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Mechanical Engineering

Selected Works

Olivier Doutres Ph.D.

2011

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Optimization Of The Acoustic Performance Of Polyimide Foams, Olivier Doutres, Noureddine Atalla, Rebecca Wulliman, Shari Ferguson, Steve Bailey Jul 2011

Optimization Of The Acoustic Performance Of Polyimide Foams, Olivier Doutres, Noureddine Atalla, Rebecca Wulliman, Shari Ferguson, Steve Bailey

Olivier Doutres Ph.D.

Due to their low weight, high fire resistance and good mechanical strength, SOLIMIDE® Polyimide foams are good candidates for sound packages in aerospace sound transmission applications. However, their high resistance to airflow limits the sound absorption efficiency inside a double wall structure and thus the sound transmission loss of the structure. The paper discusses two concepts to improve the transmission efficiency of such materials for double wall applications: (i) improving its sound absorption behavior by removing mechanically or chemically the cell membranes and thus decreasing both the flow resistance and tortuosity, (ii) coupling the Polyimide foams to screens (porous or …


A Practical Impedance Tube Method To Estimate The Normal Incidence Sound Transmission Loss Of Double Wall Structure, Olivier Doutres, Noureddine Atalla Jul 2011

A Practical Impedance Tube Method To Estimate The Normal Incidence Sound Transmission Loss Of Double Wall Structure, Olivier Doutres, Noureddine Atalla

Olivier Doutres Ph.D.

The objective of this paper is to propose a practical impedance tube method to optimize the sound transmission loss of double wall structure by concentrating on the sound package placed inside the structure. In a previous work, the authors derived an expression that breaks down the transmission loss of a double wall structure containing a sound absorbing blanket separated from the panels by air layers in terms of three main contributions; (i) sound transmission loss of the panels, (ii) sound transmission loss of the blanket and (iii) sound absorption due to multiple reflections inside the cavity. The sound transmission loss …