scholarly journals Sine Sweep and Steady-State Response of a Simplified Solar Array Model With Nonlinear Support

Author(s):  
Rob H. B. Fey ◽  
Berend Winter ◽  
Jaap J. Wijker

Abstract In this paper the dynamic behaviour of a multi degree of freedom beam model of a solar array structure is investigated both experimentally and numerically. The beam is supported by one nonlinear element, a so-called snubber. This snubber can only take compressive forces. Two types of excitation are applied and compared: sine sweep excitation (with different sweep rates and directions) and steady-state excitation. Emphasis lies on the investigation of the dynamic behaviour of the system under prestress, which implies softening behaviour at the time when snubber and beam loose contact. The system displays rich nonlinear dynamic behaviour: multiple solutions (hysteresis loop), superharmonic resonances and subharmonic, quasi-periodic and chaotic solutions. Good correspondence between experimental and numerical results has been found.

2000 ◽  
Vol 122 (4) ◽  
pp. 437-442
Author(s):  
Shigeru Aoki ◽  
Takeshi Watanabe

This paper deals with steady-state response of the piping system with nonlinear support having hysteresis damping characteristics. Considering the energy loss for contact with a support, an analytical method of approximate solution for the beam, a one-span model of the piping system, with quadrilateral hysteresis loop characteristics is presented. Some numerical results of the approximate solution for the response curves and the mode shapes are shown. [S0094-9930(00)00204-3]


2002 ◽  
Vol 13 (05) ◽  
pp. 260-269 ◽  
Author(s):  
Barbara Cone-Wesson ◽  
John Parker ◽  
Nina Swiderski ◽  
Field Rickards

Two studies were aimed at developing the auditory steady-state response (ASSR) for universal newborn hearing screening. First, neonates who had passed auditory brainstem response, transient evoked otoacoustic emission, and distortion-product otoacoustic emission tests were also tested with ASSRs using modulated tones that varied in frequency and level. Pass rates were highest (> 90%) for amplitude-modulated tones presented at levels ≥ 69 dB SPL. The effect of modulation frequency on ASSR for 500- and 2000-Hz tones was evaluated in full-term and premature infants in the second study. Full-term infants had higher pass rates for 2000-Hz tones amplitude modulated at 74 to 106 Hz compared with pass rates for a 500-Hz tone modulated at 58 to 90 Hz. Premature infants had lower pass rates than full-term infants for both carrier frequencies. Systematic investigation of ASSR threshold and the effect of modulation frequency in neonates is needed to adapt the technique for screening.


2021 ◽  
Vol 11 (4) ◽  
pp. 1717
Author(s):  
Gilberto Gonzalez Avalos ◽  
Noe Barrera Gallegos ◽  
Gerardo Ayala-Jaimes ◽  
Aaron Padilla Garcia

The direct determination of the steady state response for linear time invariant (LTI) systems modeled by multibond graphs is presented. Firstly, a multiport junction structure of a multibond graph in an integral causality assignment (MBGI) to get the state space of the system is introduced. By assigning a derivative causality to the multiport storage elements, the multibond graph in a derivative causality (MBGD) is proposed. Based on this MBGD, a theorem to obtain the steady state response is presented. Two case studies to get the steady state of the state variables are applied. Both cases are modeled by multibond graphs, and the symbolic determination of the steady state is obtained. The simulation results using the 20-SIM software are numerically verified.


2020 ◽  
pp. 155005942098270
Author(s):  
Sarah Ahmed ◽  
Jennifer R. Lepock ◽  
Romina Mizrahi ◽  
R. Michael Bagby ◽  
Cory J. Gerritsen ◽  
...  

Aim Deficits in synchronous, gamma-frequency neural oscillations may contribute to schizophrenia patients’ real-world functional impairment and can be measured electroencephalographically using the auditory steady-state response (ASSR). Gamma ASSR deficits have been reported in schizophrenia patients and individuals at clinical high risk (CHR) for developing psychosis. We hypothesized that, in CHR patients, gamma ASSR would correlate with real-world functioning, consistent with a role for gamma synchrony deficits in functional impairment. Methods A total of 35 CHR patients rated on Global Functioning: Social and Role scales had EEG recorded while listening to 1-ms, 93-dB clicks presented at 40 Hz in 500-ms trains, in response to which 40-Hz evoked power and intertrial phase-locking factor (PLF) were measured. Results In CHR patients, lower 40-Hz PLF correlated with lower social functioning. Conclusions Gamma synchrony deficits may be a biomarker of real-world impairment at early stages of the schizophrenia disease trajectory.


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