Rotatable Spring Tuned Mass Damper for Vibration Control
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Solution Overview
Problem
Existing tuned mass dampers in fiber-web machines, particularly in two-drum or belt-type winders and reeling drums, face challenges in accurately controlling vibration due to insufficient damping and resonance issues, requiring improved adjustability and accuracy in frequency tuning.
Innovation Solution
An adjustable tuned mass damper comprising a body part and a mass element connected by at least two spring elements, where at least one spring element is rotatable with a varying second moment of area in different directions, allowing for precise adjustment of stiffness and synchronization of rotational positions for enhanced damping control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the position of the mass on a vibrating rod is changed to adjust the frequency, then the tuning can be modified during operation, but the clearance between parts becomes large and adjustment accuracy deteriorates
Solution Approach 1:
The patent changes the physical parameter of the spring element by rotating it around its longitudinal axis. This rotation alters the second moment of area of the spring's cross-section, thereby changing the stiffness parameter of the damper. This allows frequency adjustment without requiring large clearances or compromising precision, as the adjustment is achieved through rotational movement rather than positional displacement.
2Adaptability or versatility
If the magnitude of the mass is changed to adjust the frequency, then the tuning can be modified during operation, but the device complexity increases
Solution Approach 1:
Instead of changing the mass magnitude, the patent changes the stiffness parameter by rotating the spring element. This approach maintains the same mass while achieving frequency adjustment through altering the spring's second moment of area. The mechanism is simpler than mass adjustment systems because it only requires rotational capability rather than complex mass relocation or replacement mechanisms.
3Measurement precision
If the second moment of area of the spring element is varied by rotation, then the stiffness can be precisely adjusted, but the device complexity increases due to rotational mechanism
Solution Approach 1:
The patent introduces a dynamic element (rotational capability) to the spring mechanism, allowing the second moment of area to be varied by rotating the spring around its longitudinal axis. This dynamic adjustment mechanism provides precise control over stiffness while maintaining relatively simple construction, as the rotation can be achieved through straightforward mechanical means without complex linkages or actuators.
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 accurate and effective vibration attenuation by allowing continuous adjustment of the damper's stiffness, improving damping control and reducing resonance vibrations in fiber-web machines, particularly in rolls and drums, ensuring stable web winding operations.
Implementation Method 1
a mass element (16) connected to the body part (12) by at least two spring elements (20)
Implementation Method 2
said at least one rotatable spring element has its second moment of area different in different directions cross sectional plane at least at one longitudinal location
Implementation Method 3
A tuned mass damper is a generally known arrangement for attenuating harmonic vibration
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
The present invention relates to an adjustable tuned mass damper (10) comprising a body part (12) and a mass element (16) connected with the body part by at least two spring elements (20,40), in which least one (20) of said at least two spring elements is arranged rotatable in respect to the body part and the mass element and that the at least one rotatable spring element (20) has its second moment of area different in different directions cross sectional plane at least at one longitudinal location.