Unidirectional Fabric Permeability via Core-Sheath Transverse Threads
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Solution Overview
Problem
Existing unidirectional fabrics for producing composite material components lack sufficient stability and drapability, leading to poor handling and permeability issues during matrix infiltration, which affects the strength and impact resistance of the final components.
Innovation Solution
A method involving the interweaving of transverse threads with a core-sheath structure into a flat layer of multifilament reinforcement yarns to create adjustable permeability and high stability, using a thermoplastic polymer material for bonding and stabilization, allowing for targeted adjustment of permeability between 10 to 600 l/dm²/min without compromising strength or drapability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If unidirectional fabrics are used for producing composite material components, then high strength in stress directions can be achieved, but insufficient stability and drapability result in poor handling
Solution Approach 1:
A thermoplastic binder is introduced as an intermediary substance between the reinforcing fibers. This binder is applied in the form of dots, lines, or areas, and when heated above its melting temperature, it acts as a mediator that bonds the fibers together, providing stability and improving drapability without compromising the high strength characteristics of the unidirectional fabric structure.
2Strength
If unidirectional fabrics are used for producing composite material components, then high strength in stress directions can be achieved, but insufficient stability and drapability result in poor drapability
Solution Approach 1:
The thermoplastic binder serves as a mediator that, when melted, allows the fabric to be draped and conform to molds. Upon cooling, it solidifies and locks the draped shape in place, thereby improving drapability while preserving the underlying fiber architecture that provides high strength in stress directions.
3Ease of manufacture
If existing unidirectional fabrics are used, then production of composite components is enabled, but permeability issues during matrix infiltration affect the strength and impact resistance
Solution Approach 1:
The permeability of the unidirectional fabric is optimized by controlling the distribution and amount of thermoplastic binder applied. By adjusting these parameters, the fabric achieves appropriate porosity that facilitates uniform matrix infiltration while maintaining structural integrity, thereby ensuring reliable strength and impact resistance in the final composite component.
4Stability of the object's composition
If thermoplastic polymer material is used for bonding, then dimensional stability and adjustable permeability are achieved, but additional processing steps are required
Solution Approach 1:
The thermoplastic binder exploits phase transitions (melting and solidification) to provide bonding functionality. The binder is applied in a solid state, melted during a heating step to enable fiber bonding and adjust permeability, then solidifies upon cooling to lock in dimensional stability. This phase transition mechanism achieves the desired properties through a relatively simple thermal processing cycle.
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
The method produces unidirectional fabrics with enhanced dimensional stability, adjustable permeability, and improved strength and impact resistance, enabling efficient matrix infiltration and reduced risk of defects in composite components.
Implementation Method 1
the adjacent multifilament reinforcement yarns being joined together by hot melt bonding via the first component of the transverse threads
Implementation Method 2
lanes are formed through which a permeability of 10 to 600 l/dm2/min, measured according to EN ISO 9237, is adjustable
Data Source
Figure 1~2A
Figure 1A~2B
AI summary
The invention relates to a method for producing a textile unidirectional fabric, wherein at least one planar layer of multi-filament reinforcement threads arranged parallel to each other are woven with each other over transverse threads, wherein transverse threads having a core-sheath structure and a titer of 10 to 40 tex are used as transverse threads, wherein the transverse threads have a first component, which structures the sheath, and a second component, which structures the core, wherein the first component has a lower melting temperature than the second component, the first component is a meltable thermoplastic polymer material and, via the first component of the transverse threads, the adjacently arranged multi-filament reinforcement threads are connected to each other by hot melting, wherein alleys are formed in the unidirectional fabric by interweaving the multi-filament reinforcement threads together with the transverse threads, by means of which a permeability of 10 to 600 l/dm2/min can be established. A preferred embodiment relates to a method for producing a unidirectional fabric having a fleece. The invention further relates to a fiber preform, produced from the unidirectional fabric.