TY - GEN
T1 - Design, Fabrication, and Testing of Stiffened Composite Panels with Acoustically Tailored Stiffeners
AU - Brown, Avery
AU - Moorhouse, Anna M.
AU - Bakis, Charles E.
AU - Smith, Edward
AU - Beck, Benjamin S.
AU - Shepherd, Micah R.
N1 - Funding Information:
This research was funded by the Office of Naval Research Agreement No. N00014-21-1-2147. The U.S. Government is
Publisher Copyright:
Copyright © 2023 by the Vertical Flight Society. All rights reserved.
PY - 2023
Y1 - 2023
N2 - Carbon fiber reinforced epoxy composites are being increasingly used for load bearing structural elements in large transport rotorcraft. However, due to the increased stiffness-to-density ratio of composites, problems associated with vibration and interior noise can be exacerbated by the use of composites in airframes. The current investigation explores the potential of optimized composite meta-structures to reduce vibration and interior noise in rotorcraft. The approach involves designing a taper into the thickness of blade stiffeners which, when combined with a limited amount of absorbing material in the thinned region, creates what is known as an “acoustic black hole” (ABH) in the stiffener. It is hypothesized that optimally designed ABH stiffeners can reduce broadband vibrations in stiffened panels. An optimization routine has been developed to determine the tradeoffs between vibration, mass, and buckling load due to compression parallel to the stiffeners. The tradeoffs are visualized using a 3-D Pareto front that helps the designer decide on the optimal design. Carbon/epoxy panels were made using vacuum-bag-oven processing with out-of-autoclave prepreg and verified to be of good quality. Panel vibration, buckling onset, and post-buckling load-deflection behavior were simulated using finite elements and measured using model testing and compression testing. Based on preliminary results, ABH-tapered stiffened panels have the ability to reduce radiated noise without a significant penalty in the mass and compressive load-bearing capability.
AB - Carbon fiber reinforced epoxy composites are being increasingly used for load bearing structural elements in large transport rotorcraft. However, due to the increased stiffness-to-density ratio of composites, problems associated with vibration and interior noise can be exacerbated by the use of composites in airframes. The current investigation explores the potential of optimized composite meta-structures to reduce vibration and interior noise in rotorcraft. The approach involves designing a taper into the thickness of blade stiffeners which, when combined with a limited amount of absorbing material in the thinned region, creates what is known as an “acoustic black hole” (ABH) in the stiffener. It is hypothesized that optimally designed ABH stiffeners can reduce broadband vibrations in stiffened panels. An optimization routine has been developed to determine the tradeoffs between vibration, mass, and buckling load due to compression parallel to the stiffeners. The tradeoffs are visualized using a 3-D Pareto front that helps the designer decide on the optimal design. Carbon/epoxy panels were made using vacuum-bag-oven processing with out-of-autoclave prepreg and verified to be of good quality. Panel vibration, buckling onset, and post-buckling load-deflection behavior were simulated using finite elements and measured using model testing and compression testing. Based on preliminary results, ABH-tapered stiffened panels have the ability to reduce radiated noise without a significant penalty in the mass and compressive load-bearing capability.
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M3 - Conference contribution
AN - SCOPUS:85167705244
T3 - FORUM 2023 - Vertical Flight Society 79th Annual Forum and Technology Display
BT - FORUM 2023 - Vertical Flight Society 79th Annual Forum and Technology Display
PB - Vertical Flight Society
T2 - 79th Vertical Flight Society Annual Forum and Technology Display, FORUM 2023
Y2 - 16 May 2023 through 18 May 2023
ER -