Fiber Preform with Segmented Zones for High Volume Fraction
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Solution Overview
Problem
Current methods for producing fiber composite components are complex, expensive, and inefficient in achieving high fiber volume fractions and adapting to local loads, often resulting in suboptimal mechanical properties and significant material waste.
Innovation Solution
A fiber preform with a structure comprising reinforcing fiber bundles oriented in different spatial directions and unidirectionally aligned fiber strands, allowing for high fiber volume fractions and flexible adaptation to local stresses, achieved through a combination of resin compositions and precise placement of fiber bundles and slivers within a mold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If random isotropic arrangement of reinforcing fibers is used, then stability of preform is achieved, but fiber volume fraction is limited to maximum 30% and only a fraction of fibers are in the direction of stress
Solution Approach 1:
The preform is segmented into two distinct zones: a first zone with random isotropic arrangement of short fiber bundles providing stability, and a second zone with unidirectionally aligned fiber strands providing high strength. This segmentation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the preform are assigned different fiber arrangements and properties: the first zone has random isotropic arrangement for stability, while the second zone has unidirectional alignment for maximum strength. This local differentiation optimizes both stability and fiber volume fraction in their respective locations.
2Manufacturing precision
If TFP process with CNC-controlled sewing is used, then fiber alignment appropriate to load is achieved, but production is very time-consuming and expensive
Solution Approach 1:
The invention uses disposable unidirectional yarns that are placed and then cut to length, replacing the expensive and time-consuming CNC-controlled sewing process. The yarns serve their alignment function and are then discarded, achieving high precision fiber placement at lower cost and faster speed.
Solution Approach 2:
The mechanical sewing system (needles, threads, CNC control) is replaced with a simpler placement and cutting system. The alignment function is achieved through the inherent directionality of the yarns rather than mechanical stitching, significantly reducing production time and cost.
3Adaptability or versatility
If multiaxial fabrics are used, then fiber alignment in multiple directions is achieved, but material waste increases and impact strength is reduced due to sewing threads
Solution Approach 1:
The harmful sewing threads from multiaxial fabrics are extracted and replaced with a binder material system. The binder material holds the fiber bundles in place without introducing foreign elements that would reduce impact strength or create waste issues.
Solution Approach 2:
The invention creates a composite structure combining short fiber bundles in random arrangement with unidirectional fiber strands, bound together by binder material. This composite approach achieves multi-directional reinforcement without the drawbacks of traditional multiaxial fabrics.
4Stability of the object's composition
If pre-impregnation with small amounts of curable plastic material is used, then fixation of reinforcing fibers is improved, but fiber volume fraction remains limited
Solution Approach 1:
The invention changes the binder material parameters by using thermoplastic materials with melting points suitable for the processing temperature range. This allows the binder to be applied in a molten state that penetrates and binds fibers effectively, then solidifies to provide fixation without limiting fiber volume fraction.
Solution Approach 2:
The binder material is applied locally at the interfaces between fiber bundles and strands, rather than as a comprehensive pre-impregnation. This localized binding approach provides sufficient fixation while maximizing the volume fraction of reinforcing fibers.
Data Source
AI summary
The invention relates to a fibre preform (1) for producing fibre composite structures, the wall of said preform comprising at least one first zone (4) that consists of reinforcing fibre bundles (5) with a first resin composition, and at least one second zone (7) consisting of at least one sliver, consisting of at least one uni-directionally aligned reinforcing yarn strand (8) with a second resin composition, said reinforcing fibre bundles (5) being oriented, in the at least one first zone (4) and in an observation direction, parallel to the thickness extension in different spatial directions from one another, and the at least one second zone forming, in an observation direction, a discrete region that is perpendicular to the thickness extension of the wall. In addition, the invention relates to a composite material component that consists of such a fibre preform.