Acoustic Resonator for Aircraft Wheel Bin Vibration Damping
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Solution Overview
Problem
Aircraft experience undesirable vibrations due to aerodynamic effects, specifically air-flow over open wheel bins causing pressure fluctuations that excite the wheel bins and transfer vibrations to the wing-to-body fairing and fuselage, which are not effectively mitigated by existing solutions.
Innovation Solution
An acoustic resonator is mounted to the outer surface of the wheel bin, tuned to have a resonant frequency similar to the cavity modal frequency of the wheel bin at aircraft flight conditions, to dampen the pressure fluctuations and vibrations by being in fluid communication with the cavity and adjusting its neck diameter and length for optimal placement and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an acoustic resonator is added to the wheel bin, then vibration damping is improved, but device complexity increases
Solution Approach 1:
The patent applies resonance theory by tuning the acoustic resonator's natural frequency to match the cavity modal frequency of the wheel bin. This creates a controlled vibrational response in the resonator that generates counteracting pressure fluctuations to dampen the harmful vibrations in the wheel bin cavity, directly addressing the vibration problem through vibrational mechanics.
Solution Approach 2:
The acoustic resonator serves as an intermediary device between the airflow source and the wheel bin cavity. It mediates the interaction by transforming the aerodynamic excitation into controlled acoustic oscillations that cancel the harmful vibrations, providing a buffer that reduces the direct coupling between the airflow and the cavity modes.
2Object-affected harmful factors
If the acoustic resonator is tuned to cavity modal frequency, then vibration damping is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter adjustment by varying the physical dimensions of the acoustic resonator (such as cavity volume, neck diameter, and neck length) to change its natural frequency. This allows the resonator to be tuned to match the specific cavity modal frequency of the wheel bin, optimizing the vibration damping performance through parameter optimization.
3Object-affected harmful factors
If the resonator neck dimensions are adjusted for optimal performance, then vibration damping is improved, but device complexity increases
Solution Approach 1:
The patent systematically adjusts the geometric parameters of the resonator neck (diameter, length, and shape) to optimize the coupling between the resonator and the wheel bin cavity. These parameter changes are designed to maximize the damping effect while maintaining a relatively simple overall structure, balancing performance improvement with structural simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The acoustic resonator significantly reduces the amplitude of excitation at the cavity modal frequency, thereby minimizing the transfer of vibrations to the fuselage, providing effective damping of the acoustic mode and eliminating undesirable vibrations.
Implementation Method 1
an acoustic resonator mounted to an outer surface of the side wall of the at least one wheel bin and in fluid communication with the cavity, the acoustic resonator having a resonant frequency substantially similar to a cavity modal frequency of the at least one wheel bin at an aircraft flight condition
Implementation Method 2
the acoustic resonator is a Helmholtz resonator
Data Source
AI summary
An aircraft fairing includes a fairing body having an exterior fairing wall and at least one wheel bin. The at least one wheel bin has a side wall extending from an opening in the exterior fairing wall to an end wall. The side wall and the end wall define a cavity of the at least one wheel bin in fluid communication with the opening in the exterior fairing wall. An acoustic resonator is mounted to an outer surface of the side wall of the at least one wheel bin and is in fluid communication with the cavity. The acoustic resonator has a resonant frequency substantially similar to a cavity modal frequency of the at least one wheel bin at an aircraft flight condition.