Woven Composite Preform Water-Jet Expansion for Intra-Yarn Densification
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Solution Overview
Problem
Existing methods face challenges in achieving uniform densification of the core of continuous yarns in woven fiber fabrics, leading to inadequate mechanical properties and fatigue strength at high temperatures due to difficulty in accessing and filling intra-yarn pores, especially when using liquid or gaseous techniques.
Innovation Solution
A method involving the treatment of woven fiber fabrics with pressurized water jets to expand the yarns, increasing intra-yarn porosity and allowing for improved matrix infiltration, with pressures up to 100 bars and nozzle distances of at least 50 mm to maintain yarn continuity and facilitate densification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If liquid or gaseous techniques are used to densify the preform, then the matrix can be deposited in the preform, but the intra-yarn pores are too small and difficult to access for adequate densification
Solution Approach 1:
The fabric is subjected to water jet treatment before densification to pre-expand the yarns and create larger intra-yarn pores. This preliminary action modifies the fabric structure in advance, making the pores more accessible to the matrix during subsequent densification, thereby resolving the accessibility issue without compromising densification uniformity
Solution Approach 2:
The physical state and dimensions of the yarns are changed by applying water jets that temporarily swell the yarns and increase pore size. This parameter change in yarn dimensions and porosity allows better penetration of liquid or gaseous matrix precursors into the intra-yarn regions, improving both accessibility and densification quality
2Manufacturing precision
If high pressure water jets are used to expand yarns, then intra-yarn porosity increases for better matrix infiltration, but the fiber fabric may be damaged
Solution Approach 1:
The water jet pressure is optimized to a specific range (50-200 bar) that is sufficient to expand yarns and increase intra-yarn porosity but remains below the threshold that would damage the fiber fabric. This precise parameter control allows achieving the desired porosity improvement while maintaining fabric integrity and reliability
Solution Approach 2:
Instead of using mechanical means that might directly contact and potentially damage fibers, water jets are used as a fluid medium to transmit the expanding force. The water acts as an intermediary that distributes pressure uniformly, expanding yarns through hydrostatic pressure without localized mechanical stress that could compromise fiber integrity
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 enhances the mechanical properties and lifetime of the composite material by ensuring adequate matrix infiltration within the yarns, resulting in improved thermomechanical performance without damaging the fiber fabric.
Implementation Method 1
subjecting said fabric to one or more jets of water under pressure so as to reduce the mean fiber percentage in the fabric
Implementation Method 2
a step of treating the fabric by subjecting said fabric to one or more jets of water under pressure
Data Source
AI summary
A method of fabricating a composite material part comprises fiber reinforcement densified by a matrix. The method comprises the following steps: making a fiber fabric by weaving yarns having an initial mean fiber percentage; and densifying the fiber fabric with a matrix. The fiber fabric is subjected, prior to densification, to one or more jets of water under pressure so as to reduce the mean fiber percentage in the fabric to a value lying in the range 20% to 45%.