Curved Composite-Metal Wall Structure for Cryogenic Tightness
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Solution Overview
Problem
Existing composite material walls are not hermetic for liquids or gases, especially in curved applications, and face issues with galvanic corrosion and thermal expansion mismatch.
Innovation Solution
A curved wall design comprising alternating layers of carbon fiber composite and titanium-based metal strips, with the metal strips covering at least 80% of the surface and having specific thickness and width, to create a molecular barrier and maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal layer is added between composite layers to improve tightness, then hermeticity is improved, but device complexity increases
Solution Approach 1:
The patent applies composite materials by combining metal strips (titanium-based) with carbon fiber composite layers to create a multi-layered structure. This composite construction provides both the hermeticity needed for liquid/gas containment and the structural integrity required for curved geometries, resolving the contradiction between improved tightness and increased structural complexity.
Solution Approach 2:
The metal layer is segmented into discrete strips rather than a continuous sheet. These strips are applied in specific patterns (covering at least 80% of the surface) to achieve the required hermeticity while minimizing material usage and structural complexity. The segmentation allows the metal to conform to curved surfaces without requiring a complete continuous layer.
2Area of stationary object
If wide metal foil is used to cover the curved surface, then coverage is improved, but the foil creates folds when following the curve
Solution Approach 1:
The metal layer is divided into multiple narrow strips (width between 2 and 200 mm) that can individually conform to the curved surface geometry. This segmentation prevents folding and maintains surface smoothness while achieving comprehensive coverage through strategic placement of multiple strips.
Solution Approach 2:
The metal strips are applied with specific local characteristics - narrow width for flexibility and curve conformity, sufficient coverage (at least 80% of surface) for hermeticity. This local optimization allows each strip to follow the curve smoothly while collectively providing the required surface coverage.
3Strength
If thick metal layer is used to improve strength, then structural integrity is improved, but the wall becomes heavier
Solution Approach 1:
The metal strips use optimized thickness parameters (between 1 and 500 μm) that provide sufficient structural integrity and hermeticity while minimizing weight. The specific thickness range allows the metal to function as an effective barrier and structural element without excessive mass, achieving the desired strength-weight balance.
Solution Approach 2:
The combination of thin metal strips with carbon fiber composite layers creates a composite structure where each material performs its optimal function. The metal provides hermeticity and structural reinforcement, while the composite layers provide structural bulk and weight efficiency, achieving high strength-to-weight ratio.
4Reliability
If different materials are used for composite and metal layers, then functional properties are improved, but galvanic corrosion may occur
Solution Approach 1:
The patent specifies using titanium-based material for the metal strips, which has specific material parameters (chemical composition, electrical potential) that are compatible with carbon fiber composites. This material selection prevents galvanic corrosion by ensuring compatible electrochemical properties while maintaining the functional benefits of the composite-metal structure.
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
The design provides enhanced tightness, resistance to overload, and thermal stability, suitable for cryogenic applications with reduced risk of galvanic corrosion and micro-cracking.
Implementation Method 1
The presence of a metal layer between the composite layers creates a barrier for molecules, which increases the tightness of the wall
Implementation Method 2
Because of its ductility, the titanium-based material makes the rupture of the stress introduction point more progressive in case of an overload on the curved-wall
Implementation Method 3
The combination of the carbon fibers and the titanium-based material is especially interesting because there is no galvanic corrosion between these materials
Implementation Method 4
their coefficients of thermal expansion are close. This is especially interesting for cryogenic applications where micro cracks may appear, impeding tightness
Data Source
AI summary
The present disclosure relates to a curved wall comprising an alternation of metal and composite layers, and to a method to produce it. The metal layer is made of aligned metal strips and can thus conform to any shape of the curved wall.