Shock Strut Damping Curve Switching With Rotating Metering Pin
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Solution Overview
Problem
Existing shock strut systems in aircraft landing gear lack the ability to dynamically adjust damping curves to accommodate different aircraft operations such as conventional landing and catapult launch, leading to suboptimal performance and energy dissipation.
Innovation Solution
A multi-actor damping system that includes a damping actor selector, which uses a hydraulic or pneumatic actuation system to rotate a metering pin and main orifice plate to various positions, altering the damping curve by clocking the metering pin and/or main orifice plate to different actor angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single damping curve is used in the shock strut system, then the structure is simple and easy to manufacture, but the system cannot adapt to different aircraft operations such as conventional landing and catapult launch
Solution Approach 1:
The system dynamically switches between different damping curves by rotating the metering pin to different angular positions. The metering pin has varying cross-sectional areas at different angular positions, allowing the system to adapt damping characteristics for different operations such as conventional landing, catapult launch, and arrested landing.
Solution Approach 2:
A single shock strut system performs multiple damping functions by using a multi-profile metering pin that can be oriented at different angles. The same physical component provides different damping curves for various aircraft operations, eliminating the need for separate damping systems for each operation.
2Reliability
If a multi-actor damping system with selectable configurations is implemented, then damping performance is optimized for specific operations, but the device complexity increases
Solution Approach 1:
The system uses a rotatable metering pin that can be positioned at specific angular orientations corresponding to different damping curves. A damping curve selector mechanism allows the system to dynamically switch between pre-configured damping profiles, ensuring reliable performance for the specific operation being performed.
Solution Approach 2:
The system changes the damping parameter by rotating the metering pin to different angular positions. Each angular position presents a different cross-sectional area profile to the fluid flow, thereby changing the damping characteristics without altering the fundamental structure of the shock strut.
3Ease of operation
If the metering pin is rotated to different positions to alter damping curve, then damping optimization for specific operations is achieved, but the actuation mechanism complexity increases
Solution Approach 1:
The system uses pneumatic or hydraulic actuators to rotate the metering pin to the desired angular position. The actuator receives pressurized fluid through conduits and uses the fluid pressure to drive the rotation mechanism, providing easy and reliable damping curve selection without complex mechanical linkages.
Solution Approach 2:
The manual or mechanical rotation of the metering pin is replaced with an automated actuation system using pneumatic or hydraulic actuators. This substitution reduces the complexity of manual operation and provides more reliable, repeatable positioning of the metering pin at the required angular orientations.
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 system allows for the selection of pre-defined damping actor configurations based on specific aircraft activities, enhancing shock strut performance by optimizing damping profiles for various operations, such as landing, catapult launch, and taxiing.
Implementation Method 1
a trapped volume of gas is compressed as the shock strut is axially compressed, and a volume of oil is metered through an orifice. The gas acts as an energy storage device, similar to a spring
Implementation Method 2
Shock struts also dissipate energy by passing the oil through the orifice so that as the shock absorber is compressed or extended, its rate of motion is limited by the damping action from the interaction of the orifice and the oil
Data Source
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AI summary
A damping actor selector may be configured to transition a multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The multi-actor damping system may be used in a shock strut assembly to alter a damping curve of the shuck strut assembly. The damping actor selector (170) may be coupled to a metering pin (140) of a shock strut assembly. The damping actor selector may be configured to rotate the metering pin to transition the multi-actor damping system from a first damping actor configuration to a second damping actor configuration. The first damping actor configuration may correspond to a first damping curve. The second damping actor configuration may correspond to a second damping curve. The first damping curve being different than the second damping curve.