Fiber Composite Joints Using Differential Cure for Hydrogen Tightness
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Solution Overview
Problem
Existing liquid hydrogen storage systems face challenges in ensuring hydrogen tightness and mechanical performance in composite tank structures due to the use of carbon fiber reinforced plastics, where traditional joining methods like rivets and bolts are not applicable, and adhesion poses safety risks.
Innovation Solution
A fiber composite material with regions of differing curing properties is used to form covalent bonds between substructures, eliminating the need for rivets, bolts, and adhesives by allowing localized uncured matrixes to form reliable joints during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional joining methods like rivets and bolts are used to ensure mechanical performance and tightness, then structural strength is improved, but the tank structure becomes leak-prone and unsuitable for hydrogen storage
Solution Approach 1:
The patent replaces mechanical joining systems (rivets, bolts) with a chemical bonding system based on covalent bonds formed through the secondary load path in the fiber reinforcement. The fiber orientation and resin flow are controlled to create chemical bonds that provide both mechanical strength and hydrogen tightness, eliminating the need for mechanical fasteners that compromise tank integrity.
Solution Approach 2:
The patent utilizes composite material design with specifically oriented fiber reinforcements to create a secondary load path that enables covalent bonding between substructures. The composite structure incorporates fibers arranged to provide both structural support and bonding functionality, integrating joining capabilities directly into the composite material system rather than using separate fastening components.
2Ease of manufacture
If adhesive bonding is used to join substructures, then assembly is simplified, but safety risks increase due to potential bonding failures
Solution Approach 1:
The patent replaces adhesive bonding with a covalent bonding mechanism formed through the secondary load path in the fiber reinforcement. This eliminates the need for separate adhesive materials and processes, while providing superior joint reliability through direct chemical bonds integrated into the composite structure itself.
Solution Approach 2:
The patent merges the structural load-bearing function with the joining function by designing the fiber reinforcement to provide a secondary load path that creates covalent bonds between substructures. This integration eliminates the need for separate adhesive layers and combines structural integrity with joint formation in a single system.
3Reliability
If one-piece production is used to ensure tank integrity, then hydrogen tightness is improved, but manufacturing complexity increases for large and complex structures
Solution Approach 1:
The patent divides the tank into multiple substructures that can be manufactured separately using standard composite manufacturing processes. The segmented approach allows for modular production, easier handling, and standardized manufacturing techniques while maintaining overall tank integrity through the covalent bonding of substructures via the fiber secondary load path.
Solution Approach 2:
The patent uses composite material design with integrated fiber orientations to enable the segmentation of large tanks into manageable substructures. The composite structure incorporates fibers that provide both structural support and bonding capabilities, allowing segmented construction without compromising the integrity that would otherwise require one-piece production.
4Weight of moving object
If thin laminates are used to reduce tank weight, then weight ratio is improved, but mechanical performance decreases requiring thicker sections for strength
Solution Approach 1:
The patent optimizes composite material design by incorporating a secondary load path through specifically oriented fiber reinforcements. This allows thin laminates to achieve enhanced mechanical performance through the additional load-bearing capacity provided by the fiber orientation, maintaining weight reduction while improving strength and enabling reliable covalent bonding at joint interfaces.
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 method enables high-performance, tight, and reliable joints in complex composite structures, enhancing mechanical performance and ensuring hydrogen tightness without the use of additional fastening methods, particularly suitable for liquid hydrogen tanks.
Implementation Method 1
co-curing the second region of the first substructure and the second region of the second substructure after contacting to form the composite structure... establishing a chemical or covalent bond between the regions thereby forming a highly reliable and tight joint
Data Source
AI summary
A fiber composite material containing at least one layer of reinforcing fibers embedded in a polymer matrix, with the polymer matrix being formed by a curable resin and including at least one first region having a first curing property of the resin and at least one second region having a second curing property of the resin, wherein the at least one first curing property is different from the at least one second curing property, a method of manufacturing a composite structure, and a composite structure manufactured in the method.