Variable Stiffness Support for Aircraft Vibration Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vibration control methods for dynamic systems, such as aircraft structures, are inadequate in effectively changing stiffness to prevent adverse resonant conditions, often requiring heavy and impractical solutions or providing limited frequency band isolation.
Innovation Solution
A compact, lightweight variable stiffness support device with a worm gear assembly that adjusts the orientation of an elastomer assembly, allowing continuous stiffness adjustment at structural joints to tune natural frequencies and respond to applied forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional vibration isolation methods are used to control resonant conditions in dynamic systems, then vibration control is achieved, but significant weight is added to the airframe structure
Solution Approach 1:
The patent applies the dynamics principle by making the support structure's stiffness variable rather than fixed. The actively controlled support changes its stiffness properties in real-time to adapt to varying operating conditions, allowing the system to control vibrations effectively without requiring the always-on, heavy stiffening that traditional methods would demand.
Solution Approach 2:
The patent implements parameter changes by actively modifying the stiffness parameter of the support structure. The controlled support adjusts its mechanical properties (stiffness) based on operating conditions, enabling the system to maintain vibration control across different regimes without the permanent weight penalty of a always-stiff design.
2Reliability
If the stiffness of the support is increased to raise natural frequencies above driving frequencies, then resonance is avoided, but the structure becomes excessively stiff and heavy
Solution Approach 1:
The patent applies dynamics by transitioning from a static, always-stiff support to an actively controlled, variable-stiffness support. The support dynamically adjusts its stiffness to raise natural frequencies only when needed to avoid resonance, rather than maintaining high stiffness continuously, thus avoiding excessive structural strength and weight.
Solution Approach 2:
The patent uses parameter changes by actively modifying the stiffness parameter of the support based on operating conditions. The controlled support increases stiffness only when resonance avoidance is required, and reduces it when not needed, preventing the structure from being permanently over-stiffened and weighted down.
3Reliability
If flexible elements are used to isolate vibrating components, then vibration isolation is achieved, but the support becomes too soft causing excessive deflections under load
Solution Approach 1:
The patent applies dynamics by making the support stiffness adjustable rather than fixed at a soft value. The actively controlled support can soften to provide vibration isolation when needed, while simultaneously having the capability to stiffen when load-bearing capacity is required, thus avoiding excessive deflections without sacrificing isolation performance.
Solution Approach 2:
The patent implements parameter changes by actively modifying the stiffness parameter of the support. The controlled support adjusts its stiffness to be soft enough for vibration isolation when operating conditions permit, but stiff enough to prevent excessive deflections when loads increase, optimizing both isolation and structural integrity.
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
Enables real-time tuning of natural frequencies, reducing vibrations and wear, and providing a wide range of stiffness adjustments without mechanical stops, thus effectively preventing resonant conditions and enhancing payload capacity and range.
Implementation Method 1
an elastomeric material embedded within an outer ring-shaped housing and having a central bushing embedded therein
Implementation Method 2
adjustment mechanism is a worm gear assembly having a worm driven by a gear motor, and an external gear coupled to the elastomer assembly
Data Source
AI summary
A variable stiffness support has a support housing that is configured to adjust the orientation of an internal elastomer assembly. The support housing includes an adjustment mechanism, and the elastomer assembly includes an outer ring that encircles an elastomeric material, a central bushing embedded in the elastomeric material, and a plurality of shims embedded in the elastomeric material in a parallel planar fashion.