Elongated Composite Structure Manufacturing with Flexible Foil Interface
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Solution Overview
Problem
The challenge lies in manufacturing large elongated composite structures, such as wind turbine blades, where achieving a perfect fit between separate blade sections for assembly is difficult, leading to transportation and assembly issues due to the current methods of manufacturing shell parts in separate moulds and subsequent gluing, which can result in imperfect joints.
Innovation Solution
The method involves forming first and second longitudinal composite structure sections in the same mould, using a thin flexible foil to separate the fibre lay-ups at the overlap area, ensuring a perfect complementary fit, allowing for easy transportation and assembly of the sections, which are then interconnected with a glue joint or mechanical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If separate blade sections are manufactured in separate moulds, then transportation and handling are simplified, but manufacturing precision and fit quality deteriorate
Solution Approach 1:
The blade is divided into multiple sections that can be manufactured separately and assembled later. Each section is manufactured in its own mould, allowing for easier transportation and handling of individual sections while maintaining the ability to achieve precise fits through the manufacturing process design
Solution Approach 2:
A vacuum bag is used as an intermediary element during the manufacturing process. The vacuum bag allows sections to be formed with precise dimensional control and surface quality, ensuring that when sections are separated and transported, they can be reassembled with high fit quality. The vacuum bag acts as a mediator between the mould and the final composite section
2Ease of operation
If sections are manufactured separately and assembled, then ease of assembly is improved, but reliability of the joint deteriorates
Solution Approach 1:
The blade is segmented into multiple sections that can be independently manufactured and then assembled. This segmentation enables easier assembly operations while the design of the segmentation interfaces ensures that joint reliability is maintained through proper bonding surfaces and alignment features
Solution Approach 2:
Vacuum technology is employed during the manufacturing process to ensure high-quality bonding surfaces and precise dimensional control of each section. The vacuum infusion process ensures thorough resin impregnation of fibres, creating strong, reliable sections that will form dependable joints when assembled
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
This approach ensures a precise fit between composite structure sections, facilitating a strong glue joint or mechanical connection, thereby enhancing the structural integrity and ease of transportation and assembly of elongated composite structures like wind turbine blades.
Implementation Method 1
During the manufacturing process, liquid polymer, also called resin, is filled into a mould cavity, in which fibre material, also called fibre lay-up, has been previously inserted and where vacuum is generated in the mould cavity hereby drawing in the polymer
Implementation Method 2
From the inlet channels, the polymer disperses in all directions in the mould cavity due to the negative pressure as the flow front moves towards the vacuum channels
Data Source
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AI summary
A method of manufacturing an elongated composite structure having two separate longitudinal composite structure sections, where said method comprises the following steps: providing a rigid mould part (13) having a first forming surface (14) with a contour defining an outer surface of the elongated composite structure, arranging a first fibre lay-up (15) in a first longitudinal section (16) of the first mould part (13), arranging a first flexible foil (18) over a first crosswise edge area (17) of the first fibre lay-up (15), arranging a second fibre lay-up (20) in a second longitudinal section (21) of the mould part (13) so as to overlap the crosswise edge area (17) of the first lay-up (15) and thereby the first flexible foil (18) in an overlap area (22) forming an interface between the fibre lay-ups (15,20), arranging a second flexible foil (23) over the second fiber lay-up (20), providing polymer to the fibre lay-ups (15,20) and allowing the polymer to cure.