Minimizing the Effect of Out of Bandwidth Modes in Truncated Structure Models

1998 ◽  
Vol 122 (1) ◽  
pp. 237-239 ◽  
Author(s):  
S. O. Reza Moheimani
Keyword(s):  
Modal Analysis ◽  
Low Frequency ◽  
Control Design ◽  
Higher Order ◽  
Analysis Approach ◽  
Order Model ◽  
Infinite Dimensional ◽  
Higher Order Modes ◽  
Frequency Term ◽  
Zero Frequency

The modal analysis approach to modeling of structures and acoustic systems results in infinite-dimensional models. For control design purposes, these models are simplified by removing higher frequency modes which lie out of the bandwidth of interest. Truncation can considerably perturb the in-bandwidth zeros of the truncated model. This paper suggests a method of minimizing the effect of the removed higher order modes on the low frequency dynamics of the truncated model by adding a zero frequency term to the low order model of the system. [S0022-0434(00)01501-X]

Modal Analysis of Multi Layer Viscoelastic Rotors Considering Higher Order Model

2013 ◽  
Author(s):  
S. Chandraker ◽  
H. Roy ◽  
G. Maurya
Keyword(s):  
Modal Analysis ◽  
Equations Of Motion ◽  
Stability Limit ◽  
Higher Order ◽  
Constitutive Relationship ◽  
Order System ◽  
Order Model ◽  
Rotor Shaft ◽  
Number Of Layers ◽  
Modal Damping

This paper involves the development of mathematical model of multilayered viscoelastic rotor using beam finite element and at the same time studying their modal analysis. The operator based constitutive relationship is used to obtain the equations of motion. The FE formulation contents higher order system where the number of order increases with the number of layers exists in the rotor shaft. Under these conditions, the complex modal behaviour of the rotor-shaft is studied to get an insight of the dynamic characteristics of the system, in terms of Modal Damping Factors, Stability Limit of Spin-speed (SLS), the directional Frequency Response Function (dFRF) as well as the direction of whirl of the shaft in different modes. Many researchers adopted this methodology for obtaining the dynamic behaviour of a second order system. This work is started by motivation of the absentia of work for higher order system.

Polarization and modal analysis of a large-area, polarization-maintaining higher-order-modes fiber via a Bragg grating

2020 ◽  
Vol 45 (2) ◽  
pp. 403
Author(s):  
Raja Ahmad ◽  
Paul S. Westbrook ◽  
Kazi S. Abedin ◽  
Jeffrey W. Nicholson ◽  
Man F. Yan ◽  
...  
Keyword(s):  
Modal Analysis ◽  
Higher Order ◽  
Bragg Grating ◽  
Large Area ◽  
Higher Order Modes ◽  
Polarization Maintaining

Lumped Element Multimode Modeling of Balanced-Armature Receiver Using Modal Analysis

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Wei Sun ◽  
Wenxiang Hu
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Frequency Domain ◽  
Higher Order ◽  
Numerical Results ◽  
Fe Model ◽  
Lumped Element ◽  
Higher Order Modes ◽  
Mode Decomposition ◽  
Multimode Model

For the lack of higher-order modes, lumped element (LE) models currently used may be insufficient to predict the system of balanced-armature receiver (BAR). We develop an LE multimode model for BAR in the frequency domain based on the techniques of mode decomposition, truncation, and selection. The validation is made by comparing with both the corresponding combined finite element (FE)–LE model and the full FE model. Numerical results prove that the developed model is not only as effective as the combined FE–LE model but also much more efficient. Additionally, an in-depth investigation performed discloses the inherent deficiency of the traditional LE model.

Testing a Higher-Order Model of Psychological Resilience in Recruits

2010 ◽  
Author(s):  
Donald R. McCreary ◽  
Jennifer E. C. Lee ◽  
Kerry A. Sudom
Keyword(s):  
Higher Order ◽  
Psychological Resilience ◽  
Order Model

scholarly journals Electrical characterisation of higher order spin wave modes in vortex-based magnetic tunnel junctions

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Alex. S. Jenkins ◽  
Lara San Emeterio Alvarez ◽  
Samh Memshawy ◽  
Paolo Bortolotti ◽  
Vincent Cros ◽  
...  
Keyword(s):  
Spin Wave ◽  
Tunnel Junctions ◽  
Magnetic Tunnel Junctions ◽  
Higher Order ◽  
Spin Torque ◽  
Micromagnetic Simulations ◽  
Higher Order Modes ◽  
Spin Diode ◽  
Super High Frequency ◽  
Wave Modes

AbstractNiFe-based vortex spin-torque nano-oscillators (STNO) have been shown to be rich dynamic systems which can operate as efficient frequency generators and detectors, but with a limitation in frequency determined by the gyrotropic frequency, typically sub-GHz. In this report, we present a detailed analysis of the nature of the higher order spin wave modes which exist in the Super High Frequency range (3–30 GHz). This is achieved via micromagnetic simulations and electrical characterisation in magnetic tunnel junctions, both directly via the spin-diode effect and indirectly via the measurement of the coupling with the gyrotropic critical current. The excitation mechanism and spatial profile of the modes are shown to have a complex dependence on the vortex core position. Additionally, the inter-mode coupling between the fundamental gyrotropic mode and the higher order modes is shown to reduce or enhance the effective damping depending upon the sense of propagation of the confined spin wave.

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