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Analogue systems and concepts
Published in Geoff Lewis, Communications Technology Handbook, 2013
Slew rate and full power response/bandwidth. An operational amplifier responds to high level signals somewhat slower than small signals. This is due to the circuit capacitances that require time to change their state of charge. For this reason the full power bandwidth is not likely to exceed about 4 MHz. The slew rate defines the maximum rate of change of output voltage for a large step input signal and is typically greater than 50 V/μS. If this rate is exceeded by too large a driving signal, then distortion results. The relationship between full power bandwidth and slew rate is given by: fm=slew rate/(2π/Vout.max)
Introduction to Vibrations
Published in Ramin S. Esfandiari, Bei Lu, Modeling and Analysis of Dynamic Systems, 2018
In the half-power bandwidth method, the frequency response of the system is measured. The damping ratio ζ is estimated using a peak in the magnitude curve of the frequency response and two half-power points, which are 3 dB down from the peak. The value of the damping ratio ζ is given by ζ≈ω2−ω12ωn
Evaluation of the functioning of rubber isolators of the elementary school “Pestalozzi” under strong earthquake effects
Published in Kosta Talaganov, Gunther Schmid, Computational Structural Dynamics, 2020
To define the damping coefficients, two methods were used: half-power bandwidth (frequency-response) method andlogarithmic decrement (time-response) method.
Manufacturing and damping properties of microflake–nanoflake reinforced carbon fiber epoxy resin matrix composites
Published in Mechanics of Advanced Materials and Structures, 2023
Xiaowen Dong, Ao Li, Yangyang Yan
Figure 3 shows the structural vibration experimental system, which is mainly composed of PCB 086C01 modal force hammer, PCB 352C22 lightweight acceleration sensor, LMS 8-channel data acquisition instrument, and mobile workstation. The sensors have been calibrated during the experiment, and many pre-experiments have been carried out before the formal test to ensure the repeatability and effectiveness of the test data. The tested plate specimen is clamped by a fixed fixture at one side. In the vibration test, the modal force hammer is used to impulse the structure, and the vibration response signal is obtained through the lightweight acceleration sensor. Based on the frequency response function data, the first-order damping ratio of the CFRP plate is obtained through the half-power bandwidth method. To study the influence of the content of flake polyurethane fillers on the damping property of CFRP, the damping property of samples with different content of flake polyurethane fillers is tested by the hammering method. The hammer is used to knock three times at the striking point, and the average value of the three times data is taken as the damping value of CFRP.
Experimental and numerical analysis of different natural fiber polymer composite
Published in Materials and Manufacturing Processes, 2023
Savendra Pratap Singh, Akriti Dutt, Chetan Kumar Hirwani
Harmonic analysis of 15% coir epoxy, 15% bamboo epoxy and 15% hemp epoxy composite has been performed using ANSYS 2021 R1 for the calculation of damping factor. The obtained frequency deformation response has been shown in Figure 7, 8 and 9 for 15% hemp epoxy composite, 15% bamboo epoxy composite and 15% coir epoxy composite. Damping factor has been calculated by using half power bandwidth method as explained earlier. For 15% hemp fiber composite, from Figure 7 frequency response also known as bode plot reveals that there are four peaks found and corresponding damping factor values predicted using half power bandwidth method. It can be stated that with increase in the value of natural frequency damping factor decreases. Similarly, four peaks are found for 15% bamboo composite and 15% coir composite as shown in Figures 8 and 9, respectively. Here, peaks indicated the phenomenon of resonance so while working with composite it must be avoided otherwise amplitude may go higher causes failure of composite. The natural frequency and damping factor values in case of hemp fiber are better than bamboo and coir fiber composite. The worst results are obtained for coir fiber composite.
Nonlinear dynamic analysis of a reciprocative magnetic coupling on performance of piezoelectric energy harvester interfaced with DC circuit
Published in Mechanics of Advanced Materials and Structures, 2022
Dauda Sh. Ibrahim, Sun Beibei, Orelaja Adewale Oluseyi, Zhao Peng, Umer Sharif
Here, is the open circuit resonance frequency corresponding to the amplitude of a voltage when PZT is connected to a resistance load (R) of infinity ( value. The parameter is determined based on the concept of half-power bandwidth which is the frequency bandwidth at a point where the maximum voltage value equals [40], and ξp is the mechanical damping constant of the piezoelectric material. Therefore, in order to obtain the open circuit resonant frequency, the short circuit resonant frequency as well as the half-power frequency bandwidth required for calculating Ceq1, frequency response analysis of the harvester is conducted in an FEA software namely; COMSOL Multiphysics.