Impulse Damper Layout for Second-Frequency Tower Vibration
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Solution Overview
Problem
Existing impulse dampers are less effective for damping the second natural frequency of tall, slender structures like wind turbines, as they are primarily designed to address the first natural frequency, which occurs higher up in the structure.
Innovation Solution
A novel impulse damper with elastic stop-damping elements on both the damper and system sides, allowing the damper mass to move horizontally and generate an impulse against the direction of movement, effectively damping the second natural frequency by distributing the stop load across multiple elements and optimizing friction and damping properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an impulse damper is designed to dampen the first natural frequency of the tower, then it is effective for vibrations occurring in the top quarter to fifth of the tower, but it is less suitable for damping the second natural frequency which occurs in the middle or at half to two thirds of the tower height
Solution Approach 1:
The patent applies local quality by positioning the impulse damper at a specific height (middle section, 40-80% of tower height) rather than at the top, and by designing the stop devices with specific geometric parameters (radius ratio between 0.3-0.7) tailored for second natural frequency damping. This localized adaptation makes the damper effective for the target frequency while maintaining structural integration.
2Force
If the damper mass hits the support structure directly, then a strong impulse is generated against the direction of movement, but the stop load is concentrated on a single point causing high stress
Solution Approach 1:
The patent segments the stop load by introducing multiple damping elements (at least 3, preferably 6-12) distributed around the circumference of the stop devices. This distributes the impact force from the damper mass across multiple contact points, reducing stress concentration while maintaining the overall impulse force needed for effective damping.
Solution Approach 2:
The patent introduces damping elements (elastomer elements, spring elements, or friction elements) as intermediaries between the damper mass and the support structure. These elements mediate the impact by providing a controlled deformation zone that dissipates energy through friction and heat, reducing the peak stop load while maintaining damping effectiveness.
3Stress or pressure
If damping elements are used to distribute the stop load, then stress concentration is reduced, but energy dissipation through friction and heat increases
Solution Approach 1:
The patent converts the harmful energy dissipation through friction and heat into a beneficial effect by using friction elements as damping mechanisms. The friction between the friction elements and the support structure during impact provides additional damping force while distributing the stop load, transforming energy loss into useful vibration suppression.
4Device complexity
If the damper is integrated into the support structure without a separate housing, then cost and complexity are reduced, but the installation space and structural integration requirements increase
Solution Approach 1:
The patent merges the impulse damper components directly into the support structure by integrating the damper mass, bearing elements, and stop devices with the tower structure. This eliminates the need for a separate damper housing and simplifies installation, while the modular design of the damping elements allows for flexible integration at different tower heights.
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 effectively reduces vibrations at the second natural frequency, minimizing structural stress and noise pollution while reducing energy dissipation through friction and heat management, and can be integrated into the structure without a separate damper housing, offering cost and performance advantages.
Implementation Method 1
The damping elements (7), (7') can for example be elastomer elements, spring elements or friction elements
Implementation Method 2
The damping elements (7), (7') can for example be elastomer elements, spring elements or friction elements
Implementation Method 3
When the moving damper mass hits elements of the support structure or the system, an impulse is generated against the direction of movement of the system
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a novel impulse damper for reducing, in particular, extreme vibrational events, in tall, narrow structures, more particularly wind turbines. The impulse damper according to the invention operates on the impact-damping principle and is particularly suitable for damping the second natural frequency of the installation, preferably of the tower of a wind turbine.