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Wireless Coding and Modulation
Published in Mahbub Hassan, Wireless and Mobile Networking, 2022
Figure 2 illustrates the frequency, amplitude, and phase of a sine wave. Amplitude is the height of the wave, measured from zero to the maximum value, either up or down. Note that the sine wave is cyclic, i.e., it keeps repeating the pattern. One complete pattern is called a cycle.
Introduction
Published in James P. Kohn, The Ergonomic Casebook, 2020
James Kohn, Celeste Winterberger
Typically, segmental vibration is caused by hand-held power instruments such as chain saws, jackhammers, drills, and torque guns (Tsimberov, 1994). Additionally, when safety professionals deal with vibration, they must understand the concepts of resonance and damping. Resonance occurs at a frequency where an object will vibrate at its maximum amplitude which is greater than the amplitude of the original vibration. In essence, the object will act as a magnifier at resonance frequencies.
Dynamics of linear elastic SDOF oscillators
Published in Mark Aschheim, Enrique Hernández-Montes, Dimitrios Vamvatsikos, Design of Reinforced Concrete Buildings for Seismic Performance, 2019
Mark Aschheim, Enrique Hernández, Dimitrios Vamvatsikos
Resonance is the tendency of a system to oscillate with large peak amplitude under forced vibration at particular frequencies, known as the system’s resonant frequencies. Resonance occurs for an undamped SDOF system if the system’s natural frequency (ω) coincides with the frequency of harmonic loading (i.e., Ω = ω). Response amplitudes approach infinity for undamped systems, but practically speaking, as the amplitude increases a point will be reached where the physical properties of the system change, thus creating a nonlinear problem. For damped SDOF systems, resonance occurs at frequencies Ω slightly less than ω, as can be observed in Figure 3.4. While damping causes a reduction in peak response amplitudes relative to the undamped case (e.g., Figure 3.4), resonant amplitudes can still be quite large, compared with other cases of forced vibration.
Online condition monitoring system for rotating machine elements using edge computing
Published in Australian Journal of Mechanical Engineering, 2023
N. D. Pagar, S. S. Gawde, S. B. Sanap
Vibration measurement has three characteristics namely: Amplitude, Frequency and Time. Amplitude is a measure of the amount of movement, which is in turn related to the severity of the vibration. Amplitude measurement corresponds to measuring displacement, velocity or acceleration, depending on user’s criteria. The term ‘frequency’ refers to the number of times that a movement takes place. It identifies the source of the vibration. It is possible to establish an analytical connection between the units of displacement, velocity, and acceleration, which together make up the amplitude, and the frequency of any periodic signal. The direction in which the movement is taking place is indicated by the phase. It gives us the ability to evaluate the relative movement of different areas on a machine and compare how they move.
Reflection of plane waves in a nonlocal microstretch thermoelastic medium with temperature dependent properties under three-phase-lag model
Published in Mechanics of Advanced Materials and Structures, 2022
Sunita Deswal, Devender Sheoran, Seema Thakran, Kapil Kumar Kalkal
Figure 8 depicts the variation of modulus of energy ratios of various reflected waves and their sum against angle of incidence of coupled longitudinal wave vibrating with speed It can be seen from the plot that the values of and sum are almost same and equal to 1.0 and the values of are very small as the amplitude ratios were found to be small. These energy ratios have been shown by curves III, IV, V and VI in the figure after multiplying their original values by the factors respectively. It can be observed from this figure that energy carried out by reflected coupled longitudinal wave propagating with speed is maximum in comparison to the energy carried by other reflected waves. This is physically true as the energy ratios are proportional to the square of the corresponding amplitude ratios. Also, it has been validated that the sum of energy ratios is approximately equal to unity, at each angle of incidence. This shows that there is no dissipation of energy during reflection phenomenon.
Waves in a nonlocal micropolar thermoelastic half-space with voids under dual-phase-lag model
Published in Waves in Random and Complex Media, 2021
Ramesh Kumar, Devender Sheoran, Seema Thakran, Kapil Kumar Kalkal
Figure 6 depicts the variation of modulus of energy ratios of various reflected waves and their sum against angle of incidence of coupled longitudinal displacement wave vibrating with speed . It can be seen from the plot that the values of and sum are almost same (equal to 1.0) and the values of are very small as the amplitude ratios were found to be very small. These energy ratios have been shown by curves III, IV, V and VI in the figure after multiplying their original values by the factors respectively. It can be observed from this figure that energy carried by reflected coupled longitudinal displacement wave propagating with speed is maximum in comparison to the energy carried by other reflected waves. This is physically true as the energy ratios are proportional to the square of the corresponding amplitude ratios. Also, it has been validated that the sum of energy ratios is approximately equal to unity. This shows that there is no dissipation of energy during reflection phenomenon.