Engine-Mast Assembly Damping Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing engine assembly with an aircraft mast experiences mechanical fatigue due to vibrations from the turbine engine, leading to costly frequent inspections and replacements of components.
Innovation Solution
The assembly incorporates a connecting device with a pivotable spreader bar and elastic stops that limit rotational movement, reducing oscillations and fatigue by using spring-like metal stops to absorb and distribute stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the spreader bar is allowed to pivot freely around the axis of rotation, then the connecting device can accommodate engine movements and vibrations, but the oscillating movement amplified by vibration frequencies creates mechanical fatigue of the spreader bar and connections
Solution Approach 1:
The invention introduces a dynamic damping mechanism that allows the spreader bar to pivot freely during normal operation to accommodate engine movements, while automatically providing damping resistance when oscillation frequencies match the natural frequency. The damper transitions between free-motion and constrained-motion states based on vibration conditions, resolving the contradiction between adaptability and fatigue resistance.
Solution Approach 2:
The damping mechanism changes the effective rotational stiffness parameter of the spreader bar based on vibration conditions. During normal operation, the bar experiences minimal resistance allowing full adaptability. When resonance occurs, the damper increases rotational resistance to suppress oscillations and prevent fatigue, thus dynamically adjusting the mechanical parameter to resolve the contradiction.
2Strength
If rigid connections are used between the spreader bar and the shoe/main yoke, then structural strength is improved, but mechanical fatigue from amplified vibrations increases
Solution Approach 1:
The invention introduces a damping mechanism as an intermediary element between the spreader bar and the rigid structure (shoe/main yoke). This intermediary absorbs and dissipates vibrational energy, preventing the transmission of amplified oscillations to the rigid connections. The rigid structure maintains its strength while the damper protects against fatigue by decoupling the vibration transmission path.
3Reliability
If the damping mechanism uses high rotational inertia, then oscillations are better suppressed, but the response time of the connecting device to engine movements increases
Solution Approach 1:
The damping mechanism is designed with dynamic characteristics that provide high rotational inertia only when oscillation occurs at resonant frequencies. During normal engine movements and transient conditions, the mechanism maintains low resistance allowing rapid response. This frequency-selective damping resolves the contradiction by being aggressive only when needed for oscillation suppression while remaining compliant during normal operation.
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 design reduces mechanical fatigue and the need for frequent inspections, lowering operational costs by minimizing the impact of engine vibrations on the connecting components.
Implementation Method 1
elastic stops that limit rotational movement, reducing oscillations and fatigue by using spring-like metal stops to absorb and distribute stress
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an assembly of an engine (5) with a mast (6), comprising a force-retaining assembly (9) having a connecting device (120) fixed to the mast and two connecting rods (10, 11), the connecting device (120) comprising: - a shoe (121) fixed to the mast; - a rocker arm (122), extending between first and second ends (122a, b), and having a central part (122c) connected to the shoe by a main connection (130) comprising a main axis of rotation (133, Rp) contained in a plane of symmetry (V) of the connecting device (120); - two fittings fixed (160, 170) to the shoe, on either side of the plane of symmetry, each fitting having two arms between which the rocker arm is positioned;a first, respectively second, connecting rod comprising a front end fixed to the engine and a rear end fixed to the first, respectively second, end of the rocker arm as well as to the first, respectively second fitting (160,170) by a secondary connection, the rocker arm (122) comprising two extensions (122p), with an extension arranged at each end, each extension being associated with a pair of elastic stops (185) sandwiching the extension, and where for the first, respectively second end of the rocker arm, each stop is positioned between a branch of the first, respectively second fitting and the extension.;