Needled Dry Preform Impregnation for Composite Parts
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Solution Overview
Problem
The production of composite material parts with unidirectional continuous fibers and a polymer matrix faces challenges such as high manufacturing costs and significant scrap rates due to insufficient permeability and cohesion in dry preforms, particularly during impregnation processes like RTM at high pressure and temperature.
Innovation Solution
A method involving the application of non-woven fibers or filaments to the dry preform and needling them with a device having notched needles to increase cohesion and permeability, allowing for efficient impregnation without delamination or dry areas, using a needling density and filament configuration that optimizes fiber retention and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dry preforms are produced by automatic draping of continuous unidirectional fibers, then manufacturing cost is reduced and waste rate is limited, but permeability and cohesion between fibers are insufficient for rapid impregnation
Solution Approach 1:
The invention combines two different fiber types (continuous unidirectional fibers and discontinuous staple fibers) to create a composite preform structure. The continuous fibers provide structural strength while the discontinuous fibers improve permeability and cohesion, enabling both cost-effective manufacturing and satisfactory impregnation properties
Solution Approach 2:
The invention applies discontinuous staple fibers specifically in the regions where improved permeability and cohesion are needed, while maintaining the continuous unidirectional fiber structure in areas requiring structural integrity. This localized enhancement allows the preform to meet both manufacturing and impregnation requirements
2Productivity
If high pressure and high temperature are used for RTM injection impregnation, then impregnation speed is improved, but preform deterioration and delamination occur due to insufficient cohesion
Solution Approach 1:
The invention performs preliminary needling treatment on the preform before impregnation to enhance fiber cohesion and inter-ply bonding. This pre-treatment ensures the preform can withstand the high pressure and temperature conditions during RTM injection without deteriorating or delaminating
Solution Approach 2:
By combining continuous unidirectional fibers with discontinuous staple fibers in a needled non-woven structure, the invention creates a composite preform with improved mechanical properties and cohesion, allowing high-pressure impregnation to proceed without preform damage
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
Facilitates rapid and satisfactory impregnation with high rates of polymer infiltration, reducing scrap rates and improving the mechanical resistance of the composite material parts, especially in high-pressure and high-temperature conditions.
Implementation Method 1
a step of needling said filaments by means of a needling device comprising a plurality of needles, each provided with at least one notch, such that filaments are driven by the needles and arranged in a direction substantially perpendicular to the continuous fibers of the dry preform
Implementation Method 2
a step of impregnating the dry preform with a first impregnation polymer, for example by injection and/or infusion, to form a part made of composite material
Implementation Method 3
the needles are driven in a reciprocating motion by a drive system of the needling device, to pass through the preform, preferably from one side to the other. During the movement of the needles towards the preform, at least a portion of these filaments are positioned in the notches of the needles
Data Source
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AI summary
The present invention concerns a method for producing a composite material part comprising - a step of producing an initial dry preform (101), formed from unidirectional continuous dry fibres, - a step of applying non-woven filaments to a first main face (111) of the dry preform, - a step of needle-punching said filaments by means of a needle-punching device (5) comprising a plurality of needles (51), each provided with at least one notch, such that filaments are drawn by the needles and arranged in a direction substantially perpendicular to the continuous fibres of the dry preform , and - a step of impregnating the dry preform with an impregnation polymer in order to form the matrix of the composite material part.