Segmented Wind Turbine Rotor Blades With Shear-Bolt Joints
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Solution Overview
Problem
Existing segmented rotor blades for wind turbines face challenges in transport due to precision requirements for screw connections, leading to increased production costs, space requirements, and limited interchangeability, while current connection technologies do not provide sufficient load-bearing capacity for long blades, especially when segmented closer to the blade root, resulting in aerodynamic losses.
Innovation Solution
A connecting arrangement using transverse bolts and shear connection elements, with cross-bolts and connecting plates, allows spar elements to be joined without direct contact, enabling high connection strength and reduced mass, using fiber-composite materials and metal or fiber-metal laminates for enhanced stability and aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If insert screw connections are used to connect rotor blade segments, then force-fitting and form-fitting connection is achieved, but manufacturing precision requirements increase significantly
Solution Approach 1:
The patent introduces a connecting element with connecting arms as an intermediary component between the two spar elements. This connecting element mediates the connection by providing bushings that receive cross bolts, allowing the spar elements to be connected without requiring direct high-precision alignment between their own bushings. The connecting element absorbs the alignment tolerances and enables robust connection.
Solution Approach 2:
The connection system is segmented into distinct functional components: spar elements, connecting element with connecting arms, bushings, and cross bolts. This segmentation allows each component to be manufactured and assembled separately, with the connecting element serving as a modular interface that simplifies the overall alignment requirements.
2Length of moving object
If segmented rotor blades are used to reduce transport constraints, then transportability improves, but connection technology complexity increases
Solution Approach 1:
The connecting element is inserted into the joint region between two rotor blade segments, with connecting arms extending into the respective spar elements. This nested arrangement allows the connection technology to be integrated within the existing blade structure without requiring external mounting hardware or complex external connection mechanisms.
Solution Approach 2:
The spar elements are prepared in advance with recesses and opening arrangements during blade manufacturing. The connecting element is designed to fit into these pre-prepared features, allowing for simplified assembly at the joint location without requiring complex field modifications or adjustments.
3Strength
If segmentation position is shifted toward blade tip to maintain load-bearing capacity, then connection strength is maintained, but aerodynamic losses increase due to enlarged profile
Solution Approach 1:
The connecting element is designed with varying arm lengths and structural characteristics tailored to the specific load conditions at different blade positions. The connecting arms can be optimized locally to provide sufficient strength while minimizing the enlargement of the blade profile, thereby reducing aerodynamic losses.
Data Source
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AI summary
The invention relates to a segmented rotor blade for wind turbines with at least two blade segments extending in opposite directions from a joint in a longitudinal direction, each blade segment having at least one internal spar element forming a structural element of the rotor blade, characterized in that a) the first spar element of the first blade segment and the second spar element of the second blade segment are joined together at the joint with their end faces by means of a connecting arrangement, b) wherein the connecting arrangement comprises a plurality of connecting assemblies, each connecting the spar elements to one another, c) wherein each connecting assembly comprises a first transverse bolt, a second transverse bolt and at least one connecting tab, which has a first tab opening and a second tab opening at its ends,d) wherein in each connecting assembly the first transverse bolt is guided transversely to the longitudinal direction of the rotor blade through a spar opening in the first spar element and the first tab opening of the connecting tab, and the second transverse bolt is guided transversely to the longitudinal direction of the rotor blade through a spar opening in the second spar element and the second tab opening of the connecting tab, such that the connecting tab connects the spar elements to each other, and e) wherein at least the first transverse bolt of a first connecting assembly and the second transverse bolt of a second connecting assembly opposite the first connecting assembly are connected to each other via at least one first shear connecting element.