scholarly journals Optimization on microlattice materials for sound absorption by an integrated transfer matrix method

2015 ◽  
Vol 137 (4) ◽  
pp. EL334-EL339 ◽  
Author(s):  
Xiaobing Cai ◽  
Jun Yang ◽  
Gengkai Hu
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Sound Absorption

Computation of the Alpha Cabin Sound Absorption Coefficient by Using the Finite Transfer Matrix Method (FTMM): Inter-Laboratory Test on Porous Media

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Andrea Santoni ◽  
Paolo Bonfiglio ◽  
Patrizio Fausti ◽  
Francesco Pompoli
Keyword(s):  
Absorption Coefficient ◽  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Sound Absorption ◽  
Finite Size ◽  
Sound Absorption Coefficient ◽  
Radiation Impedance ◽  
Simulation Based ◽  
Private Research

Abstract The transfer matrix method (TMM) has become an established and widely used approach to compute the sound absorption coefficient of a multilayer structure. Due to the assumption made by this method of laterally infinite media, it is necessary to introduce in the computation the finite-size radiation impedance of the investigated system, in order to obtain an accurate prediction of the sound absorption coefficient within the entire frequency range of interest; this is generally referred to as finite transfer matrix method (FTMM). However, it has not been extensively investigated the possibility of using the FTMM to accurately approximate the sound absorption of flat porous samples experimentally determined in an Alpha Cabin, a small reverberation room employed in the automotive industry. To this purpose, a simulation-based round robin test was organized involving academic and private research groups. Four different systems constituted by five porous materials, whose properties were experimentally characterized, were considered. Each participant, provided with all the mechanical and physical properties of each medium, was requested to simulate the sound absorption coefficient with an arbitrary chosen code, based on the FTMM. The results indicated a good accuracy of the different formulations to determine the finite-size radiation impedance. However, its implementation in the computation of the sound absorption coefficient as well as the upper limit of the range of incidence angles within which the acoustic field is simulated, and the model adopted to describe each material, significantly influenced the results.

The transfer matrix method for lattice proteins—an application with cooperative interactions

Polymer ◽  
2004 ◽  
Vol 45 (2) ◽  
pp. 707-716 ◽  
Author(s):  
Andrzej Kloczkowski ◽  
Taner Z. Sen ◽  
Robert L. Jernigan
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Cooperative Interactions ◽  
Lattice Proteins

A Modified Transfer Matrix Method for Asymmetric Rotor-Bearing Systems

1994 ◽  
Vol 116 (3) ◽  
pp. 309-317 ◽  
Author(s):  
Yuan Kang ◽  
An-Chen Lee ◽  
Yuan-Pin Shih
Keyword(s):  
Transfer Matrix ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Harmonic Balance Method ◽  
Continuous System ◽  
Euler Beam ◽  
Rotating Shaft ◽  
Rotor Bearing ◽  
Asymmetric Rotor ◽  
Steady State Responses

A modified transfer matrix method (MTMM) is developed to analyze rotor-bearing systems with an asymmetric shaft and asymmetric disks. The rotating shaft is modeled by a Rayleigh-Euler beam considering the effects of the rotary inertia and gyroscopic moments. Specifically, a transfer matrix of the asymmetric shaft segments is derived in a continuous-system sense to give accurate solutions. The harmonic balance method is incorporated in the transfer matrix equations, so that steady-state responses of synchronous and superharmonic whirls can be determined. A numerical example is presented to demonstrate the effectiveness of this approach.

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