Loop Flexure Vibration Isolator with Constrained Viscoelastic Damping

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Solution Overview

Problem

Existing vibration isolation technologies face challenges in providing independent and wide-ranging compliance in all directions without sacrificing strength, linearity, or compactness, especially in aerospace and terrestrial applications where precise damping is critical.

Innovation Solution

A vibration isolator design incorporating a loop flexure with a constrained viscoelastic material (VEM) and posts that oppose relative motion, utilizing shear wall type constrained layer damping to reduce vibration load transmission, allowing for independently determinable compliance in all directions while maintaining strength and linearity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If passive damping is used to reduce vibration amplitudes at resonances, then vibration suppression is improved, but the structure becomes stiffer and heavier

Engineering Contradiction:
Improvevibration suppressionVSAvoidstructural stiffness
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The patent changes the physical parameters of the damping system by using magnetorheological fluid whose viscosity can be dynamically adjusted via magnetic field strength. This allows the damping coefficient to be varied without changing the structural stiffness, resolving the contradiction between vibration suppression and structural rigidity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite system combining magnetorheological fluid with magnetic field generation components. This composite approach enables active control of damping properties while maintaining structural integrity, avoiding the need to increase overall structural stiffness for damping purposes

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If vibration isolation is used to reduce transmission of vibration energy, then payload protection is improved, but the isolation system becomes more complex and heavier

Engineering Contradiction:
Improvevibration transmissionVSAvoidisolator weight
Core Design Contradiction:
Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The magnetorheological fluid's variable viscosity allows a single isolator design to adapt to different vibration conditions, eliminating the need for multiple heavy passive dampers tuned to specific frequencies. The fluid's properties change to match operational requirements, reducing overall system weight

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The active damping system provides universal vibration isolation across multiple frequency ranges and loading conditions through magnetic field control, replacing what would otherwise require multiple specialized passive dampers, thereby reducing total system weight and complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If multiple-axis compliance is provided independently, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvemulti-axis complianceVSAvoidisolator structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical compliance mechanisms with a fluid-based damping system controlled by magnetic fields. The magnetorheological fluid provides multi-axis damping compliance through viscous resistance rather than mechanical linkages, significantly reducing structural complexity while maintaining adaptability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

By controlling magnetic field parameters, the system independently adjusts damping characteristics in multiple axes without requiring separate mechanical adjustment mechanisms for each axis, simplifying the overall device structure while preserving full multi-axis compliance capability

Inventive Principle:
Principle #35Parameter changes

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 provides significant passive damping and reduced vibration load transmission, achieving high-frequency surge modes with minimal additional stiffness and weight, suitable for compact, lightweight vibration load isolation in various applications.

Implementation Method 1

a constrained layer of viscoelastic material (VEM) and a plurality of posts arranged to couple the constrained layer of VEM to the flexure

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

The combination of a post and pad may be referred to herein as a 'bridge'. The loop flexure may be of any type, including elliptical, circular or rectangular, for example. The combination of a post and pad may be referred to herein as a 'bridge'.

Methodology Applied
Scientific EffectShear wall type constrained layer damping: Damping

Implementation Method 3

The posts are attached to the loop flexure on the inside surface of the loop flexure. For purposes of the following discussion the post-ends closest to the flexure to which they are attached will be referred to as proximal ends and the post-ends farthest from the flexure to which they are attached will be referred to as distal ends.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2773561B1Vibration isolation system and method
Publication Date: 2016.09.07 MOOG INC
  • EP2773561B1 patent drawingFigure 1~2
  • EP2773561B1 patent drawingFigure 3~4
  • EP2773561B1 patent drawingFigure 5~6

AI summary

A vibration isolator (100) includes a flexure (102), a constrained VEM layer coupler (104), and a constrained VEM layer (106) configured to oppose relative translational and rotational motion between points of the flexure. The flexure may be a loop flexure and may include multiple loops that may be elliptical, circular, rectangular or square in overall aspect, for example. In multi-loop embodiments, the loops may share a common major axis or their major axes may be at an angle to one another. The device enhances damping by providing an increase in viscoelastic surface area over that available in the surface area of the flexure and provides a method of adjusting the strain in the VEM as the flexure undergoes deflection.