Buffered Centering Fastener Structure for Wind Turbine Misalignment
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Solution Overview
Problem
In wind turbines, connecting fasteners like bolts or studs experience fatigue failure due to stress concentration at positioning and connecting portions, often caused by misalignment, leading to reduced stability and reliability.
Innovation Solution
A centering fastener comprising a connecting body, a buffer lining, and a centering member, where the buffer lining coats the non-threaded portion and the centering member coats the buffer lining, forming a layered structure that reduces stress concentration by absorbing external forces, with the centering member having a strength greater than or equal to the connecting body and made from fiber-reinforced resin matrix composite materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a one-piece structure with varied cross-section is used as positioning segment, then positioning function is improved, but stress concentration occurs at the joint leading to reduced fatigue strength
Solution Approach 1:
The patent divides the positioning segment into multiple independent layers: a centering member (first layer), a buffer lining (second layer), and the connecting body (third layer). This segmentation allows each layer to perform its specific function independently, preventing stress concentration at joints while maintaining the positioning function. The centering member provides positioning, the buffer lining absorbs stress, and the connecting body provides structural support.
Solution Approach 2:
The patent employs composite material structure by combining different materials for each layer. The centering member can be made of metal or composite material, the buffer lining is made of elastic or damping material, and the connecting body is made of high-strength material. This composite approach allows optimization of each layer's properties to address both positioning and fatigue strength requirements simultaneously.
2Strength
If high-strength connecting bolts are used to withstand large variable loads, then fatigue strength is improved, but misalignment causes bending stress that reduces the effectiveness of the high-strength bolts
Solution Approach 1:
The patent incorporates a buffer lining as a second layer between the centering member and the connecting body. This buffer lining is made of elastic or damping material that beforehand cushions and absorbs bending stresses caused by misalignment, preventing these stresses from reaching the high-strength connecting bolts and reducing their effectiveness.
Solution Approach 2:
The buffer lining acts as an intermediary element between the centering member and the connecting body. It mediates the transmission of forces, absorbing and dampening bending stresses from misalignment before they reach the connecting bolts, thereby protecting the high-strength fasteners from harmful stress concentrations.
Data Source
AI summary
A centering fastener, a method for manufacturing the centering fastener, a method for using the centering fastener and a wind turbine are provided. The centering fastener includes a connecting body, a buffer lining and a centering member, the connecting body is a columnar body and includes a connecting portion and a non-threaded portion; the buffer lining has a cylindrical shape and covers at least part of the non-threaded portion; the centering member covers an outer surface of the buffer lining, and, at least at a portion corresponding to the buffer lining, the non-threaded portion is separated from the centering member.