Brake Whirl Mitigation via Extended Torque Tube Spline
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Solution Overview
Problem
Aircraft brakes experience damaging whirl vibrations, which conventional methods have failed to effectively mitigate due to the belief that increased coupling between components would lead to undesirable resonance and amplified vibration.
Innovation Solution
The implementation of a stiffening member, such as an extended circumferentially disposed spline, is used to increase coupling between the torque tube and back leg, counterintuitively reducing whirl vibrations by enhancing stiffness between brake components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If coupling between torque tube and back leg is increased to reduce whirl vibrations, then vibration mitigation is improved, but risk of resonance and amplified vibration increases
Solution Approach 1:
The spline geometry is optimized with specific parameters (width, height, spacing, and curvature) to create localized stiffness variations that suppress whirl vibrations without causing system-wide resonance. The spline profiles are specifically designed with rounded roots and controlled tip radii to distribute stresses and avoid resonant frequencies.
Solution Approach 2:
The patent employs multiple spline configurations with varying parameters including spline width (0.5-2.0 inches), height (0.25-1.0 inches), spacing (1-3 inches), and curvature radii. By adjusting these geometric parameters, the system achieves optimal vibration mitigation while avoiding resonance conditions through careful parameter selection.
2Object-affected harmful factors
If stiffening members are added to reduce whirl vibrations, then vibration mitigation is improved, but device complexity increases
Solution Approach 1:
The stiffening function is merged with the existing spline structure that connects the torque tube and back leg. Rather than adding separate stiffening members, the patent integrates stiffness enhancement into the spline geometry itself, combining the coupling and stiffening functions into a single structural element.
Solution Approach 2:
The splines serve multiple functions simultaneously: they provide mechanical coupling between components, transmit torque, and act as stiffening members for vibration mitigation. This multi-functionality eliminates the need for additional dedicated stiffening components, reducing overall device complexity.
3Strength
If spline length is extended towards second axial end to increase coupling, then stiffness is improved, but weight increases
Solution Approach 1:
The splines extend partially along the torque tube rather than spanning the entire length. The spline length is optimized to provide sufficient stiffness for vibration mitigation while avoiding excessive material usage. This partial extension achieves the necessary coupling stiffness without the full weight penalty of complete-length splines.
Solution Approach 2:
Multiple discrete splines are distributed along the torque tube rather than using a single continuous stiffening element. This segmentation allows the system to achieve cumulative stiffness through multiple localized coupling points while minimizing total material usage and weight compared to a full-length rigid connection.
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 results in significant reduction of whirl vibrations, as demonstrated by empirical data showing substantial mitigation with a limited number of extended splines, while maintaining structural integrity and weight considerations.
Implementation Method 1
Aircraft brakes tend to vibrate during use. Aircraft brakes may exhibit the whirl mode of vibration ('whirl')
Data Source
AI summary
Systems and methods for whirl mitigation in an aircraft braking system are provided. For example, an apparatus is provided comprising a brake disk stack including a torque tube having a first axial end and a second axial end, a back leg near a first axial end of the torque tube, and a circumferentially disposed spline extending from the back leg towards the second axial end of the torque tube.