|
Shock Response Spectrum
A Shock Response Spectrum (SRS) Acronym is a graphical representation of a , or any other transient acceleration input, in terms of how a Single Degree Of Freedom (SDOF) system (like a mass on a spring) would respond to that input. The horizontal axis shows the natural frequency of a hypothetical SDOF, and the vertical axis shows the peak acceleration which this SDOF would undergo as a consequence of the shock input.Explanation Explanation Calculation The most direct and intuitive way to generate an SRS from a shock waveform is the following p ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arbitrary SRS Shock
Arbitrariness is the quality of being "determined by chance, whim, or impulse, and not by necessity, reason, or principle". It is also used to refer to a choice made without any specific criterion or restraint. Arbitrary decisions are not necessarily the same as random decisions. For example, during the 1973 oil crisis, Americans were allowed to purchase gasoline only on odd-numbered days if their license plate was odd, and on even-numbered days if their license plate was even. The system was well-defined and not random in its restrictions; however, since license plate numbers are completely unrelated to a person's fitness to purchase gasoline, it was still an arbitrary division of people. Similarly, schoolchildren are often organized by their surname in alphabetical order, a non-random yet an arbitrary method—at least in cases where surnames are irrelevant. Philosophy Arbitrary actions are closely related to teleology, the study of purpose. Actions lacking a ''telos'', a goal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock (mechanics)
In mechanics and physics, shock is a sudden acceleration caused, for example, by impact (mechanics), impact, drop, kick, earthquake, or explosion. Shock is a transient physical excitation. Shock describes matter subject to extreme rates of force with respect to time. Shock is a vector that has units of an acceleration (rate of change of velocity). The unit ''g'' (or ''g'') represents multiples of the standard acceleration of gravity and is conventionally used. A shock pulse can be characterised by its peak acceleration, the duration, and the shape of the shock pulse (half sine, triangular, trapezoidal, etc.). The shock response spectrum is a method for further evaluating a mechanical shock. Shock measurement Shock measurement is of interest in several fields such as *Propagation of heel shock through a runner's body *Measure the magnitude of a shock need to cause damage to an item: fragility. *Measure shock attenuation through athletic flooring *Measuring the effectiveness ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quality Factor
In physics and engineering, the quality factor or factor is a dimensionless parameter that describes how underdamped an oscillator or resonator is. It is defined as the ratio of the initial energy stored in the resonator to the energy lost in one radian of the cycle of oscillation. factor is alternatively defined as the ratio of a resonator's centre frequency to its bandwidth when subject to an oscillating driving force. These two definitions give numerically similar, but not identical, results. Higher indicates a lower rate of energy loss and the oscillations die out more slowly. A pendulum suspended from a high-quality bearing, oscillating in air, has a high , while a pendulum immersed in oil has a low one. Resonators with high quality factors have low damping, so that they ring or vibrate longer. Explanation The factor is a parameter that describes the resonance behavior of an underdamped harmonic oscillator (resonator). Sinusoidally driven resonators having higher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Standard Gravity
The standard acceleration of gravity or standard acceleration of free fall, often called simply standard gravity and denoted by or , is the nominal gravitational acceleration of an object in a vacuum near the surface of the Earth. It is a constant defined by standard as . This value was established by the third General Conference on Weights and Measures (1901, CR 70) and used to define the standard weight of an object as the product of its mass and this nominal acceleration. The acceleration of a body near the surface of the Earth is due to the combined effects of gravity and centrifugal acceleration from the rotation of the Earth (but the latter is small enough to be negligible for most purposes); the total (the apparent gravity) is about 0.5% greater at the poles than at the Equator. Although the symbol is sometimes used for standard gravity, (without a suffix) can also mean the local acceleration due to local gravity and centrifugal acceleration, which varies depending on on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extreme Response Spectrum
{{One source, date=April 2023 The Extreme Response Spectrum (ERS) (or Maximum Response Spectrum (MRS)) is defined as a curve giving the value of the highest peak of the response of a linear Single Degree of Freedom System (SDOF system) to vibration, according to its natural frequency, for a given damping ratio. The response is described here by the relative movement of the mass of this system in relation to its support. The x-axis refers to the natural frequency and the y-axis to the highest peak multiplied by the square of the quantity (2 π x natural frequency), by analogy with the relative displacement shock response spectrum. The severity of a vibration can be evaluated by calculating the stresses on a mathematical or finite element model of the structure and, for example, comparison with the ultimate stress of the material. This is the method used to dimension the structure. Generally, however, the problem is instead to evaluate the relative severity of several vibrations (vibr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fatigue Damage Spectrum
Fatigue is a state of tiredness (which is not sleepiness), exhaustion or loss of energy. It is a symptom of any of various diseases; it is not a disease in itself. Fatigue (in the medical sense) is sometimes associated with medical conditions including autoimmune disease, organ failure, chronic pain conditions, mood disorders, heart disease, infectious diseases, and post-infectious-disease states. However, fatigue is complex and in up to a third of primary care cases no medical or psychiatric diagnosis is found. Fatigue (in the general usage sense of normal tiredness) often follows prolonged physical or mental activity. Physical fatigue results from muscle fatigue brought about by intense physical activity. Mental fatigue results from prolonged periods of cognitive activity which impairs cognitive ability, can manifest as sleepiness, lethargy, or directed attention fatigue, and can also impair physical performance. Definition Fatigue in a medical context is used to cover expe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Data Logger
A shock data logger or vibration data logger is a measurement instrument that is capable of autonomously recording shocks or vibrations over a defined period of time. Digital data is usually in the form of acceleration and time. The shock and vibration data can be retrieved (or transmitted), viewed and evaluated after it has been recorded. In contrast with a shock data logger, a shock detector is used to indicate whether or not the threshold of specified shock has occurred. Functions A logger comprises sensors such as accelerometers, storage media, a processor and power supply. The sensors measure and store shocks either as the entire waveform, summary data, or an indication of whether a threshold value was observed . Some devices have accelerometers built into the unit while others can use external accelerometers. The processor processes the measured data and saves it on the storage media together with the associated measurement times. This allows the measurement data to be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shock Detector
A shock detector, shock indicator, or impact monitor is a device which indicates whether a physical shock or impact has occurred. These usually have a binary output (go/no-go) and are sometimes called ''shock overload devices''. Shock detectors can be used on shipments of fragile valuable items to indicate whether a potentially damaging drop or impact may have occurred. They are also used in sports helmets to help estimate if a dangerous impact may have occurred.Harris, C. M., and Peirsol, A. G. "Shock and Vibration Handbook", 2001, McGraw Hill, ISBN 0-07-137081-1 By contrast, a shock data logger is a data acquisition system for analysis and recording of shock pulses. Overview Shocks and impacts are often specified by the peak acceleration expressed in g-s (sometimes called g-forces). The form of the shock pulse and particularly the duration are equally important. For example, a short 1 ms 300 g shock has little damage potential and is not usually of interest but a 20 ms 30 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MIL-STD-810
MIL-STD-810, U.S. Department of Defense Test Method Standard, Environmental Engineering Considerations and Laboratory Tests, is a United States Military Standard that specifies environmental tests to determine whether equipment is suitably designed to survive the conditions that it would experience throughout its service life. The standard establishes chamber test methods that replicate the effects of environments on the equipment rather than imitating the environments themselves. Although prepared specifically for U.S. military applications, the standard is often applied for commercial products as well. The standard's guidance and test methods are intended to: * define environmental stress sequences, durations, and levels of equipment life cycles; * be used to develop analysis and test criteria tailored to the equipment and its environmental life cycle; * evaluate equipment's performance when exposed to a life cycle of environmental stresses * identify deficiencies, shortcomings ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
