Rotary-Wing Aircraft Damper Stiffness Control for External Load Resonance
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Solution Overview
Problem
Rotary-wing aircraft face resonance issues with external devices due to variations in mass during flight, leading to increased vibration amplitudes and potential instability.
Innovation Solution
A rotary-wing aircraft design incorporating a mass variation device mounted on a fuselage with a stiffness variable damper system, which adjusts its stiffness in response to mass changes using a controller to maintain natural frequencies outside resonance ranges with fuselage vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If external devices are mounted on the fuselage, then additional functions are added to the aircraft, but resonance occurs due to mass variation during flight
Solution Approach 1:
The damper stiffness is made dynamically adjustable through a stiffness variable mechanism that changes the damping characteristics in response to mass variations of external devices during flight, preventing resonance across different operational phases
Solution Approach 2:
The physical parameter of damper stiffness is changed during flight operations to match the varying mass conditions of mounted external devices, thereby maintaining optimal vibration suppression and avoiding resonant frequencies
2Object-affected harmful factors
If damper stiffness is increased to reduce vibration, then vibration amplitudes are reduced, but natural frequency may align with fuselage vibration frequencies causing resonance
Solution Approach 1:
The damper system transitions from static to dynamic stiffness control, where the stiffness variable mechanism continuously or periodically adjusts damping properties to maintain natural frequency separation from fuselage vibration frequencies while suppressing harmful vibrations
Solution Approach 2:
The system incorporates feedback control where vibration sensors detect fuselage vibrations and mass variations, and the stiffness variable mechanism adjusts damper characteristics in response to maintain optimal vibration suppression without resonant alignment
3Adaptability or versatility
If mass variation devices are used during flight, then operational flexibility is improved, but natural frequency changes causing resonance with fuselage vibrations
Solution Approach 1:
The damper stiffness is dynamically adjusted to compensate for mass variations in external devices, maintaining stable natural frequency characteristics despite changing operational configurations during flight
Solution Approach 2:
The damper's physical parameter (stiffness) is changed in response to mass parameter changes in external devices, thereby maintaining constant natural frequency and avoiding resonance across different operational states
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 solution effectively reduces resonance and vibration amplitudes of external devices, ensuring stable flight even as the mass of these devices varies, by dynamically controlling the damper's stiffness to prevent natural frequency alignment with fuselage vibrations.
Implementation Method 1
The damper couples the fuselage to the mounting device and supports the mounting device. The damper includes a stiffness variable mechanism configured to adjust stiffness of the damper during flight
Implementation Method 2
The damper includes a stiffness variable mechanism configured to adjust stiffness of the damper during flight in response to variation in the mass of the mass variation device during flight
Data Source
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AI summary
A rotary-wing aircraft includes a fuselage (2), and an external device (10). The fuselage (2) is provided with a rotary wing (4). The external device (10) is mounted on the outside of the fuselage (2). The external device (10) includes a mounting device (12), a mass variation device (14), and a damper (16). The mounting device (12) is fixed to the fuselage (2) and disposed so as to project in a lateral direction of the fuselage (2). The mass variation device (14) is mounted on the mounting device (12) and has a mass that varies as the mass variation device (14) is used. The damper (16) couples the fuselage (2) to the mounting device (12) and supports the mounting device (12). The damper (16) includes a stiffness variable mechanism (20) configured to change stiffness of the damper (16) in response to variation in the mass of the mass variation device (14).