Needled Carbon-Carbon Brake Disks with Localized Profiles
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Solution Overview
Problem
Conventional carbon/carbon (C/C) brake disks manufactured from uniformly needled oxidized polyacrylonitrile (PAN) fibers lack optimal performance characteristics such as mechanical strength, heat conduction, and friction and wear properties due to uniform needling profiles.
Innovation Solution
The use of non-uniform needling profiles in carbon fiber preforms, where different needling densities and profiles are applied to various portions of the preform and brake disk, such as the outer, inner, and medial diameter portions, as well as heat affected zones, to optimize specific performance characteristics like friction, wear, mechanical strength, and densification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform needling profile is applied across the entire preform, then manufacturing simplicity is maintained, but performance characteristics such as mechanical strength, heat conduction, and friction properties are not optimized
Solution Approach 1:
The patent applies different needling profiles to different radial zones of the preform: a first needling profile (higher needle penetration density) is applied to outer and inner diameter portions to enhance mechanical strength and wear resistance, while a second needling profile (lower needle penetration density) is applied to the medial diameter portion to maintain heat conduction properties. This local differentiation optimizes performance characteristics across different functional zones of the brake disk.
2Strength
If higher needling density is applied to improve mechanical strength, then densification and strength increase, but heat conduction and friction properties deteriorate
Solution Approach 1:
The patent differentiates needling density by radial position: outer and inner diameter portions receive higher needling density to maximize mechanical strength where structural support is critical, while the medial diameter portion receives lower needling density to preserve heat conduction pathways where thermal management is paramount. This spatial differentiation resolves the contradiction between strength enhancement and heat conduction preservation.
3Reliability
If higher needling density is applied to improve wear resistance, then friction and wear characteristics improve, but mechanical strength and heat conduction are compromised
Solution Approach 1:
The patent applies elevated needling density specifically to outer and inner diameter portions where wear resistance is most critical due to higher contact stresses, while maintaining lower needling density in the medial diameter portion to preserve mechanical strength and heat conduction. This targeted approach optimizes wear characteristics without compromising overall structural integrity.
Data Source
AI summary
The present disclosure provides a fibrous preform, comprising an annulus having at least one of an outer diameter portion or an inner diameter portion, the outer diameter portion extending radially inward from an outer diameter of the fibrous preform and the inner diameter portion extending radially outward from an inner diameter of the fibrous preform. In various embodiments, the fibrous preform further comprises a medial diameter portion disposed between the outer diameter and the inner diameter, wherein the medial diameter portion comprises a first needling profile, and the at least one of the outer diameter portion or the inner diameter portion comprises a second needling profile. In various embodiments, the first needling profile is less than the second needling profile.