Rotary Wing Fuselage Stiffened Panel Damping
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Solution Overview
Problem
Rotary wing aircrafts with structural stiffened panels face challenges in achieving both structural weight efficiency and effective noise and vibration damping, as conventional methods either compromise weight efficiency or are impractical due to additional weight and complexity from add-on damping patches or materials.
Innovation Solution
Incorporating a compound skin with a viscoelastic layer sandwiched between inner and outer skins, which are made of metal or fiber-reinforced polymers, to provide integrated damping while maintaining structural integrity and reducing weight, along with interleaf stripes for riveting support to prevent pre-tension loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional add-on damping patches or materials are applied to structural stiffened panels, then noise and vibration damping is improved, but structural weight efficiency deteriorates due to additional weight and complexity
Solution Approach 1:
The patent merges the damping function with the structural skin by integrating a viscoelastic core element sandwiched between inner and outer skins, creating a compound skin structure that simultaneously provides structural support and vibration damping without requiring separate add-on damping patches
Solution Approach 2:
The patent employs composite material construction by combining metal or fiber-reinforced polymer skins with a viscoelastic core element, creating a multi-material compound skin that achieves both structural integrity and noise/vibration damping properties
2Weight of moving object
If thin stressed skin is used in structural stiffened panels, then structural weight efficiency is improved, but noise radiation increases due to small thickness and dynamic excitation
Solution Approach 1:
The patent uses composite material construction by combining metal or fiber-reinforced polymer skins with a viscoelastic core element, creating a multi-material compound skin that achieves both structural integrity and noise/vibration damping properties
Solution Approach 2:
The patent changes the physical parameters of the skin structure by introducing a viscoelastic core element with specific damping properties, transforming the skin from a simple thin structure to a compound structure with enhanced vibration damping capability
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
This design enhances noise and vibration damping efficiency while maintaining structural weight efficiency, offering improved acoustic behavior and fire resistance, with reduced material costs and weight compared to traditional methods.
Implementation Method 1
The viscoelastic core element (14) is provided for noise and vibration damping
Implementation Method 2
The viscoelastic material exhibits an intrinsic elastic hysteresis behavior during loading and unloading cycles, which results in dissipation of mechanical energy as an effect of the material's internal friction
Implementation Method 3
the vibro-acoustic behavior of an aircraft airframe, such as a fuselage of a rotary wing aircraft that comprises structural stiffened panels, is best controlled at its source, i. e. at the structural stiffened panels, by means of structural damping approaches
Data Source
AI summary
A rotary wing aircraft with a fuselage that comprises at least one structural stiffened panel, the structural stiffened panel comprising a stressed skin and a stiffening framework that is rigidly attached to the stressed skin, wherein the stressed skin comprises an inner skin, an outer skin and a core element assembly that is arranged between the inner skin and the outer skin, the core element assembly comprising at least one viscoelastic core element and at least one intermediate core element that are tessellated, wherein the at least one viscoelastic core element is provided for noise and vibration damping.