Continuous-Fiber Composite Pipe Molding via Segmented Resin Transfer
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Solution Overview
Problem
The fabrication of long-length, large-diameter composite materials for OTEC cold water pipes is challenging due to the need for multiple discrete sections and mechanical joints, which reduce strength, increase weight, and complicate transportation and installation, while existing molding processes like VARTM are limited by hydrostatic pressure and void content issues.
Innovation Solution
A new Resin Transfer Molding process incorporating aspects of VARTM, using a molding region with fixed hard surfaces and soft tools, vacuum-assisted resin distribution, and continuous fiber supply to maintain fiber continuity and minimize voids, allowing for on-site fabrication of very long and wide composite articles like OTEC cold water pipes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If discrete pipe sections are molded and connected by mechanical joints, then transportation and installation become feasible, but strength is reduced and weight increases
Solution Approach 1:
The pipe is divided into multiple discrete molded sections that can be transported and installed separately, then connected through overlapping regions with mechanical joints, making the overall system feasible for transportation and installation while maintaining structural integrity through the segmentation approach
Solution Approach 2:
The pipe sections utilize composite material construction with fiber reinforcement to compensate for the strength reduction at joint regions, allowing discrete sections to be connected while maintaining overall pipe strength through the composite structure's inherent properties
2Ease of operation
If discrete pipe sections with mechanical joints are used, then transportation becomes possible, but device complexity increases
Solution Approach 1:
The pipe is divided into modular discrete sections that can be manufactured, transported, and assembled independently, with standardized joint mechanisms that reduce the complexity of handling complex geometries as a single piece
Solution Approach 2:
The pipe sections are pre-formed and pre-assembled into modules at the manufacturing site before transportation, with joints prepared in advance to simplify on-site assembly and reduce the complexity of field operations
3Manufacturing precision
If VARTM process is used for molding, then resin distribution is improved, but hydrostatic pressure causes void content issues in long articles
Solution Approach 1:
The molding process is divided into multiple discrete shots or sections, with each section molded separately under controlled vacuum conditions, preventing hydrostatic pressure buildup that would cause voids in extremely long continuous articles while maintaining resin distribution quality in each segment
Solution Approach 2:
The molding process uses periodic vacuum application and resin infusion cycles, allowing resin to be distributed uniformly through each section in controlled intervals, preventing void formation that would occur with continuous molding of extremely long articles under hydrostatic pressure
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 process enables the fabrication of continuous-fiber composite articles with improved strength and reduced complexity by maintaining fiber continuity and minimizing voids, allowing for longer, more efficient production of large-diameter pipes without the need for multiple sections and mechanical joints, thus reducing transportation and installation challenges.
Implementation Method 1
A vacuum is applied to the molding region to minimize the void content of the article
Implementation Method 2
Pressure behind the soft tool is increased by introducing additional liquid behind the soft tool
Data Source
AI summary
A process and apparatus for multi-shot, liquid-resin-molding of continuous-fiber composite articles is disclosed. The process involves the step-wise fabrication of an article wherein continuity of the fibers is maintained between the multiple workpieces of the finished composite article.