndrome * '' Sypharochiton torri'', a mollusc Chess * Carlos Torre Repetto, Mexican chess grandmaster ** Torre Attack, an opening in chess * Eugenio Torre (born 1951), Filipino chess grandmaster * An alternative name for a rook in chess Places Brazil * Torre, a neighborhood in the metropolitan area of Recife England * Torre, Torquay, an area of Torquay in Devon * Torre, Somerset, a hamlet in the county of Somerset France * Torre, Corsica Italy * Torre Annunziata, a comune in the province of Naples in the region of Campania * Torre Archirafi, a frazione in the comune of Riposto in the province of Catania in the region of Sicily * Torre Boldone, a comune in the province of Bergamo in the region of Lombardy * Torre Bormida, a comu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Northridge, Los Angeles
Northridge is a neighborhood in the San Fernando Valley region of the City of Los Angeles. The community is home to California State University, Northridge, and the Northridge Fashion Center. Originally named Zelzah by settlers in 1908, the community was renamed North Los Angeles in 1929 but the appellation sometimes caused confusion between North Hollywood and Los Angeles. In 1938, civic leader Carl S. Dentzel decided to rename the community to Northridge Village, which morphed into modern-day Northridge. The Northridge area can trace its history back to the Tongva people and later to Spanish explorers. It was sold by the Mexican governor Pio Pico to Eulogio de Celis, whose heirs divided it for resale. Population The 2000 U.S. census counted 57,561 residents in the Northridge neighborhood—or , among the lowest population densities for the city. In 2008, the city estimated that the population had increased to 61,993. In 2000 the median age for residents was 32, about averag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Southern California
The University of Southern California (USC, SC, or Southern Cal) is a Private university, private research university in Los Angeles, California, United States. Founded in 1880 by Robert M. Widney, it is the oldest private research university in California. The university is composed of one Liberal arts education, liberal arts school, the University of Southern California academics, Dornsife College of Letters, Arts and Sciences, and 22 Undergraduate education, undergraduate, Graduate school, graduate, and professional schools, enrolling roughly 21,000 undergraduate and 28,500 Postgraduate education, post-graduate students from all 50 U.S. states and more than 115 countries. It is also a member of the Association of American Universities, which it joined in 1969. USC is ranked as one of the top universities in the United States and admission to its programs is considered College admissions in the United States, highly selective. USC has graduated more alumni who have gone on to w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1994 Northridge Earthquake
The 1994 Northridge earthquake was a moment 6.7 (), blind thrust earthquake that occurred on January 17, 1994, at 4:30:55 a.m. PST in the San Fernando Valley region of the City of Los Angeles. The quake had a duration of approximately 10–20 seconds, and its peak ground acceleration of 1.82 ''g'' was the highest ever instrumentally recorded in an urban area in North America. Shaking was felt as far away as San Diego, Turlock, Las Vegas, Richfield, Phoenix and Ensenada. The peak ground velocity at the Rinaldi Receiving Station was , the fastest ever recorded. Two 6.0 aftershocks followed, the first about one minute after the initial event and the second approximately 11 hours later, the strongest of several thousand aftershocks in all. The death toll was 57, with more than 9,000 injured. In addition, property damage was estimated to be $13–50 billion (equivalent to $24–93 billion in 2021), making it one of the costliest natural disasters in U.S. history. Epi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Empirical Constant
In science, an empirical relationship or phenomenological relationship is a relationship or correlation that is supported by experiment and observation but not necessarily supported by theory. Analytical solutions without a theory An empirical relationship is supported by confirmatory data irrespective of theoretical basis such as first principles. Sometimes theoretical explanations for what were initially empirical relationships are found, in which case the relationships are no longer considered empirical. An example was the Rydberg formula to predict the wavelengths of hydrogen spectral lines. Proposed in 1876, it perfectly predicted the wavelengths of the Lyman series, but lacked a theoretical basis until Niels Bohr produced his Bohr model of the atom in 1925.McMullin, Ernan (1968), “What Do Physical Models Tell Us?”, in B. van Rootselaar and J. F. Staal (eds.), Logic, Methodology and Science III. Amsterdam: North Holland, 385–396. On occasion, what was thought to be an e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Equation
In mathematics, an equation is a formula that expresses the equality of two expressions, by connecting them with the equals sign . The word ''equation'' and its cognates in other languages may have subtly different meanings; for example, in French an ''équation'' is defined as containing one or more variables, while in English, any well-formed formula consisting of two expressions related with an equals sign is an equation. ''Solving'' an equation containing variables consists of determining which values of the variables make the equality true. The variables for which the equation has to be solved are also called unknowns, and the values of the unknowns that satisfy the equality are called solutions of the equation. There are two kinds of equations: identities and conditional equations. An identity is true for all values of the variables. A conditional equation is only true for particular values of the variables. An equation is written as two expressions, connected by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
