Fiber Ply Preform for Composite Parts
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Solution Overview
Problem
Existing methods for creating fiber plies for composite parts with non-developable surfaces, such as flexible abutments, face challenges in controlling fiber orientation and quantity accurately and reproducibly, leading to inconsistent mechanical characteristics and difficulties in shaping preimpregnated fibers to match complex geometries.
Innovation Solution
A method involving the use of canvases to define an annular space, where fibers are placed and stitched between them, allowing for precise control of fiber orientation and quantity, and additional fibers are added to maintain constant concentration, enabling the creation of uniform fiber plies that can be easily shaped and molded into complex forms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If preimpregnated fabric plies are used for draping and molding, then mechanical strength is improved, but flexibility and ease of shaping to match complex geometries deteriorates
Solution Approach 1:
The invention applies preliminary action by pre-assembling the fiber reinforcement structure on a mandrel in the desired three-dimensional configuration before the molding process. The fibers are placed and stitched into the final spherical ring shape in advance, creating a preform that maintains flexibility during assembly but achieves structural integrity before resin injection. This resolves the contradiction by allowing easy shaping during the preliminary assembly phase while ensuring mechanical strength in the final molded product.
2Adaptability or versatility
If manual draping of fiber plies is performed directly on a shaping support, then adaptability to complex shapes is improved, but manufacturing precision and reproducibility deteriorates
Solution Approach 1:
The invention replaces the manual mechanical draping process with an automated fiber placement system. A robotic or automated mechanism places fibers precisely on a mandrel according to programmed trajectories, ensuring consistent fiber orientation and density. This substitution maintains adaptability to complex spherical ring shapes while dramatically improving manufacturing precision and reproducibility by eliminating manual variability.
Solution Approach 2:
The invention changes the working parameters by transitioning from direct manual draping on the final mold to automated fiber placement on a removable mandrel. This parameter change allows the use of a standardized mandrel geometry that can be easily replicated, ensuring consistent fiber placement parameters (density, orientation, coverage) across multiple production runs while maintaining the ability to create complex three-dimensional shapes.
3Manufacturing precision
If female mold element is put into place during molding, then complete molding is achieved, but ply slipping and wrinkle formation increase
Solution Approach 1:
The invention applies preliminary action by creating a complete three-dimensional fiber preform on the mandrel before the molding operation. The fiber reinforcement is fully assembled and stitched into its final configuration in advance, eliminating the need to handle and position multiple separate plies during molding. This preliminary assembly ensures ply stability while achieving molding completeness through subsequent resin injection.
Solution Approach 2:
The invention extracts the fiber placement operation from the molding process itself. Instead of performing fiber placement and molding as integrated steps requiring female mold elements, the fiber reinforcement is independently assembled on a mandrel as a separate preform preparation stage. This separation eliminates the interference between mold closure and fiber positioning, preventing ply slipping and wrinkling while maintaining molding completeness.
Data Source
AI summary
The invention provides a method of making a fiber ply for forming a preform of a composite part in the form of a body of revolution having a non-developable surface, the method being characterized in that it comprises the steps consisting in:defining an annular space (23) with first and second canvases (20, 21) respectively defining an inner periphery and an outer periphery thereof;placing fibers between the canvases (20, 21) by placing the fibers in the annular space in at least one direction and by holding said fibers on the canvases by stitching;implementing circular connection stitching in the vicinity of the inner periphery of the annular space (23); andcutting out the fiber ply as made in this way in the annular space (23) in order to extract it from the canvases.