Fiber-Reinforced Composite Molding with Stretchable Sheet
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Solution Overview
Problem
Manufacturing fiber-reinforced composite materials with complex three-dimensional shapes, such as curved surfaces, often results in appearance defects like fiber meandering and wrinkles due to the inability of reinforcing fibers to follow deformation during molding, especially when using prepregs with fibers oriented in specific directions.
Innovation Solution
A method involving a stack of sheet-shaped prepregs with different fiber orientations laminated with resin films, where the fiber directions are strategically arranged to facilitate pseudo-isotropic mechanical properties and ease of deformation, using a molding die with a stretchable sheet to apply tension and guide the fibers during molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a stack with pseudo-isotropic lamination is molded into a three-dimensional curved surface shape, then the mechanical properties are improved, but wrinkles and fiber meandering occur
Solution Approach 1:
The patent divides the stack into multiple regions with different lamination patterns. Specifically, it uses a combination of pseudo-isotropic lamination regions and unidirectional lamination regions, allowing each region to contribute differently to the overall performance and appearance of the molded product.
Solution Approach 2:
The patent applies different lamination configurations to different areas of the stack. By placing unidirectional lamination regions in areas prone to wrinkle formation and pseudo-isotropic lamination in areas requiring mechanical strength, it optimizes both appearance and structural properties locally.
2Manufacturing precision
If multiple paired parts are molded separately to suppress wrinkles, then the appearance quality is improved, but the working time and cost increase
Solution Approach 1:
The patent combines multiple lamination patterns into a single integrated stack structure. By designing the stack with both pseudo-isotropic and unidirectional regions in one piece, it enables molding of the entire component in a single operation, eliminating the need to separate and reassemble multiple paired parts.
Solution Approach 2:
The patent prepares the stack with pre-designed lamination patterns before molding. The strategic arrangement of different lamination types is done in advance during stack fabrication, so that the molding process itself can produce the final part with both good appearance and mechanical properties without additional operations.
3Ease of manufacture
If a tensile force is applied to the stack to promote fiber followability, then the moldability is improved, but the manufacturing steps become troublesome
Solution Approach 1:
The patent changes the structural parameters of the stack by incorporating regions with different lamination patterns. This structural modification inherently improves fiber followability during molding without requiring external tensile forces or additional manufacturing steps, as the unidirectional regions provide pathways for fiber alignment during the molding process.
4Ease of manufacture
If the stack is directly gripped with a clamp to apply tensile force, then the moldability is improved, but fiber meandering and damage occur at the gripped part
Solution Approach 1:
The patent modifies the stack structure by adding unidirectional lamination regions that inherently provide better fiber followability during molding. This structural change eliminates the need for external clamping and tensile forces, thereby preventing fiber meandering and damage at gripped locations while still achieving good moldability.
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
This approach enables the production of fiber-reinforced composite materials with excellent mechanical properties and appearance while minimizing defects like wrinkles and meandering, enhancing productivity by allowing for the creation of complex shapes without the need for excessive handling or clamping.
Implementation Method 1
a stretchable resin or rubber sheet is disposed between one die of a pair of dies constituting the molding die and the stack, and the stack is molded by the pair of dies in a state where the stretchable sheet is stretched
Data Source
Figure 1
Figure 2A~2D
Figure 3A~4
AI summary
The purpose of the present invention is to obtain a fiber-reinforced composite material having excellent appearance or mechanical characteristics, whereby a three-dimensional shape is molded with high productivity while appearance defects such as fiber meandering or wrinkling are suppressed. In this method for manufacturing a fiber-reinforced composite material, when a stack in which a plurality of sheet-shaped prepregs (X) in which a plurality of continuously arranged reinforcing fibers are impregnated with a matrix resin composition are layered in different fiber directions is molded into a three-dimensional shape by a molding die (100) provided with a lower die (110) and an upper die (112), a stretchable sheet (10) or a resin film (Y) used in the stack (12) is utilized. In this method for manufacturing a fiber-reinforced composite material, the stack may be pre-molded to obtain a preform, and the preform may be furthermore compression-molded to obtain a fiber-reinforced composite material.