Ultra-Thin Pre-Preg Sheets for Complex Geometry Composites
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Solution Overview
Problem
Existing pre-preg sheets are thick, cumbersome, and costly to produce complex geometry composite materials, leading to draping difficulties, resin splitting, and reduced mechanical properties due to excessive resin and crimp angles, especially with ultra-high modulus carbon fibers.
Innovation Solution
Development of ultra-thin pre-preg sheets with unidirectional spread fibers, low crimp angles, and a just-sufficient resin pattern for quick dispersion, allowing for efficient draping and reduced resin distance between plies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional dry thin textile reinforcement sheets are used, then the thickness is reduced to about 0.15 to 0.2 mm, but the sheets are relatively thick and tend to split laterally due to cracking of resin when forced into complex geometries
Solution Approach 1:
The patent changes the physical and chemical parameters of the matrix material by using a thermoplastic polymer with specific viscosity characteristics and adding a lubricant. This creates a more ductile and flexible pre-preg that can be formed into complex geometries without resin cracking or splitting, while maintaining ultra-thin dimensions.
Solution Approach 2:
The patent creates a composite system by combining textile reinforcement with a specific thermoplastic matrix formulation that includes lubricant additives. This composite structure provides both the thinness needed for complex geometries and the enhanced ductility to prevent resin cracking during forming operations.
2Stability of the object's composition
If four unidirectional continuous fibre tows are plied in mutually different multiaxial orientations to produce in-plane isotropic properties, then the thickness increases to at least 0.6 to 1 mm
Solution Approach 1:
The patent uses ultra-high modulus carbon fibres with specific dimensional parameters and a thermoplastic matrix with controlled viscosity and lubricant content. This allows the fabrication of in-plane isotropic pre-pregs with thickness less than 0.5 mm, overcoming the traditional limitation where four plied tows resulted in 0.6 to 1 mm thickness.
3Reliability
If relatively higher content of resin is used in pre-preg sheets to reduce splitting, then the fibre volume-fraction is lowered and areal weight increases
Solution Approach 1:
The patent optimizes the matrix material parameters by using a thermoplastic polymer with specific viscosity and adding lubricant. This formulation provides adequate resin content to prevent splitting during forming while maintaining high fibre volume fraction and low areal weight, as the lubricant-enhanced matrix requires less overall resin to achieve the same crack-prevention effect.
4Stability of the object's composition
If fibrous tows are stacked in mutually different orientations to create in-plane isotropic composite material, then crimp angle increases to about 4° to 8°, but low crimp angle below 3° is needed for high in-plane stiffness
Solution Approach 1:
The patent uses ultra-thin reinforcement layers with optimized fibre tow dimensions and a thermoplastic matrix with controlled viscosity and lubricant content. This combination enables the fabrication of in-plane isotropic pre-pregs with crimp angle below 3°, thereby achieving high in-plane stiffness while maintaining isotropic mechanical properties.
Data Source
AI summary
Novel ultra-thin unidirectional pre-preg tapes are disclosed. They can be used to produce ultra-thin woven, bias, multiaxial, chopped-oriented etc. types of pre-pregs. These ultra-thin pre-pregs enable production of composite material products with well-controlled dimensional tolerances and smooth/even surfaces. Further, they render the production of composite material products relatively simpler, tidier, quicker, and economical. The obtained composite material products are relatively thinner, lighter, and mechanically higher-performing.