Surfacing Film for Composite Structures Lightning Strike Protection
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Solution Overview
Problem
Fiber-reinforced resin matrix composite laminates in aerospace and automotive applications face challenges with lightning strike protection due to lack of electrical conductivity, susceptibility to microcracking and corrosion, which affects durability and safety, especially in ungrounded composite structures.
Innovation Solution
A layered construction comprising a cured polymeric composite with a surfacing film that maintains a storage modulus similar to the bare composite, optionally including an electrically conductive layer, to enhance erosion resistance, corrosion resistance, and microcracking resistance without elevating the composite's storage modulus significantly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a surfacing film is applied to protect the composite, then corrosion resistance and erosion resistance are improved, but the storage modulus of the composite is elevated
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the surfacing film and selecting materials with specific mechanical properties. The film thickness is optimized to provide adequate corrosion and erosion protection while maintaining the storage modulus within acceptable limits (no more than 118% increase). This involves adjusting physical parameters of the protective layer to balance protection and structural integrity.
Solution Approach 2:
The patent uses composite materials by creating a layered structure consisting of the polymeric composite substrate combined with a surfacing film. This composite construction allows the system to exhibit both the protective properties of the film (corrosion and erosion resistance) and the structural properties of the composite, achieving a synergistic effect that satisfies multiple requirements simultaneously.
2Reliability
If a surfacing film is applied to protect the composite, then erosion resistance is improved, but the storage modulus of the composite is elevated
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the surfacing film and selecting materials with specific mechanical properties. The film thickness is optimized to provide adequate corrosion and erosion protection while maintaining the storage modulus within acceptable limits (no more than 118% increase). This involves adjusting physical parameters of the protective layer to balance protection and structural integrity.
Solution Approach 2:
The patent uses composite materials by creating a layered structure consisting of the polymeric composite substrate combined with a surfacing film. This composite construction allows the system to exhibit both the protective properties of the film (corrosion and erosion resistance) and the structural properties of the composite, achieving a synergistic effect that satisfies multiple requirements simultaneously.
3Reliability
If a surfacing film is applied to protect the composite, then microcracking resistance is improved, but the storage modulus of the composite is elevated
Solution Approach 1:
The patent applies parameter changes by carefully controlling the thickness of the surfacing film and selecting materials with specific mechanical properties. The film thickness is optimized to provide adequate corrosion and erosion protection while maintaining the storage modulus within acceptable limits (no more than 118% increase). This involves adjusting physical parameters of the protective layer to balance protection and structural integrity.
Solution Approach 2:
The patent uses composite materials by creating a layered structure consisting of the polymeric composite substrate combined with a surfacing film. This composite construction allows the system to exhibit both the protective properties of the film (corrosion and erosion resistance) and the structural properties of the composite, achieving a synergistic effect that satisfies multiple requirements simultaneously.
4Reliability
If an electrically conductive layer is added to the surfacing film, then electrical conductivity is improved, but the complexity of the layered construction is increased
Solution Approach 1:
The patent merges multiple functions into a single integrated layered construction. The surfacing film is combined with an electrically conductive layer (such as a metal foil or mesh) to simultaneously provide corrosion protection, erosion resistance, microcracking resistance, and electrical conductivity. This integration reduces the need for separate protective systems and simplifies the overall structure despite the multi-functional requirements.
Solution Approach 2:
The layered construction is designed with multi-functionality, where the combined structure serves multiple purposes: the surfacing film provides environmental protection (corrosion, erosion, microcracking resistance), while the integrated electrically conductive layer provides lightning strike protection and electrical conductivity. This universal design allows a single construction to fulfill multiple protective and functional requirements.
Data Source
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AI summary
A layered construction is provided having a storage modulus G't25 at 25 °C, comprising: a) a cured polymeric composite having a storage modulus G's25 at 25 °C; and b) a cured surfacing film bound thereto; wherein G't25 is not greatly elevated over G's25, typically not more than 118% of G's25. In some embodiments the cured surfacing film comprises an electrically conductive layer, typically a metal layer. In some embodiments the cured surfacing film comprises a cured epoxy resin which may optionally be a chain-extended epoxy resin and may excludes phosphorus. The resulting layered construction may display high erosion resistance, high corrosion resistance, and high resistance to microcracking. In another aspect, methods of making the subject layered constructions are provided.