Composite Mandrel Foam Core Carbon Fiber Resin
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Solution Overview
Problem
Prior art mandrels, whether made of wood or metal, suffer from instability issues, with wooden mandrels causing non-uniformity in composite products and metallic mandrels experiencing thermal instability due to ambient temperature changes.
Innovation Solution
A composite mandrel is constructed using a high-density, closed-cell polyurethane foam core overlaid with multiple layers of carbon fiber-reinforced resin and an outer layer of glass fiber-reinforced resin, providing dimensional and thermal stability, and allowing for complex shapes to be formed through the use of splice plates and CAD manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wooden mandrels are used, then ease of manufacture is improved, but dimensional stability deteriorates causing non-uniformity in composite products
Solution Approach 1:
The mandrel uses a composite structure combining foam core with carbon fiber-reinforced resin layers. This composite material provides both ease of manufacture (foam can be easily shaped) and high dimensional stability (carbon fiber reinforcement prevents deformation), resolving the contradiction between manufacturability and precision.
2Manufacturing precision
If metallic mandrels are used, then dimensional stability is improved, but thermal stability deteriorates due to ambient temperature changes
Solution Approach 1:
The foam core combined with carbon fiber reinforcement creates a material with low thermal conductivity and high thermal stability. The carbon fiber layer acts as a thermal barrier while maintaining dimensional stability, allowing the mandrel to resist temperature changes better than metallic mandrels, thus improving reliability in varying thermal environments.
3Strength
If solid wood or metal mandrels are used, then structural strength is achieved, but weight is excessive affecting handling and automation
Solution Approach 1:
The mandrel uses a foam core that provides lightweight structure, with carbon fiber-reinforced resin layers applied only where structural strength is needed. This localized reinforcement approach maintains necessary strength while minimizing overall weight, enabling easier handling and automation compared to solid wood or metal mandrels.
4Device complexity
If traditional mandrels are used, then simplicity of structure is maintained, but stiffness is insufficient causing wrinkles in composite preforms
Solution Approach 1:
The carbon fiber-reinforced resin layers provide high stiffness to the mandrel structure, preventing wrinkles in composite preforms during manufacturing. The multi-layer composite construction achieves the required stiffness without significantly increasing structural complexity, as the layers are applied in a systematic manner over the foam core.
Data Source
AI summary
A mandrel and method of making a mandrel for use as a substrate in the manufacture of woven or braided articles. The mandrel may have an inner core of foam; at least a first layer of carbon fiber-reinforced resin, and an outer layer of glass fiber-reinforced resin. The foam core may be a high density, closed cell polyurethane foam that is formed of a desired size and shape. The fibers in the first layer and outer layer may be, for example, chopped fibers, continuous longitudinally aligned fibers, circumferentially wound fibers, obliquely aligned fibers, or the fibers may have a woven or braided pattern. Multiple mandrels may be joined together to form complex mandrel shapes such as curves, ovals, and circles.