Method for manufacturing a composite preform for the manufacture of a composite panel with double curvature geometry
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Solution Overview
Problem
Biaxial non-woven fabrics, used in manufacturing composite materials for non-developable final shape parts, lack sufficient stiffness and mechanical strength due to limited fiber orientations, and tri-axial non-woven fabrics are prone to fiber breaks and corrugations when applied to complex shapes like revolution surfaces.
Innovation Solution
A method involving a tri-axial non-woven fabric with circumferential fibers and two other layers oriented in different directions, where the seams allow for sliding and unraveling of fibers to adapt to complex shapes, achieving quasi-isotropic mechanical properties and preventing fiber breaks by forming sheaths for circumferential fibers, which are tensioned and pressed to conform to the shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If biaxial non-woven fabric is used, then the fabric can be applied to non-developable shapes without fiber breaks, but the stiffness and mechanical strength are insufficient
Solution Approach 1:
The patent uses tri-axial non-woven fabric combining three different fiber orientations (0°, ±45°, or 90°) in a single layer, creating a composite structure that achieves both adequate mechanical strength and flexibility for non-developable shapes. This multi-directional fiber arrangement provides quasi-isotropic mechanical properties while maintaining the ability to drape over complex geometries without fiber breakage.
Solution Approach 2:
The invention transitions from two-dimensional biaxial fabric (two fiber directions) to three-dimensional tri-axial fabric (three fiber directions), adding an extra dimension of fiber orientation. This dimensional enhancement provides comprehensive mechanical reinforcement while preserving the fabric's adaptability to non-developable surfaces.
2Strength
If tri-axial non-woven fabric is used, then good stiffness and mechanical strength are achieved, but fiber corrugations occur on revolution surfaces
Solution Approach 1:
The patent employs different fiber orientation angles in different layers of the tri-axial fabric (e.g., 0°/±45°/90° or variations thereof), allowing each layer to contribute differently to the overall performance. This local differentiation optimizes stiffness where needed while maintaining drapeability in other areas, preventing corrugation on revolution surfaces.
Solution Approach 2:
The invention modifies the fiber orientation parameters by using specific angle combinations (0°, ±45°, or 90°) and adjusts the spacing and tension of seams to control fabric behavior during forming. These parameter optimizations enable the fabric to achieve good surface quality on revolution surfaces while maintaining adequate stiffness.
3Strength
If multiple thicknesses of biaxial fabric are applied, then good stiffness and mechanical strength are obtained, but the device complexity and manufacturing time increase
Solution Approach 1:
The patent merges multiple fabric layers with different fiber orientations into a single tri-axial non-woven fabric structure. Instead of applying multiple separate biaxial fabric layers, the invention combines the functionality of multiple orientations into one integrated tri-axial layer, reducing manufacturing steps and complexity while achieving equivalent or superior mechanical strength.
Data Source
AI summary
A method for manufacturing a preform for producing a part made of composite material with an unchangeable final shape includes supplying a triaxial non-woven textile comprising a layer of fibers orientated in a first direction, a layer of fibers orientated in a second direction, a layer of fibers orientated in a third direction, and seams extending parallel to each other and forming sheaths for the circumferential fibers, arranging the textile on an element of unchangeable shape by placing the seams parallel to the circumferential direction of the element, and sliding the circumferential fibers into the sheaths so that the textile is in continuous contact with the element.