Co-curing Composite Laminates to Eliminate Fasteners
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Solution Overview
Problem
Traditional methods of fabricating composite structures using fasteners or adhesives are time-consuming, labor-intensive, and add weight, particularly in weight-sensitive applications like aircraft, and are limited by the need for tight geometrical tolerances and the use of large, expensive autoclaves for curing large or complex composite parts.
Innovation Solution
A method of integrally co-curing uncured sections of composite laminates by interleaving composite plies to form an interfacial region, which eliminates the need for fasteners and adhesives, allowing for the creation of large and complex composite assemblies without the constraints of tight tolerances and expensive autoclave processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If fasteners are used to join composite components, then the structural assembly is achieved, but the weight increases and the manufacturing process becomes time-consuming and labor-intensive
Solution Approach 1:
The patent merges multiple composite components into a single integrated structure by co-curing them together. The method involves placing uncured composite plies in overlapping relationships between components, then curing them simultaneously to create a unified monolithic structure without requiring separate fasteners or adhesives.
Solution Approach 2:
The patent applies preliminary action by preparing composite components with uncured sections that extend beyond the component boundaries before assembly. These extending uncured sections are designed to overlap with corresponding sections of adjacent components, enabling direct integration during the co-curing process.
2Strength
If adhesive is used to bond composite components, then the assembly is achieved, but the structure is limited to non-primary load applications and tight geometrical tolerances are required
Solution Approach 1:
The patent combines multiple components into a single cured structure, eliminating the need for separate bonding processes. The overlapping uncured sections are integrated directly into the component structure, creating load-bearing joints that are as strong as the components themselves rather than relying on adhesive bonds.
3Stability of the object's composition
If traditional curing process is used for large composite structures, then the structure is cured uniformly, but large expensive autoclaves are required with high construction and operation costs
Solution Approach 1:
The patent segments the curing process by allowing different sections of the composite structure to be cured at different times. Components can be pre-cured individually or in groups, then assembled with uncured sections that are cured later during the co-curing process, eliminating the need for a single large autoclave.
4Shape
If complex geometry composite structures are fabricated using traditional methods, then the components are assembled together, but the process requires separately laying up and curing individual components followed by fastening and/or adhesively bonding
Solution Approach 1:
The patent merges the laying up, assembly, and curing processes into a single integrated operation. Multiple components with uncured sections are assembled in their final configuration and then cured together in one process, eliminating the need for separate laying up and curing of individual components followed by assembly operations.
Data Source
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AI summary
A method of fabricating a composite assembly (200) may include providing a first laminate (206) and a second laminate (216) respectively formed of first and second composite plies (204, 214), and having a respective first and second cured section (208, 218) and a respective first and second uncured section (210, 220). The method (200) may further include interleaving the first composite plies (204) in the first uncured section (210) with the second composite plies (214) in the second uncured section (220) to form an interfacial region (256). The method may additionally include curing the interfacial region (256) to join the first laminate (206) to the second laminate (216) and form a unitized composite assembly (200).