Radially Adjustable Ring Stiffener for Wind Turbine Towers
Solution Overview
Problem
Conventional wind turbine towers face challenges in balancing reduced material costs with structural strength, particularly in larger turbines, where thinner walls increase flexibility and vulnerability to buckling, and existing reinforcement methods like welding can compromise fatigue strength.
Innovation Solution
A radially adjustable ring stiffener is used to reinforce tubular structures by expanding to fit within the tower, engaging with the inner surface through friction, without welding or fasteners, thereby increasing structural strength without reducing fatigue resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the wall thickness of tower sections is reduced to minimize material cost, then material cost decreases, but the strength and buckling resistance of the tower deteriorates
Solution Approach 1:
The ring stiffener is inserted inside the tubular tower structure, nesting a reinforcing element within the existing tower wall. This allows the tower to maintain thinner walls for cost efficiency while containing an internal reinforcement structure that provides the necessary buckling resistance without adding external bulk
Solution Approach 2:
Ring stiffeners are installed at specific critical locations along the tower where buckling risk is highest, rather than uniformly thickening the entire tower wall. This localized reinforcement approach minimizes material usage while providing strength exactly where needed
2Strength
If ring stiffeners are welded to the tower walls to reinforce vulnerable sections, then buckling resistance increases, but fatigue strength deteriorates due to welding hotspots
Solution Approach 1:
The ring stiffener is extracted from the welding process entirely. Instead of being attached through thermal welding that creates hotspots, the stiffener is installed as a separate internal component that engages with the tower wall through mechanical friction and radial pressure, eliminating the harmful thermal effects of welding
Solution Approach 2:
The ring stiffener acts as an intermediary element that transfers loads between the internal and external surfaces of the tower wall without direct welding. It engages the tower wall through friction and radial pressure, providing reinforcement while avoiding direct metallurgical bonding that would create fatigue-sensitive weld zones
3Strength
If thicker tubular sections are used in critical areas to reduce mass without compromising strength, then structural strength improves, but material cost and installation complexity increase
Solution Approach 1:
Rather than manufacturing thicker tower sections, the invention nests thinner-walled tower sections with internal ring stiffeners. This achieves the same structural strength as thicker sections but with less material, as the stiffeners are separate components installed inside the existing tower structure
Solution Approach 2:
The reinforcement system is segmented into separate ring stiffener components that can be individually manufactured, transported, and installed at specific locations along the tower. This allows optimization of material usage by placing reinforcement only where structurally necessary rather than uniformly thickening the entire tower
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 method effectively reinforces vulnerable areas of wind turbine towers, enhancing structural integrity and buckling resistance while maintaining fatigue strength, and can be applied to existing turbines through in-situ installation.
Implementation Method 1
engaging an inner surface of the tubular wind turbine structure with a radial force that holds the ring stiffener at the reinforcement position by means of friction between the ring stiffener and the tubular wind turbine structure
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
An aspect of the invention relates to a method of reinforcing a tubular wind turbine structure using a radially adjustable ring stiffener. The ring stiffener comprises a pair of adjacent ring segments coupled together by a coupling means configured to permit radial adjustment of the ring stiffener by varying an intersegmental separation between adjacent ends of those ring segments. The method comprises: positioning the ring stiffener at a reinforcement position within the tubular wind turbine structure; and adjusting the intersegmental separation between the pair of adjacent ring segments to increase the radius of the ring stiffener; and thereby to engage an inner surface of the tubular wind turbine structure with a radial force that holds the ring stiffener at the reinforcement position by means of friction between the ring stiffener and the tubular wind turbine structure.