Semi-Rigid Fuel Cell Attachment for Stress-Buffered Connections
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Solution Overview
Problem
Existing fuel systems in vehicles, particularly aircraft, face challenges in achieving fuel efficiency due to discontinuous transitions in rigidity between rigid fuel lines and flexible fuel cells, which can lead to stress-related damage and leaks.
Innovation Solution
A flexible fuel cell system is developed with semi-rigid attachment structures formed by stitching yarns through fittings on a flexible substrate and encapsulating them with a polyurethane resin, using a computer numerical control process to create a buffer against stress and reduce material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid fuel lines are directly connected to flexible fuel cells, then structural strength is improved, but stress concentration and damage risk increase due to discontinuous rigidity transition
Solution Approach 1:
The patent applies parameter changes by creating a gradient in rigidity from the rigid fuel line through the attachment structure to the flexible fuel cell. The semi-rigid attachment structure with stitched yarns and encapsulant provides intermediate rigidity values, creating a continuous transition that reduces stress concentration while maintaining structural strength.
Solution Approach 2:
The semi-rigid attachment structure acts as an intermediary between the rigid fuel line and flexible fuel cell. This intermediate structure with controlled rigidity buffers the abrupt transition, distributing stresses and preventing damage at the connection interface.
2Ease of manufacture
If traditional attachment methods are used, then ease of manufacture is improved, but material usage and weight increase
Solution Approach 1:
The patent uses flexible substrates and thin encapsulant layers to create the attachment structure. The encapsulant forms a thin protective layer that bonds the fitting to the flexible substrate, minimizing material usage while maintaining structural integrity and reducing overall weight.
Solution Approach 2:
The attachment structure employs composite materials including stitched yarns (organic fibers), encapsulant (polymer resin), and flexible substrate materials. This composite approach provides optimized strength-to-weight ratio, combining the advantages of different materials to reduce overall weight while maintaining manufacturing feasibility.
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 solution enhances the reliability of fuel cell connections by buffering stress, reducing the risk of damage and leaks, while minimizing weight and material usage, thereby improving fuel efficiency and resistance to ballistic projectiles.
Implementation Method 1
the encapsulant including a third fuel-tolerant material, the third fuel-tolerant material chemically bonded to the second fuel-tolerant material and the first fuel-tolerant material
Implementation Method 2
the sheath includes a bicomponent filament having a melting point in a range of 50° C. to 200° C.
Data Source
AI summary
In an embodiment, a fuel cell includes: a flexible substrate including a first fuel-tolerant material; a fitting on the flexible substrate, the fitting including first openings extending through an outer portion of the fitting; a primer coating on the outer portion of the fitting, the primer coating including a second fuel-tolerant material; first yarns strung through the first openings of the fitting, the first yarns stitched into the flexible substrate; and an encapsulant encapsulating the first yarns, the primer coating, and the outer portion of the fitting, the encapsulant disposed on the flexible substrate, the encapsulant including a third fuel-tolerant material, the third fuel-tolerant material chemically bonded to the second fuel-tolerant material and the first fuel-tolerant material.