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Stress Test
Stress testing is a form of deliberately intense or thorough testing, used to determine the stability of a given system, critical infrastructure or entity. It involves testing beyond normal operational capacity, often to a breaking point, in order to observe the results. Reasons can include: * to determine breaking points or safe usage limits * to confirm mathematical model is accurate enough in predicting breaking points or safe usage limits * to confirm intended specifications are being met * to determine modes of failure (how exactly a system fails) * to test stable operation of a part or system outside standard usage Reliability engineers often test items under expected stress or even under accelerated stress in order to determine the operating life of the item or to determine modes of failure.Nelson, Wayne B., (2004), ''Accelerated Testing - Statistical Models, Test Plans, and Data Analysis'', John Wiley & Sons, New York, The term " stress" may have a more specific meani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Failure Cause
Failure causes are defects in design, process, quality, or part application, which are the underlying cause of a failure or which initiate a process which leads to failure. Where failure depends on the user of the product or process, then human error must be considered. Component failure/failure modes A part failure mode is the way in which a component failed "functionally" on the component level. Often a part has only a few failure modes. For example, a relay may fail to open or close contacts on demand. The failure mechanism that caused this can be of many different kinds, and often multiple factors play a role at the same time. They include corrosion, welding of contacts due to an abnormal electric current, return spring fatigue failure, unintended command failure, dust accumulation and blockage of mechanism, etc. Seldom only one cause (hazard) can be identified that creates system failures. The real root causes can in theory in most cases be traced back to some kind of human ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
VO2 Max
V̇O2 max (also maximal oxygen consumption, maximal oxygen uptake or maximal aerobic capacity) is the maximum rate of respiration (physiology), oxygen consumption attainable during physical exertion. The name is derived from three abbreviations: "V̇" for volume (the dot over the V indicates "per unit of time" in Newton's notation), "O2" for oxygen, and "max" for maximum and usually normalized per kilogram of body mass. A similar measure is V̇O2 peak (peak oxygen consumption), which is the measurable value from a session of physical exercise, be it incremental or otherwise. It could match or underestimate the actual V̇O2 max. Confusion between the values in older and popular fitness literature is common. The capacity of the lung to exchange oxygen and carbon dioxide is constrained by the rate of blood#Oxygen transport, blood oxygen transport to active tissue. The measurement of V̇O2 max in the laboratory provides a quantitative value of endurance fitness for comparison of i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Bank Stress Tests
:''This list covers formal bank stress testing programs, as implemented by major regulators worldwide. It does not cover bank proprietary, internal testing programs.'' A bank stress test is an analysis of a bank's ability to endure a hypothetical adverse economic scenario. Stress tests became widely used after the 2008 financial crisis. Example For example, in the U.S. in 2012, an adverse scenario used in stress testing was all of the following: * Unemployment at 13 percent * 50 percent drop in equity prices * 21 percent decline in housing prices. Asia * Monetary Authority of Singapore ** Annual Industry-Wide Stress Testing exercise (usually around Q1) * International Monetary Fund ** 2011 and 2012 stress testing of Japan banks, Financial System Stability Assessment Update (FSAP) * China Banking Regulatory Commission ** 2011 CARPLES risk indicators framework * Australian Prudential Regulation Authority ** 2014 industry stress test * Reserve Bank of New Zealand ** 2014 major bank ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structural Testing
Structural testing is the evaluation of an object (which might be an assembly of objects) to ascertain its characteristics of physical strength. Testing includes evaluating compressive strength, shear strength, tensile strength, all of which may be conducted to failure or to some satisfactory margin of safety. Evaluations may also be indirect, using techniques such as x-ray ultrasound, and ground-penetrating radar, among others, to assess the quality of the object. Structural engineers conduct structural testing to evaluate material suitability for a particular application and to evaluate the capacity of existing structures to withstand foreseeable loads. Items may include buildings (or components), bridges, airplane wings or other types of structures. See also *Structural analysis *Structural load A structural load or structural action is a mechanical load (more generally a force) applied to Structural engineering#Structural elements, structural elements. A load causes s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress Measures
In continuum mechanics, the most commonly used measure of stress is the Cauchy stress tensor, often called simply ''the'' stress tensor or "true stress". However, several alternative measures of stress can be defined: #The Kirchhoff stress (\boldsymbol). #The nominal stress (\boldsymbol). #The Piola–Kirchhoff stress tensors ##The first Piola–Kirchhoff stress (\boldsymbol). This stress tensor is the transpose of the nominal stress (\boldsymbol = \boldsymbol^T). ##The second Piola–Kirchhoff stress or PK2 stress (\boldsymbol). #The Biot stress (\boldsymbol) Definitions Consider the situation shown in the following figure. The following definitions use the notations shown in the figure. In the reference configuration \Omega_0, the outward normal to a surface element d\Gamma_0 is \mathbf \equiv \mathbf_0 and the traction acting on that surface (assuming it deforms like a generic vector belonging to the deformation) is \mathbf_0 leading to a force vector d\mathbf_0. In the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stress (mechanics)
In continuum mechanics, stress is a physical quantity that describes forces present during deformation. For example, an object being pulled apart, such as a stretched elastic band, is subject to ''tensile'' stress and may undergo elongation. An object being pushed together, such as a crumpled sponge, is subject to ''compressive'' stress and may undergo shortening. The greater the force and the smaller the cross-sectional area of the body on which it acts, the greater the stress. Stress has dimension of force per area, with SI units of newtons per square meter (N/m2) or pascal (Pa). Stress expresses the internal forces that neighbouring particles of a continuous material exert on each other, while ''strain'' is the measure of the relative deformation of the material. For example, when a solid vertical bar is supporting an overhead weight, each particle in the bar pushes on the particles immediately below it. When a liquid is in a closed container under pressure, each ... [...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] |
Bioenergetics
Bioenergetics is a field in biochemistry and cell biology that concerns energy flow through living systems. This is an active area of biological research that includes the study of the transformation of energy in living organisms and the study of thousands of different cellular processes such as cellular respiration and the many other metabolic and enzymatic processes that lead to production and utilization of energy in forms such as adenosine triphosphate (ATP) molecules. Nelson, David L., Cox, Michael M. ''Lehninger: Principles of Biochemistry.'' New York: W.H. Freeman and Company, 2013. Sixth ed., pg. 27. That is, the goal of bioenergetics is to describe how living organisms acquire and transform energy in order to perform biological work. Nelson, David L., Cox, Michael M. ''Lehninger: Principles of Biochemistry.'' New York: W.H. Freeman and Company, 2013. Sixth ed., pg. 24. The study of metabolic pathways is thus essential to bioenergetics. Overview Bioenergetics is the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reliability Engineering
Reliability engineering is a sub-discipline of systems engineering that emphasizes the ability of equipment to function without failure. Reliability is defined as the probability that a product, system, or service will perform its intended function adequately for a specified period of time, OR will operate in a defined environment without failure. Reliability is closely related to availability, which is typically described as the ability of a component or system to function at a specified moment or interval of time. The ''reliability function'' is theoretically defined as the probability of success. In practice, it is calculated using different techniques, and its value ranges between 0 and 1, where 0 indicates no probability of success while 1 indicates definite success. This probability is estimated from detailed (physics of failure) analysis, previous data sets, or through reliability testing and reliability modeling. Availability, testability, maintainability, and maintenance ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exercise Physiology
Exercise physiology is the physiology of physical exercise. It is one of the allied health professions, and involves the study of the acute responses and chronic adaptations to exercise. Exercise physiologists are the highest qualified exercise professionals and utilise education, lifestyle intervention and specific forms of exercise to rehabilitate and manage acute and chronic injuries and conditions. Understanding the effect of exercise involves studying specific changes in muscular, cardiovascular, and Neuro-hormonal, neurohormonal Biological system, systems that lead to changes in functional capacity and Physical strength, strength due to endurance training or strength training. The effect of training on the body has been defined as the reaction to the adaptive responses of the body arising from exercise or as "an elevation of metabolism produced by exercise". Exercise physiologists study the effect of exercise on pathology, and the mechanisms by which exercise can reduce or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
