Shock Strut Pressure Relief Valve for Hard-Landing Damping
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Solution Overview
Problem
Aircraft shock struts face structural damage during hard-landing events due to pressure spikes exceeding design thresholds, leading to ineffective energy absorption and potential damage.
Innovation Solution
A shock strut assembly with a pressure relief valve system that allows fluid flow from a lower chamber to an upper chamber during pressure spikes, providing additional damping and preventing fluid flow back, thereby reducing pressure and mitigating damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional shock strut with sealed fluid chamber is used, then the shock strut can effectively absorb energy during normal landing events, but it cannot handle hard-landing events that cause pressure spikes exceeding design thresholds
Solution Approach 1:
A pressure relief valve is introduced as an intermediary component between the liquid chamber and mixed fluid chamber. This valve acts as a mediator that opens during hard-landing events to relieve excessive pressure from the liquid chamber to the mixed fluid chamber, preventing structural damage while maintaining normal operation during standard landing events
Solution Approach 2:
The system changes the flow parameters of the fluid based on pressure conditions. During normal operation, the pressure relief valve remains closed maintaining standard damping characteristics. During hard-landing events when pressure exceeds the threshold, the valve opens to increase fluid flow and reduce pressure, thereby changing the system's energy absorption parameters dynamically
2Object-affected harmful factors
If the pressure relief valve allows fluid flow during pressure spikes, then pressure is reduced and damage is prevented, but the valve must be configured to prevent fluid flow back under normal conditions
Solution Approach 1:
The pressure relief valve is designed with dynamic characteristics, transitioning between closed and open states based on real-time pressure conditions. The valve remains closed during normal operation to maintain system integrity and opens dynamically when pressure exceeds the threshold, then closes automatically when pressure normalizes, providing adaptive pressure management without requiring complex external control mechanisms
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 pressure relief valve system effectively reduces pressure spikes during hard landings, enhancing energy absorption and preventing structural damage to the aircraft and landing gear.
Implementation Method 1
the pressure relief valve is configured to allow the flow of the fluid in response to a pressure in the shock strut assembly being above a threshold
Implementation Method 2
a volume of oil is metered through an orifice... the rate of motion is limited by the damping action from the interaction of the orifice and the oil
Implementation Method 3
The gas acts as an energy storage device, such as a spring, so that upon termination of a compressing force the shock strut returns to its original length
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
A shock strut assembly is disclosed herein. The shock strut assembly includes a mixed fluid chamber (214), a liquid chamber (212) coupled to the mixed fluid chamber (214), a metering pin (222) having a first end and a second end and a channel (258) formed therein extending from the first end to the second end, the first end disposed in the liquid chamber (212) and the second disposed in the mixed fluid chamber (214), and a pressure relief valve (252) fluidly coupled to the liquid chamber (212) and the channel (258) in the metering pin (222), the pressure relief valve (252) configured to allow a flow of a fluid from the liquid chamber (212) to the channel (258) in the metering pin (222).