Title

Effects of Mechanical Tolerances on Realized Attenuation

Presenter Information

Timothy Richard Peters

Department

Mechanical and Aerospace Engineering

Major

Aerospace Engineering

Research Advisor

Eversman, Walter

Advisor's Department

Mechanical and Aerospace Engineering

Funding Source

Spirit Aerosystems

Abstract

A Monte Carlo analysis, coupled with non-intrusive polynomial chaos methods, is used to examine the effect of mechanical tolerances on realized attenuation of two degree of freedom linings for duct acoustic propagation. A probability density function for impedance is developed by representing lining physical and geometric tolerances with randomized distributions. Eight total parameters, such as lining thickness and hole diameter, are allowed to vary. Non-intrusive polynomial chaos methods are used with a finite element duct propagation code to examine the effect on predicted attenuation. This analysis scheme is performed for sideline and approach cases of two sub-optimum acoustic linings for turbofan engines. It is found that variations in lining parameters cause a significant deviation from the nominal impedance and consequently affect attenuation. The results of this study can be used to determine which lining parameters should be closely monitored during the manufacturing process to achieve the desired attenuation.

Biography

Timothy Peters is a senior in Aerospace Engineering at Missouri University of Science and Technology. He has a special interest in aircraft engine structures. Timothy is also the chief engineer of the aircraft portion of Advanced Aero Vehicle Group at Missouri S&T. After graduating, Timothy will be working as a structural analyst for Spirit Aerosystems in Wichita, Kansas.

Research Category

Engineering

Presentation Type

Poster Presentation

Document Type

Poster

Award

Engineering poster session, First place

Location

Upper Atrium/Hallway

Presentation Date

07 Apr 2010, 1:00 pm - 3:00 pm

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Apr 7th, 1:00 PM Apr 7th, 3:00 PM

Effects of Mechanical Tolerances on Realized Attenuation

Upper Atrium/Hallway

A Monte Carlo analysis, coupled with non-intrusive polynomial chaos methods, is used to examine the effect of mechanical tolerances on realized attenuation of two degree of freedom linings for duct acoustic propagation. A probability density function for impedance is developed by representing lining physical and geometric tolerances with randomized distributions. Eight total parameters, such as lining thickness and hole diameter, are allowed to vary. Non-intrusive polynomial chaos methods are used with a finite element duct propagation code to examine the effect on predicted attenuation. This analysis scheme is performed for sideline and approach cases of two sub-optimum acoustic linings for turbofan engines. It is found that variations in lining parameters cause a significant deviation from the nominal impedance and consequently affect attenuation. The results of this study can be used to determine which lining parameters should be closely monitored during the manufacturing process to achieve the desired attenuation.