Ram Air Turbine Actuator Piston Damping for Windmilling Loads
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Solution Overview
Problem
Conventional ram air turbine (RAT) actuators experience high loads due to low resonance excited by in-flight vibratory loadings, particularly in the windmilling test frequency range, leading to significant cycles and potential damage.
Innovation Solution
The design incorporates damping holes and a lock rod hole in the RAT actuator piston to dissipate vibratory loads, allowing the piston to move and dissipate energy through fluid flow, while maintaining the stowed position and enabling fast deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the RAT actuator is designed with a rigid piston structure to maintain stowed position, then the stowed position stability is improved, but the actuator experiences very high loads due to low resonance excited by windmilling loadings
Solution Approach 1:
The patent incorporates damping holes in the piston structure beforehand to cushion against vibratory loads. These holes allow fluid to flow through the piston during windmilling, dissipating energy and reducing the impact of resonant vibrations before they can cause damage to the actuator components.
Solution Approach 2:
The damping holes act as an intermediary mechanism between the external vibratory loads and the rigid piston structure. By allowing controlled fluid flow through these holes, the system mediates the transmission of vibratory energy, converting it into fluid flow and heat rather than allowing it to directly stress the mechanical components.
2Force
If damping holes are added to the piston to dissipate vibratory energy, then the load reduction is achieved, but the device complexity increases
Solution Approach 1:
The patent applies the porous materials principle by incorporating damping holes directly into the piston structure. This creates a controlled porous pathway that allows fluid flow for damping purposes while maintaining the structural integrity of the piston. The holes are strategically positioned and sized to provide effective damping without requiring additional complex damping components.
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 solution effectively reduces loads on the RAT and actuator, enhancing robustness and reducing weight and cost by dissipating vibratory energy without increasing deployment time.
Implementation Method 1
The one or more damping holes are configured to allow flow through the damping holes in the locked position to allow the RAT actuator piston to move within the RAT actuator in the locked position to dissipate vibratory loads
Data Source
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AI summary
A ram air turbine (RAT) actuator piston (100) can include a body (101) defining a piston structure having an inner cavity (103). The piston (100) can include one or more damping holes (109) axially defined through the body to the inner cavity (103) and a lock rod hole (111) defined axially through the body to the inner cavity (103). The lock rod hole (111) can have a larger flow area than one or more of the one or more damping holes. The lock rod hole (111) can be configured to receive a lock rod (213) of a RAT actuator (200) to at least partially block flow through the lock rod hole (111) when the lock rod (213) is in a locked position. The one or more damping holes (109) can be configured to allow flow through the damping holes (109) in the locked position to allow the RAT actuator piston (100) to move within the RAT actuator (200) in the locked position to dissipate vibratory loads.