SIMCV un simulateur analogue de la propagation du son dans le conduit vocal

2007 ◽  
Vol 85 (12) ◽  
pp. 1325-1341 ◽  
Author(s):  
H Teffahi
Keyword(s):  
Wave Propagation ◽  
Transfer Function ◽  
Vocal Tract ◽  
Simulation Method ◽  
Formant Frequencies ◽  
Differential Contribution

Wave propagation in a vocal tract incurring losses with yielding walls is studied. The simulation method of this vocal tract is described. The adopted method allowed us to calculate the transfer function, the formant frequencies, and the formant bandwidths of the vocal tract. The results obtained permit the determination of the differential contribution of the different loss sources for formant frequencies and formant bandwidths.

scholarly journals Formant frequencies and bandwidths of the vocal tract transfer function are affected by the mechanical impedance of the vocal tract wall

2014 ◽  
Vol 14 (4) ◽  
pp. 719-733 ◽  
Author(s):  
Mario Fleischer ◽  
Silke Pinkert ◽  
Willy Mattheus ◽  
Alexander Mainka ◽  
Dirk Mürbe
Keyword(s):  
Transfer Function ◽  
Vocal Tract ◽  
Mechanical Impedance ◽  
Formant Frequencies

scholarly journals Determination of Fractured Rock’s Representative Elementary Volume by a Numerical Simulation Method

2019 ◽  
Vol 9 (4) ◽  
pp. 4448-4451
Author(s):  
H. Gasmi ◽  
M. Touahmia ◽  
A. Torchani ◽  
E. Hamdi ◽  
A. Boudjemline
Keyword(s):  
Wave Propagation ◽  
Simulation Method ◽  
Fracture Network ◽  
Homogenization Method ◽  
Representative Elementary Volume ◽  
Elementary Volume ◽  
Fractured Network ◽  
Numerical Program

The present study aims at developing a numerical program called DISSIM which can analyze the homogenization of rock massifs using a new subroutine which calculates Representative Elementary Volume (REV). The DISSIM methodology consists of two steps. The first step involves the modeling of the fractured network in order to provide a surface simulation that represents the real fracture of the examined front. The second step is to numerically model the wave propagation through the simulated fracture network while characterizing the attenuation of vibrations due to the effect of discontinuities. This part allows us to determine in particular the wave propagation velocity through the fractured mass, from which we can determine the homogenized Young's modulus. However, after extensive bibliographic research, it was realized that a third step appeared to be necessary. In fact, it is necessary to look for a representative elementary volume on which we apply the proposed homogenization method. Two types of the representative elementary volume are proposed in this article, the geometric REV and the mechanical REV. The presentation of these two types of REV and the DISSIM methodology are detailed in this paper. Then, this methodology was applied to the study of a real case. The present research provides a method allowing the calculation of both types of REV for fissured rocks. The case study yielded comparable results between the mechanical REV and the geometric REV, which is compatible with previous research studies.

scholarly journals Determination of positive realizations with reduced numbers of delays or without delays for discrete-time linear systems

2012 ◽  
Vol 22 (4) ◽  
pp. 451-465 ◽  
Author(s):  
Tadeusz Kaczorek
Keyword(s):  
Transfer Function ◽  
Linear Systems ◽  
Discrete Time ◽  
Sufficient Conditions ◽  
Diagram Method ◽  
State Variable ◽  
Discrete Time Systems ◽  
Time Systems ◽  
Time Linear

A new modified state variable diagram method is proposed for determination of positive realizations with reduced numbers of delays and without delays of linear discrete-time systems for a given transfer function. Sufficient conditions for the existence of the positive realizations of given proper transfer function are established. It is shown that there exists a positive realization with reduced numbers of delays if there exists a positive realization without delays but with greater dimension. The proposed methods are demonstrated on a numerical example.

Error analyses of a Multi-Input-Multi-Output cantilever beam test

2021 ◽  
pp. 107754632110337
Author(s):  
Arup Maji ◽  
Fernando Moreu ◽  
James Woodall ◽  
Maimuna Hossain
Keyword(s):  
Transfer Function ◽  
Frequency Domain ◽  
Cantilever Beam ◽  
Transfer Functions ◽  
Linear Superposition ◽  
Transfer Function Matrix ◽  
Error Analyses ◽  
Pseudo Inverse ◽  
Function Matrix

Multi-Input-Multi-Output vibration testing typically requires the determination of inputs to achieve desired response at multiple locations. First, the responses due to each input are quantified in terms of complex transfer functions in the frequency domain. In this study, two Inputs and five Responses were used leading to a 5 × 2 transfer function matrix. Inputs corresponding to the desired Responses are then computed by inversion of the rectangular matrix using Pseudo-Inverse techniques that involve least-squared solutions. It is important to understand and quantify the various sources of errors in this process toward improved implementation of Multi-Input-Multi-Output testing. In this article, tests on a cantilever beam with two actuators (input controlled smart shakers) were used as Inputs while acceleration Responses were measured at five locations including the two input locations. Variation among tests was quantified including its impact on transfer functions across the relevant frequency domain. Accuracy of linear superposition of the influence of two actuators was quantified to investigate the influence of relative phase information. Finally, the accuracy of the Multi-Input-Multi-Output inversion process was investigated while varying the number of Responses from 2 (square transfer function matrix) to 5 (full-rectangular transfer function matrix). Results were examined in the context of the resonances and anti-resonances of the system as well as the ability of the actuators to provide actuation energy across the domain. Improved understanding of the sources of uncertainty from this study can be used for more complex Multi-Input-Multi-Output experiments.

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