Rivet Washer Assembly for CMC Brake Disk Wear Liner Protection
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Solution Overview
Problem
The existing riveting process for coupling carbon wear liners to ceramic matrix composite (CMC) cores in aircraft brake systems often causes damage to the wear liners and the reusable friction disk core during assembly and de-riveting.
Innovation Solution
The use of washers, specifically a first washer positioned at the distal end of the rivet and a second washer at the proximal end, to distribute the load of the rivet head and upset head, thereby reducing the risk of damage to the wear liners and the friction disk core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the rivet distal end is upset to form an upset head for coupling wear liners to the friction disk core, then the wear liners are securely attached to the core, but the concentrated load from the upset head causes damage to the wear liners and the friction disk core
Solution Approach 1:
A washer is introduced as an intermediary component between the upset head of the rivet and the wear liner/friction disk core. The washer distributes the concentrated load from the upset head over a larger surface area, preventing damage to the wear liner and friction disk core while maintaining secure attachment. The washer acts as a mediator that transfers the bonding force without concentrating stress at a single point.
2Reliability
If a rivet is used to couple wear liners to the friction disk core, then the wear liners are firmly bonded to the core, but the riveting process causes damage during both assembly and de-riveting operations
Solution Approach 1:
The washer serves as a protective intermediary during both the riveting assembly process and the subsequent de-riveting process. During assembly, it protects the wear liner from the upset head. During de-riveting, it protects the friction disk core from the rivet, enabling removal of the wear liner without damaging the reusable core.
Solution Approach 2:
The washer is installed beforehand to provide cushioning protection against the concentrated forces that will be applied during the upset process. This pre-positioned protective element prevents direct contact between the rivet upset head and the wear liner, cushioning the impact and distributing stresses before damage can occur.
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 implementation of washers in the riveting process effectively prevents or reduces damage to the wear liners and the friction disk core, enhancing the durability and longevity of these components.
Implementation Method 1
the upset head pushes against the washer thereby spreading a load of the upset head to at least one of the first wear liner or the second wear liner
Implementation Method 2
the flat washer is malleable and configured to form a frustoconical shape of a counterbore of an opening through which the rivet is positioned
Data Source
AI summary
A friction disk is provided. The friction disk includes a friction disk core, a first wear liner located over a first surface of the friction disk core, a second wear liner located over a second first surface of the friction disk core, a washer, and a rivet. The first wear liner and the second wear liner are coupled to the friction disk core via the rivet. The washer is configured to be positioned at a distal end of the rivet, such that, in response to the distal end of the rivet being upset forming an upset head, the upset head pushes against the washer thereby spreading a load of the upset head to at least one of the first wear liner or the second wear liner.