Variable Stiffness Liquid Inertia Vibration Isolator
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Solution Overview
Problem
Conventional vibration isolation systems, such as liquid inertia vibration eliminators, are complex and costly, limiting their ability to effectively attenuate a range of vibration frequencies without requiring replacement or modification of internal components.
Innovation Solution
A variable stiffness liquid inertia vibration isolation device that incorporates a variable stiffness spring, allowing the stiffness of the LIVE isolator to be selectively adjusted using a stepper motor-driven elastomeric pad, enabling a range of isolation frequencies without altering the internal components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional LIVE isolators are designed to attenuate at a single vibration frequency, then the isolation effectiveness at that specific frequency is improved, but the adaptability to attenuate various vibration frequencies deteriorates
Solution Approach 1:
The patent applies the dynamics principle by making the tuning mass variable rather than fixed. The tuning mass can be dynamically adjusted to different positions along the piston, allowing the isolator to adapt to various vibration frequencies. This resolves the contradiction by enabling the system to maintain high isolation effectiveness at different frequencies through dynamic reconfiguration of the mass distribution.
Solution Approach 2:
The patent changes the parameter of the tuning mass from a fixed value to a variable value that can be repositioned. By altering the position parameter of the tuning mass along the piston, the system can tune to different vibration frequencies, thus achieving both high isolation effectiveness and frequency adaptability.
2Adaptability or versatility
If variable LIVE isolators alter the tuning mass or embed active actuators to achieve variable frequency attenuation, then the adaptability to various vibration frequencies is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the complex active actuators (such as piezoelectric actuators) from the isolator structure and replaces them with a simpler manual or mechanical adjustment mechanism for repositioning the tuning mass. This extraction of unnecessary complex components reduces device complexity and cost while maintaining the ability to achieve variable frequency attenuation.
Solution Approach 2:
The patent employs a simpler, more cost-effective adjustment mechanism for repositioning the tuning mass, replacing expensive active actuators with a more economical solution that achieves the same functional goal of variable frequency tuning.
3Adaptability or versatility
If existing non-variable LIVE isolators are replaced with variable LIVE isolators, then the frequency adaptability is improved, but the loss of time and additional cost for replacement occur
Solution Approach 1:
The patent transforms the static, non-variable isolator into a dynamic, variable-frequency isolator by incorporating a repositionable tuning mass mechanism. This allows existing isolators to be upgraded in-place, avoiding complete replacement and reducing both time and cost while achieving frequency adaptability.
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 system provides a less complex and cost-effective means to achieve variable frequency isolation, allowing existing non-variable isolators to be modified for multiple frequency attenuation without internal component changes, thus enhancing vibration control in structures like aircraft.
Implementation Method 1
LIVE isolators employ a dense, low-viscosity fluid as a 'tuning' mass to counterbalance, or cancel, oscillating forces transmitted through the isolator
Implementation Method 2
A variable stiffness liquid inertia vibration isolation device that incorporates a variable stiffness spring, allowing the stiffness of the LIVE isolator to be selectively adjusted using a stepper motor-driven elastomeric pad
Implementation Method 3
In one embodiment, the elastomeric pad is rotated, for example, by a stepper motor, to change the stiffness that is seen by the LIVE isolator and, correspondingly, vary the stiffness of the LIVE isolator
Data Source
Figure 1
Figure 2~3
AI summary
A variable stiffness liquid inertia vibration isolation device includes a liquid inertia vibration elimination isolator and a variable stiffness spring operably associated with the liquid inertia vibration elimination isolator for varying the stiffness of the liquid inertia vibration isolator. The variable stiffness spring may include an elastomeric pad exhibiting a first stiffness along a first axis and a second stiffness, significantly greater than the first stiffness, along a second axis that is perpendicular to the first axis.