Aircraft Thrust Reverser Actuator Buckling Control
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Solution Overview
Problem
Movable thrust reverser cascade vanes in aircraft propulsion units face challenges with actuator buckling, particularly under fatigue conditions, which can lead to blocking or failure of the actuators.
Innovation Solution
The implementation of an inter-cascade structure that includes a channel with a cylindrical internal surface and an external ring on the actuator, both following specific directrix curves, to limit buckling by providing a controlled stop mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If movable cascade vanes are implemented in the thrust reverser, then the nacelle length and mass are reduced, but the actuators are subjected to increased buckling risk under fatigue conditions
Solution Approach 1:
The invention introduces an intermediary structure (the inter-cascade structure with channel and cylindrical internal surface) that acts as a mediator between the actuator and the external environment. This structure provides a controlled stop mechanism that limits buckling amplitude without interfering with the normal movement function of the actuator, thus resolving the contradiction between maintaining actuator mobility and preventing buckling failure.
Solution Approach 2:
The invention applies preliminary anti-action by pre-configuring the inter-cascade structure with a channel and cylindrical internal surface that will limit buckling before it can cause failure. The external ring on the actuator is designed to engage with this structure in advance, creating a controlled stop that prevents excessive buckling deformation from developing during fatigue conditions.
2Ease of operation
If the actuator is designed with greater freedom of movement, then the reverser operation is improved, but the actuator becomes more susceptible to buckling and deformation
Solution Approach 1:
The invention applies dynamics by creating a system that is flexible during normal operation but becomes constrained when needed. The actuator maintains full freedom of movement during normal reverser operation, but the inter-cascade structure with its channel and cylindrical surface provides dynamic constraint only when buckling occurs, allowing the system to adapt its stiffness based on operational conditions.
Solution Approach 2:
The invention changes the physical parameters of the actuator system by adding the external ring with specific geometric parameters (cylindrical external surface following a second closed directrix curve) that interacts with the channel's cylindrical internal surface. This parameter change enables the actuator to maintain mobility under normal conditions while providing geometric constraint against excessive buckling deformation.
Data Source
AI summary
A thrust reverser for an aircraft propulsion unit, including a movable system with cascade vanes and an actuator allowing moving a movable system between an advanced direct thrust position and a backward thrust reversal position, the system also including an inter-cascade structure for limiting buckling of the actuator, forming a channel crossed by the actuator and delimited by a cylindrical internal surface extending along a first closed directrix curve, the fixed portion of the actuator including an end equipped with an external ring for limiting buckling of the actuator, the ring having a cylindrical external surface extending along a second closed directrix curve, the first and second closed directrix curves preferably having the same shapes and being concentric while being spaced apart from one another with the same spacing.