A Short Note on Synchrosqueezed Transforms for Resonant Capture, Sommerfeld Effect and Nonlinear Jump Characterization in Mechanical Systems

2021 ◽  
Author(s):  
Marcus Varanis ◽  
Anderson Langone Silva ◽  
José Manoel Balthazar ◽  
Clivaldo Oliveira ◽  
Angelo Tusset ◽  
...  
Keyword(s):  
Short Note ◽  
Mechanical Systems ◽  
Sommerfeld Effect

A Short Note on Transverse Vibrations of a Shaft Carrying Two (or One) Disk Excited by a Nonideal Motor

2008 ◽  
Vol 4 (1) ◽  
Author(s):  
J. L. Palacios Felix ◽  
J. M. Balthazar ◽  
R. M. L. R. F. Brasil
Keyword(s):  
Resonance Frequency ◽  
Power Supply ◽  
Electric Motor ◽  
Rotational Velocity ◽  
Dynamical Behavior ◽  
Short Note ◽  
Sommerfeld Effect ◽  
Jump Phenomenon ◽  
Transverse Vibrations ◽  
Limited Power

The paper presents a number of numerical simulations of the transverse vibrations of two (or one) unbalanced rotors forced by an electric motor, with limited power supply, during the passage through of the two resonance zones (increasing and decreasing input voltages). The predominant presence of the Sommerfeld effect, when the rotational velocity of the motor is captured, in the second resonance frequency is demonstrated. We have shown that the hysteretic jump phenomenon exists in a rotor system with two (or one) disks, and with this, we have shown that a torque is influenced by the dynamical behavior of the rotor.

scholarly journals Remarks on the Sommerfeld effect characterization in the wavelet domain

2018 ◽  
Vol 25 (1) ◽  
pp. 98-108 ◽  
Author(s):  
M. Varanis ◽  
J.M. Balthazar ◽  
A. Silva ◽  
A.G. Mereles ◽  
R. Pederiva
Keyword(s):  
Energy Source ◽  
Wavelet Transform ◽  
Mechanical System ◽  
Wavelet Packet ◽  
Mechanical Systems ◽  
Wavelet Domain ◽  
Sommerfeld Effect ◽  
Nonstationary Regime ◽  
Shear Building

In many applications in engineering, a mechanical system operates in the nonstationary regime, either partially of fully, creating the possibility to generate nonlinearities in them. Great efforts have been made to better understand and characterize these phenomena. One of several methods that are being used for the processing of signals of a nonstationary nature, as well as for the characterization of nonlinearities in mechanical systems, is the wavelet transform. A particular phenomenon that is seen in systems operating in the nonstationary regime is the Sommerfeld effect, which occurs due to the nonlinear interaction between a nonideal energy source and a mechanical system. This phenomenon can lead to high amplitudes of vibration for the system that in turn can cause damage in it. Therefore, this work presents an application of the continuous wavelet transform and the wavelet packet transform for the characterization of the Sommerfeld effect in mechanical systems where only the time response is at hand. Experimental procedures were performed where a nonideal energy source (an unbalanced DC motor) was used to excite (a) a portal frame and (b) a three-story shear-building. The results showed the effectiveness and the potential of the methods proposed.

Introduction

2018 ◽  
Author(s):  
Peter Hopkins
Keyword(s):  
Final Section ◽  
Short Note ◽  
Current Situation ◽  
Research Projects ◽  
Everyday Lives ◽  
Early Settlement ◽  
The Everyday ◽  
Initial Research

The chapters in this collection explore the everyday lives, experiences, practices and attitudes of Muslims in Scotland. In order to set the context for these chapters, in this introduction I explore the early settlement of Muslims in Scotland and discuss some of the initial research projects that charted the settlement of Asians and Pakistanis in Scotland’s main cities. I then discuss the current situation for Muslims in Scotland through data from the 2011 Scottish Census. Following a short note about the significance of the Scottish context, in the final section, the main themes and issues that have been explored in research about Muslims in Scotland.

Phase space of mechanical systems with a gauge group

1991 ◽  
Vol 161 (2) ◽  
pp. 13-75 ◽  
Author(s):  
Lev V. Prokhorov ◽  
Sergei V. Shabanov
Keyword(s):  
Phase Space ◽  
Gauge Group ◽  
Mechanical Systems

EVALUATION OF MECHANICAL SYSTEMS USED IN PERFUSION

1972 ◽  
Vol 68 (2_Supplb) ◽  
pp. S44-S73 ◽  
Author(s):  
Eugene F. Bernstein
Keyword(s):  
Mechanical Systems ◽  
Organ Perfusion ◽  
Critical Factors ◽  
System 2 ◽  
Common Problems ◽  
Mechanical Components ◽  
Perfusion Experiment ◽  
Selection Of

ABSTRACT Among the critical factors in organ perfusion are (1) the mechanical components of the system, (2) the composition of the perfusate, and (3) the perfusing conditions. In this review, particular consideration is given to the pump, the oxygenator, and cannulas in such systems. Emphasis is placed upon the selection of pertinent equipment for the goals of a particular perfusion experiment, based upon the criteria of adequacy of the perfusion. Common problems in organ perfusion are summarized, and potential solutions to the perfusion problem, involving either biologic or mechanical extracorporeal systems, are suggested.

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