Active Vibration Controller Using Magnetic Viscoelastic Elastomer
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Solution Overview
Problem
Conventional passive-type vibration absorbers have limited damping effectiveness when the frequency of disturbance vibration differs from their eigenfrequency or varies over time, while active mass dampers are costly and complex to control. Semi-active methods offer intermediate solutions but face inefficiencies in applying magnetic fields to magnetic viscoelastic elastomers due to uneven distribution of magnetic powder, leading to increased stiffness and manufacturing costs.
Innovation Solution
An active vibration controller design that concentrates magnetic powder and applies a magnetic field specifically to the target area of a magnetic viscoelastic elastomer, using a housing with first and second magnetic members, an exciting coil, and a magnetic viscoelastic elastomer to efficiently vary stiffness based on the magnetic field intensity, allowing for controlled damping across varying frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If magnetic powder is distributed uniformly throughout the magnetic viscoelastic elastomer, then the magnetic field can be applied to all parts, but the lower limit of base stiffness increases and manufacturing cost increases
Solution Approach 1:
The patent applies local quality by concentrating magnetic powder specifically in the central region of the magnetic viscoelastic elastomer rather than distributing it uniformly throughout. This localized concentration of magnetic particles in the core area allows the magnetic field to be applied efficiently to the region that most contributes to stiffness variation, while avoiding unnecessary magnetic powder in peripheral areas that would increase base stiffness and manufacturing cost without providing proportional benefit.
2Productivity
If magnetic powder is distributed in large amount to parts not contributing to stiffness change, then the magnetic field can be applied broadly, but the lower limit of stiffness increases and magnetic field application efficiency decreases
Solution Approach 1:
The patent implements local quality by strategically concentrating magnetic powder in the central region where it most effectively contributes to stiffness modulation. This localized distribution eliminates waste of magnetic powder in peripheral regions that do not significantly contribute to stiffness change, thereby improving magnetic field application efficiency while maintaining or reducing the lower limit of stiffness.
Solution Approach 2:
The patent applies the extraction principle by removing magnetic powder from regions that do not largely contribute to stiffness variation (the peripheral areas) and concentrating it in the central region. This extraction of unnecessary magnetic material from non-critical areas reduces both the lower limit of stiffness and manufacturing cost while maintaining effective magnetic field application where it is most needed.
3Device complexity
If passive-type vibration absorber is used with fixed physical properties, then the device is simple, but the damping effect is insufficient when disturbance frequency varies or differs from eigenfrequency
Solution Approach 1:
The patent applies the dynamics principle by making the physical properties of the vibration absorber adjustable through the magnetic field. The stiffness of the magnetic viscoelastic elastomer can be dynamically changed by applying different magnetic field intensities, allowing the system to adapt to varying disturbance frequencies. This dynamic adjustability maintains damping effectiveness across different operating conditions while keeping the device structure relatively simple compared to active control systems.
Solution Approach 2:
The patent implements parameter changes by utilizing the magnetic field to alter the stiffness parameter of the magnetic viscoelastic elastomer. By changing the magnetic field intensity, the stiffness of the elastomer can be adjusted to match varying disturbance frequencies, thereby maintaining optimal damping performance. This parameter adjustment capability allows the system to adapt to frequency variations without requiring complex active control mechanisms.
4Reliability
If active mass damper is used with actuator for forcibly vibrating mass, then high damping effect is achieved irrespective of frequency stability, but device complexity increases and cost increases
Solution Approach 1:
The patent applies mechanics substitution by replacing the mechanical actuator system with a magnetic field-based control system. Instead of using an actuator to forcibly vibrate the mass, the invention uses a magnetic field to adjust the stiffness of the magnetic viscoelastic elastomer, which passively provides the damping force. This substitution eliminates the need for complex actuators and control systems while maintaining damping effectiveness, thereby reducing device complexity and cost.
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 configuration enables efficient application of the magnetic field to the magnetic viscoelastic elastomer, enhancing damping effectiveness while reducing manufacturing costs and complexity, allowing for adaptive control of resonance frequencies and vibration suppression.
Implementation Method 1
an exciting coil that generates a magnetic field in accordance with an intensity of a current supplied thereto
Implementation Method 2
a magnetic viscoelastic elastomer that has a magnetic viscoelastic property varying in accordance with a magnitude of the magnetic field from the exciting coil
Implementation Method 3
arrangement of the magnetic powder in the concentrated manner in a part which largely contributes to vary the stiffness of the magnetic viscoelastic elastomer
Data Source
AI summary
An active vibration controller includes: a housing; a first magnetic member on the housing, the first magnetic member including a first tip portion extending from a first base end of the first magnetic member and including a first connecting surface extending from the base end on the first tip portion; a movable member including a second magnetic member including a second tip portion extending from a second base end of the second magnetic member and a second connecting surface extending from the second base end on the second tip portion; an exciting coil; a magnetic viscoelastic elastomer having a magnetic viscoelastic property varying according to a magnetic field magnitude between the first and second tip portions, and connects the first connecting surface to the second connecting surface. The first and second tip portions are thinner than the first and second base ends, respectively.