Rotary-Wing External Mount Damping for Variable-Mass Resonance
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Solution Overview
Problem
Rotary-wing aircraft face resonance issues with external devices due to varying mass, leading to increased vibration amplitudes when the natural frequency of these devices aligns with fuselage vibration frequencies.
Innovation Solution
A rotary-wing aircraft design incorporating a mounting device, mass variation device, and a damper with a stiffness variable mechanism, where the damper's stiffness is controlled by a controller to maintain the natural frequency of external devices outside the resonance range with fuselage vibrations, using hydraulic or magneto-rheological dampers to absorb and attenuate vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the mass of the external device is increased to provide additional functions, then the functionality is improved, but the resonance risk with fuselage vibrations increases
Solution Approach 1:
The damper's stiffness is made dynamically adjustable through a control system that modifies the stiffness parameter in real-time. This allows the natural frequency of the external device to be actively controlled, preventing resonance with fuselage vibrations while maintaining the added functionality of the external device.
Solution Approach 2:
The control system changes the stiffness parameter of the damper based on detected vibration conditions. By adjusting this physical parameter, the natural frequency of the external device is modified to avoid resonance frequencies of the fuselage, thus eliminating the harmful resonance effect while preserving the external device's functional mass.
2Device complexity
If a fixed stiffness damper is used to support the external device, then the structure is simple, but the resonance issue cannot be addressed when mass varies
Solution Approach 1:
The damper incorporates a control mechanism that enables dynamic adjustment of stiffness, transforming a simple fixed-structure into an adaptive system. This additional complexity in the damper structure enables reliable resonance control by allowing real-time modification of the natural frequency to match varying mass conditions of the external device.
Solution Approach 2:
The control system modifies the stiffness parameter of the damper based on the varying mass of the external device. By changing this physical parameter dynamically, the system maintains reliable resonance control even as the external device's mass changes during operation, preventing resonance issues that would occur with fixed stiffness designs.
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
Effectively reduces resonance and vibration amplitudes of external devices by dynamically adjusting the damper's stiffness in response to mass variations, ensuring stable flight even when external device mass changes.
Implementation Method 1
a damper that couples the fuselage to the mounting device and supports the mounting device
Implementation Method 2
using hydraulic or magneto-rheological dampers to absorb and attenuate vibrations
Data Source
AI summary
A rotary-wing aircraft includes a fuselage, and an external device. The fuselage is provided with a rotary wing. The external device is mounted on the outside of the fuselage. The external device includes a mounting device, a mass variation device, and a damper. The mounting device is fixed to the fuselage and disposed so as to project in a lateral direction of the fuselage. The mass variation device is mounted on the mounting device and has mass that varies as the mass variation device is used. The damper couples the fuselage to the mounting device and supports the mounting device. The damper includes a stiffness variable mechanism configured to change stiffness of the damper in response to variation in the mass of the mass variation device.