Composite Skin and Hollow Stringers for Lightweight Impact Resistance
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Solution Overview
Problem
The challenge is to produce structural components for space vehicles or modules using composite materials that provide adequate protection against compression, sudden accelerations, and impact from space debris while adhering to weight limits to reduce costs.
Innovation Solution
A method involving the application of stiffening stringers on the external surface of a composite skin using an Inner Mould Line process, with expandable inserts to maintain cavities during curing, ensuring the stringers form the external structure, enhancing resistance to impacts and maintaining lightweight properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal components are used to provide greater strength, then the strength parameter is improved, but the weight increases and total costs increase
Solution Approach 1:
The patent applies composite materials (carbon fiber reinforced polymer) to manufacture stiffening stringers for the fuselage. This resolves the contradiction by providing high strength-to-weight ratio characteristics of composite materials, achieving both strength requirements and weight reduction goals simultaneously, eliminating the need to choose between metal strength or composite weight
2Weight of moving object
If composite material is used to reduce overall weight, then the weight parameter is improved, but the resistance to compression and impact may be insufficient
Solution Approach 1:
The patent segments the fuselage structure into skin panels and stiffening stringers. The stringers are separate structural elements that provide compression and impact resistance, while the skin provides the lightweight envelope. This segmentation allows each component to be optimized for its specific function, resolving the contradiction between weight and strength
Solution Approach 2:
The patent applies local quality by concentrating stiffening stringers at specific locations where compression and impact resistance is most needed, rather than uniformly reinforcing the entire fuselage. This allows weight optimization in non-critical areas while maintaining strength where required
3Ease of manufacture
If stringers are positioned on the internal surface of the skin, then the manufacturing process is simplified, but the resistance to impacting bodies is reduced
Solution Approach 1:
The patent inverts the conventional arrangement by positioning stringers on the external surface of the fuselage skin rather than the internal surface. This inversion allows stringers to directly face and resist impacting bodies (space debris, micrometeorites) while maintaining manufacturing feasibility through adaptive tooling and bonding processes
4Ease of manufacture
If stringers are made with open profile cross-section, then the manufacturing process is simpler, but the resistance to compression is reduced
Solution Approach 1:
The patent employs curved or closed profile cross-sections for the stiffening stringers (such as circular, oval, or polygonal sections) rather than open profiles. These curved/closed sections provide superior compression resistance due to their geometric efficiency in distributing compressive loads, while the manufacturing complexity is managed through standardized tooling and automated laying processes
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 method results in a structural component with improved resistance to compression and impacts, meeting weight limits while providing enhanced protection for payloads, suitable for space vehicles.
Implementation Method 1
The assembly thus formed then undergoes a curing process by applying high pressure and temperature so as to cure the composite material, compact the above-mentioned layers together and have the stringers join the skin
Data Source
AI summary
A method to manufacture a structural component in composite material reinforced with stiffening stringers and comprising a skin and plurality of stringers having a hollow section fixed to said skin. The method comprising: a) laminating a plurality of first layers of composite material onto an external surface of a cure tool, b) laminating pluralities of second layers of composite material on longitudinal hollow expandable inserts, c) positioning each reinforcing element on a face of a second skin, d) holding each reinforcing element on the face of the second skin; e) housing the tool, skin and reinforcing elements inside a vacuum bag; and f) compacting together the first layers forming the skin with the second layers forming the stringers; g) housing skin and reinforcing elements in a further vacuum bag; and h) sealing the further vacuum bag; and i) applying preset temperature and pressure to the outside of the vacuum chamber.