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Paris' Law
Paris' law (also known as the Paris–Erdogan equation) is a crack growth equation that gives the rate of growth of a fatigue (material), fatigue crack. The stress intensity factor K characterises the load around a crack tip and the rate of crack growth is experimentally shown to be a function of the range of stress intensity \Delta K seen in a loading cycle. The Paris equation is :\begin &= C\left(\Delta K\right)^, \end where a is the crack length and a/N is the fatigue crack growth for a load cycle N. The material coefficients C and m are obtained experimentally and also depend on environment, frequency, temperature and stress ratio. The stress intensity factor range has been found to correlate the rate of crack growth from a variety of different conditions and is the difference between the maximum and minimum stress intensity factors in a load cycle and is defined as : \Delta K= K_-K_. Being a power law relationship between the crack growth rate during cyclic loadin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crack Propagation Curve Paris' Law
Crack frequently refers to: * Crack, a fracture in a body * Crack, a fracture (geology) in a rock * Crack, short for crack cocaine Crack(s) or The Crack may also refer to: Arts, entertainment, and media * ''The Crack'', first album by The Ruts * Crack (album), ''Crack'' (album), an album by Z-RO * Crack (band), a Spanish progressive rock group * The Crack (magazine), ''The Crack'' (magazine), a free culture magazine covering the North East of England * Crack (magazine), ''Crack'' (magazine), a UK-based European music and culture monthly * Crack Movement, a Mexican literary movement * Cracks (album), ''Cracks'' (album), an album by Nabiha * Cracks (film), ''Cracks'' (film), a 2009 independent thriller Software * Crack (password software), a UNIX/Linux password hacking program for systems administrators * Software cracking, a computer program that modifies other software to remove or disable features usually related to digital rights management * No-disc crack, software to circum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crack Growth Equation
A crack growth equation is used for calculating the size of a fatigue (material), fatigue crack growing from cyclic loads. The growth of a fatigue crack can result in catastrophic failure, particularly in the case of aircraft. When many growing fatigue cracks interact with one another it is known as widespread fatigue damage. A crack growth equation can be used to ensure safety, both in the design phase and during operation, by predicting the size of cracks. In critical structure, loads can be recorded and used to predict the size of cracks to ensure maintenance or retirement occurs prior to any of the cracks failing. Safety factors are used to reduce the predicted fatigue life to a service fatigue life because of the sensitivity of the fatigue life to the size and shape of crack initiating defects and the variability between assumed loading and actual loading experienced by a component. ''Fatigue life'' can be divided into an initiation period and a crack growth period. Crack gro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatigue (material)
In materials science, fatigue is the initiation and propagation of cracks in a material due to cyclic loading. Once a fatigue crack has initiated, it grows a small amount with each loading cycle, typically producing striations on some parts of the fracture surface. The crack will continue to grow until it reaches a critical size, which occurs when the stress intensity factor of the crack exceeds the fracture toughness of the material, producing rapid propagation and typically complete fracture of the structure. 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. Most materials, such as composites, plastics and ceramics, seem to experience some sort of fatigue-related failure. To aid in predicting the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress Intensity Factor
In fracture mechanics, the stress intensity factor () is used to predict the Stress (mechanics), stress state ("stress intensity") near the tip of a Fracture, crack or Notch (engineering), notch caused by a remote load or residual stresses. It is a theoretical construct usually applied to a homogeneous, linear Elasticity (physics), elastic material and is useful for providing a Material failure theory, failure criterion for Brittleness, brittle materials, and is a critical technique in the discipline of damage tolerance. The concept can also be applied to materials that exhibit ''small-scale yield (engineering), yielding'' at a crack tip. The magnitude of depends on specimen geometry, the size and location of the crack or notch, and the magnitude and the distribution of loads on the material. It can be written as: :K = \sigma \sqrt \, f(a/W) where f(a/W) is a specimen geometry dependent function of the crack length, , and the specimen width, , and is the applied stress. Lin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Plymouth
The University of Plymouth is a public research university based predominantly in Plymouth, England, where the main campus is located, but the university has campuses and affiliated colleges across South West England. With students, it is the List of universities in the United Kingdom by enrollment, largest in the United Kingdom by total number of students (including the Open University). History 1862 – 2000 The university was originally founded as thPlymouth School of Navigation in 1862, before becoming a university college in 1920 and a polytechnic (United Kingdom), polytechnic institute in 1970, with its constituent bodies being Plymouth Polytechnic, Rolle College in Exmouth, the Exeter College of Art and Design (which were, before April 1989, run by Devon County Council) and Seale-Hayne College (which before April 1989 was an independent charity). It was renamed Polytechnic South West in 1989, a move that was unpopular with students as the name lacked identity. It was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Law
In statistics, a power law is a Function (mathematics), functional relationship between two quantities, where a Relative change and difference, relative change in one quantity results in a relative change in the other quantity proportional to the change raised to a constant exponent: one quantity varies as a power of another. The change is independent of the initial size of those quantities. For instance, the area of a square has a power law relationship with the length of its side, since if the length is doubled, the area is multiplied by 2, while if the length is tripled, the area is multiplied by 3, and so on. Empirical examples The distributions of a wide variety of physical, biological, and human-made phenomena approximately follow a power law over a wide range of magnitudes: these include the sizes of craters on the moon and of solar flares, cloud sizes, the foraging pattern of various species, the sizes of activity patterns of neuronal populations, the frequencies of words ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
X-axis
In geometry, a Cartesian coordinate system (, ) in a plane is a coordinate system that specifies each point uniquely by a pair of real numbers called ''coordinates'', which are the signed distances to the point from two fixed perpendicular oriented lines, called '' coordinate lines'', ''coordinate axes'' or just ''axes'' (plural of ''axis'') of the system. The point where the axes meet is called the '' origin'' and has as coordinates. The axes directions represent an orthogonal basis. The combination of origin and basis forms a coordinate frame called the Cartesian frame. Similarly, the position of any point in three-dimensional space can be specified by three ''Cartesian coordinates'', which are the signed distances from the point to three mutually perpendicular planes. More generally, Cartesian coordinates specify the point in an -dimensional Euclidean space for any dimension . These coordinates are the signed distances from the point to mutually perpendicular fixed h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rainflow-counting Algorithm
The rainflow-counting algorithm is used in calculating the fatigue (material), fatigue life of a component in order to convert a loading sequence of varying stress (physics), stress into a set of constant amplitude stress reversals with equivalent fatigue damage. The method successively extracts the smaller interruption cycles from a sequence, which models the material memory effect seen with stress-strain hysteresis cycles. This simplification allows the number of cycles until failure of a component to be determined for each rainflow cycle using either Fatigue (material)#Miner's rule, Miner's rule to calculate the ''fatigue damage'', or in a crack growth equation to calculate the crack increments. Both methods give an estimate of the ''fatigue life'' of a component. In cases of multiaxial loading, critical plane analysis can be used together with rainflow counting to identify the uniaxial history associated with the plane that maximizes damage. The algorithm was developed by Tatsu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul C
Paul C. McKasty (September 20, 1964July 17, 1989), better known as Paul C, was an American East Coast hip hop pioneer, producer, engineer, and mixer in the 1980s.Pritt Kalsi McKasty gained recognition for his work with notable artists such as Devo, Organized Konfusion, Kwamé, Queen Latifah, Biz Markie, Ultramagnetic MCs, Rahzel, and Eric B & Rakim. ''Complex'' called him "one of the most important figures in the development of sampling" and Questlove of the Roots called McKasty, "damn near the J Dilla of his day." Work Paul gave himself the middle name "Charles" after Ray Charles, which he shortened to the initial "C". He developed an interest in music from his older brother Michael, who was a guitarist, and Tim, who worked as a recording engineer at 1212 Studio in Queens. According to Paul's middle school friend TeQnotic, he was an already gifted artist and bass guitar player in junior high. McKasty began his musical career as a bassist of the pop rock band the Mandolindle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crack Closure
Crack closure is a phenomenon in fatigue loading, where the opposing faces of a crack remain in contact even with an external load acting on the material. As the load is increased, a critical value will be reached at which time the crack becomes ''open''. Crack closure occurs from the presence of material propping open the crack faces and can arise from many sources including plastic deformation or phase transformation during crack propagation, corrosion of crack surfaces, presence of fluids in the crack, or roughness at cracked surfaces. Description During cyclic loading, a crack will open and close causing the crack tip opening displacement (CTOD) to vary cyclically in phase with the applied force. If the loading cycle includes a period of negative force or stress ratio R (i.e. R < 0), the CTOD will remain equal to zero as the crack faces are pressed together. However, it was discovered that the CTOD can also be zero at other times even when the applied force is positi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fracture Toughness
In materials science, fracture toughness is the critical stress intensity factor of a sharp Fracture, crack where propagation of the crack suddenly becomes rapid and unlimited. It is a material property that quantifies its ability to resist crack propagation and failure under applied stress. A component's thickness affects the constraint conditions at the tip of a crack with thin components having plane stress conditions, leading to ductile behavior and thick components having plane strain conditions, where the constraint increases, leading to brittle failure. Plane strain conditions give the lowest fracture toughness value which is a material properties, material property. The critical value of stress intensity factor in Fracture mechanics, mode I loading measured under plane strain conditions is known as the plane strain fracture toughness, denoted K_\text. When a test fails to meet the thickness and other test requirements that are in place to ensure plane strain conditions, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
