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.

Contribution of Lamb wave modes in the formation of higher order modes cluster (HOMC) guided waves

2021 ◽  
pp. 095440622110424
Author(s):  
Z Abbasi ◽  
F Honarvar
Keyword(s):  
Finite Element ◽  
Wave Packet ◽  
Lamb Wave ◽  
Guided Waves ◽  
Element Model ◽  
Higher Order ◽  
Guided Wave ◽  
Cross Sectional ◽  
Higher Order Modes ◽  
Wave Modes

In recent years, Higher Order Modes Cluster (HOMC) guided waves have been considered for ultrasonic testing of plates and pipes. HOMC guided waves consist of higher order Lamb wave modes that travel together as a single nondispersive wave packet. The objective of this paper is to investigate the effect of frequency-thickness value on the contribution of Lamb wave modes in an HOMC guided wave. This is an important issue that has not been thoroughly investigated before. The contribution of each Lamb wave mode in an HOMC guided wave is studied by using a two-dimensional finite element model. The level of contribution of various Lamb wave modes to the wave cluster is verified by using a 2D FFT analysis. The results show that by increasing the frequency-thickness value, the order of contributing modes in the HOMC wave packet increases. The number of modes that comprise a cluster also increases up to a specific frequency-thickness value and then it starts to decrease. Plotting of the cross-sectional displacement patterns along the HOMC guided wave paths confirms the shifting of dominant modes from lower to higher order modes with increase of frequency-thickness value. Experimental measurements conducted on a mild steel plate are used to verify the finite element simulations. The experimental results are found to be in good agreement with simulations and confirm the changes observed in the level of contribution of Lamb wave modes in a wave cluster by changing the frequency-thickness value.

Nonlinear finite element analysis of smart laminated composite sandwich plates

2014 ◽  
Vol 14 (03) ◽  
pp. 1350075 ◽  
Author(s):  
S. K. Sarangi ◽  
B. Basa
Keyword(s):  
Finite Element ◽  
Fiber Composite ◽  
Orientation Angle ◽  
Shear Deformation Theory ◽  
Laminated Composite ◽  
Numerical Results ◽  
Sandwich Plates ◽  
Fe Model ◽  
Composite Sandwich ◽  
Composite Sandwich Plates

This paper deals with the nonlinear dynamic analysis of smart laminated composite sandwich plates. A three dimensional energy based finite element (FE) model has been developed for the composite sandwich plates integrated with the patches of active constrained layer damping (ACLD) treatment. Von Kármán type nonlinear strain–displacement relations and the first-order shear deformation theory (FSDT) are adopted individually for each layer of the sandwich plate in developing the FE model. The constraining layer of the ACLD treatment is considered to be made of active fiber composite (AFC) material. The Golla–Hughes–McTavish (GHM) method is used to model the constrained viscoelastic layer of the ACLD treatment in the time domain. Sandwich plates with symmetric and antisymmetric laminated faces separated by HEREX core are considered for evaluation of the numerical results. The numerical results indicate that the ACLD patches significantly improve the damping characteristics of the composite sandwich plates for suppressing their geometrically nonlinear transient vibrations. The effect of variation of piezoelectric fiber orientation angle in the AFC material on the control authority of the ACLD patches is also investigated.

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]

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Output-Only Modal Analysis of an Internal Unreachable Module Embedded in a Space Electronic Equipment

2012 ◽  
Author(s):  
Lassaad Ben Fekih ◽  
Georges Kouroussis ◽  
David Wattiaux ◽  
Olivier Verlinden ◽  
Christophe De Fruytier
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Transverse Direction ◽  
Mode Shapes ◽  
Fe Model ◽  
Fe Method ◽  
Numeric Model ◽  
Stiffness Matrices ◽  
Output Only

An approach is proposed to identify the modal properties of a subsystem made up of an arbitrary chosen inner module of embedded space equipment. An experimental modal analysis was carried out along the equipment transverse direction with references taken onto its outer housing. In parallel, a numerical model using the finite element (FE) method was developed to correlate with the measured results. A static Guyan reduction has led to a set of master degrees of freedom in which the experimental mode shapes were expanded. An updating technique consisting in minimizing the dynamic residual induced by the FE model and the measurements has been investigated. A last verification has consisted in solving the numeric model composed of the new mass and stiffness matrices obtained by means of a minimization of the error in the constitutive equation method.

The Two-Scale Finite Element Estimates for Thermoelasticity in Perforated Structure with Boundary Layer

2012 ◽  
Vol 217-219 ◽  
pp. 2501-2504
Author(s):  
Ming Xiang Deng ◽  
Yong Ping Feng
Keyword(s):  
Boundary Layer ◽  
Finite Element Method ◽  
Finite Element ◽  
Higher Order ◽  
Numerical Results ◽  
Local Temperature ◽  
Coupling Problem ◽  
Local Strains ◽  
Local Stresses ◽  
Basic Configuration

The higher order two-scale finite element errors of the thermoelastic problem in perforated composites with boundary layer are presented, and the two-scale finite element method coupled with boundary layer is built for analyzing the coupling problem. The numerical results show that the basic configuration and the local temperature strongly affect local strains and local stresses.

scholarly journals k-space imaging of the eigenmodes of sharp gold tapers for scanning near-field optical microscopy

2013 ◽  
Vol 4 ◽  
pp. 603-610 ◽  
Author(s):  
Martin Esmann ◽  
Simon F Becker ◽  
Bernard B da Cunha ◽  
Jens H Brauer ◽  
Ralf Vogelgesang ◽  
...  
Keyword(s):  
Spatial Frequency ◽  
Optical Microscopy ◽  
Frequency Domain ◽  
Near Field ◽  
Higher Order ◽  
Far Field ◽  
Radiation Patterns ◽  
Background Ratio ◽  
Higher Order Modes ◽  
Spatial Frequency Domain

We investigate the radiation patterns of sharp conical gold tapers, which were designed as adiabatic nanofocusing probes for scanning near-field optical microscopy (SNOM). Field calculations show that only the lowest order eigenmode of such a taper can reach the very apex and thus induce the generation of strongly enhanced near-field signals. Higher-order modes are coupled into the far field at finite distances from the apex. Here, we demonstrate experimentally how to distinguish and separate between the lowest and higher-order eigenmodes of such a metallic taper by filtering in the spatial frequency domain. Our approach has the potential to considerably improve the signal-to-background ratio in spectroscopic experiments at the nanoscale.

MODAL ANALYSIS AND DAMPING MEASUREMENT OF THE HEAD ARM ASSEMBLY OF A SMALL FORM FACTOR HARD DISK DRIVE

2010 ◽  
Vol 24 (01n02) ◽  
pp. 26-33
Author(s):  
B. J. SHI ◽  
B. GU ◽  
D. W. SHU ◽  
T. H. JIN
Keyword(s):  
Form Factor ◽  
Modal Analysis ◽  
Hard Disk Drives ◽  
Hard Disk ◽  
Disk Drive ◽  
Numerical Results ◽  
Fe Model ◽  
Small Form ◽  
Small Form Factor ◽  
Consumer Devices

As non-traditional applications of hard disk drives (HDDs) emerge, the interest in the effects of shock and vibration on small form factor (SFF) drives has come into currency due to the increasingly hostile environments encountered in the usage of the portable computer as well as the application in consumer devices. In this paper, the dynamic characteristics of an SFF drive were investigated using both experimental and numerical techniques, including modal analysis and damping measurement of the head arm assembly (HAA) of the drive. A finite element (FE) model of the HAA was created to perform numerical analysis. The FE model was verified and modified according to numerical results and experimental results. It is found that numerical results of the HAA in it free state and those in its preloading state coincide well with those of experiments, and/or those by other researchers.

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