Carbon Fiber Preform Layering for Uniform Through-Thickness Orientation
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Solution Overview
Problem
Current methods for producing carbon fibre preforms for brake discs, such as impregnation/moulding and needle-felting, result in poor fibre distribution along the axis of rotation, leading to inadequate compressive strength, stiffness, shear strength, and thermal conductivity, with no existing method achieving a homogeneous fibre distribution across the entire height of the preform.
Innovation Solution
A method involving multiple layers of carbon fibres or carbon precursors, where each layer is needle-felted in a specific direction to ensure parallel fibre orientation, with non-woven and woven sub-layers combined to maintain even fibre density and distribution, allowing for controlled fibre arrangement both within and orthogonal to the main plane.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If impregnation/moulding methods are used to produce carbon fibre preforms, then production cost is reduced and ease of manufacture is improved, but fibre distribution along the axis of rotation becomes poor, resulting in inadequate compressive strength, stiffness, and thermal conductivity
Solution Approach 1:
The preform is divided into multiple layers (first layer, second layer, intermediate layers) with different fibre orientations. The first and second layers have fibres arranged substantially parallel to the axis of rotation, while intermediate layers have fibres arranged substantially perpendicular to the axis of rotation. This segmentation allows each layer to contribute differently to the overall mechanical properties, achieving homogeneous fibre distribution and improved compressive strength while maintaining ease of production through a systematic layering approach.
2Manufacturing precision
If needle-felting methods are used to improve fibre distribution along the axis of rotation, then compressive strength and stiffness are enhanced, but the fibre distribution becomes non-homogeneous across the entire height of the preform, particularly in the last superimposed layers
Solution Approach 1:
Different regions of the preform are given different fibre orientations to optimize local properties. The first and second layers (outer layers) have fibres arranged substantially parallel to the axis of rotation to provide compressive strength, while the intermediate layers have fibres arranged substantially perpendicular to the axis of rotation. This local quality variation ensures that each region contributes optimally to the overall mechanical properties, achieving homogeneous fibre distribution and improved compressive strength throughout the entire preform height.
3Volume of moving object
If multiple superimposed layers are created to increase preform height, then the overall structural integrity is improved, but the density of fibres arranged along the axis of rotation decreases significantly in the last superimposed layers
Solution Approach 1:
The multi-layer preform is segmented into specific layers with different fibre orientations. The first layer (bottom layer) and second layer (top layer) both have fibres arranged substantially parallel to the axis of rotation, ensuring high fibre density and compressive strength at the extremes. The intermediate layers have fibres arranged substantially perpendicular to the axis of rotation. This segmentation ensures that fibre density is maintained at acceptable levels throughout the entire height of the preform, with the outer layers providing the necessary structural 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 method achieves a substantially homogeneous fibre distribution across all layers, enhancing mechanical properties like compressive strength, stiffness, and thermal conductivity, while maintaining ease of production and cost-effectiveness.
Implementation Method 1
a step c) of needle-felting, by at least one needle-felting device, said first and said second superimposed layers in a needle-felting direction substantially parallel to said superimposition axis to arrange at least part of the fibres parallel to the superimposition axis
Data Source
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AI summary
A method is described for making a fibrous preform (1) of pre-set height (N) of carbon and/or fibres of a carbon precursor comprising a number (n) of layers (3',3",....,3n) of carbon fibres and/or fibres of a carbon precursor and the respective preform formed. The method comprises: - a step a) of providing at least one first layer (3') of carbon fibres and/or fibres of a carbon precursor; - a step b) of superimposing at least one second layer (3") of carbon fibres and/or fibres of a carbon precursor according to a pre-set superimposition axis (Z); - a step c) of needle-felting, by at least one needle-felting device (10), said first (3') and said second (3") superimposed layers in a needle-felting direction substantially parallel to said superimposition axis (Z) to arrange at least part of the fibres parallel to the superimposition axis (Z), said needle-felting device (10) having a plurality of needles equipped with a penetration dimension (p); - a step d) of repeating steps a-c until a needle-punched multilayer pre-body (2N) of pre-set height N is formed; - a step e) of superimposing a further layer of carbon fibres (3n+1) and/or fibres of a carbon precursor according to said pre-set superimposition axis (Z); - a step f) of needle-felting, by at least said needle-felting device (10), said further layer (3n+1) of carbon and/or fibres of a carbon precursor superimposed together with the underlying layers along a needle-felting direction substantially parallel to said superimposition axis (Z) to arrange at least part of the fibres parallel to the superimposition axis (Z), - a step g) of repeating steps e, f until forming a needle-punched multilayer pre-body (2N+p) of at least N+p height, - a step h) of cutting said needle-punched multilayer pre-body (2N+p) of at least N+p height, at height N, making two multilayer bodies, a first (2') and a second (2") multilayer body, respectively; said first multilayer body having height N.