Aircraft Engine Isolation Subframe Vibration Control
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Solution Overview
Problem
Aircraft engine installations face challenges in effectively isolating vibrations, particularly lower frequency vibrations, which can lead to noise and customer dissatisfaction. Additionally, traditional engine mount systems struggle with shock loading and vibration loading during engine failure, and they compromise forward thrust efficiency due to fixed thrust vectoring features.
Innovation Solution
The proposed engine isolation subframe incorporates a forward beam connected to two engines and an aft frame with elastomeric mounts, including forward and aft isolator assemblies. These assemblies are designed to mitigate vibrations transmitted from the engines, reducing noise and improving thrust efficiency by allowing for the removal of fixed thrust vectoring features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional engine mount systems are used with fixed thrust vectoring features, then engine support and thrust control are provided, but forward thrust efficiency is compromised and vibration isolation is insufficient
Solution Approach 1:
The engine mounting system is divided into separate functional components: vibration isolator assemblies are distinct from the engine support structure, with forward isolators connecting the forward beam to the forward frame and aft isolators connecting aft beams to the aft frame. This segmentation allows independent optimization of vibration isolation and thrust efficiency functions.
Solution Approach 2:
Vibration isolator assemblies serve as intermediary elements between the engine mounts and the aircraft airframe. These isolators mediate the connection, providing both structural support and vibration isolation without compromising forward thrust efficiency, as they allow the removal of fixed thrust vectoring features.
2Object-affected harmful factors
If traditional engine mounting systems are used, then engine support is provided, but lower frequency vibrations are not effectively isolated leading to noise
Solution Approach 1:
The vibration isolator assemblies are designed with specific elastomeric materials and geometric configurations that change the dynamic parameters of the mounting system. The isolators have optimized stiffness and damping characteristics that specifically target lower frequency vibrations, converting rigid mechanical connections into compliant, frequency-selective isolators.
Solution Approach 2:
The isolator assemblies utilize elastomeric materials that combine rubber-like flexibility with damping properties. These composite material structures provide both mechanical support and vibration isolation across different frequency ranges, with the elastomeric composition specifically tuned for lower frequency vibration attenuation.
3Strength
If rigid engine mounting structures are used for shock loading support, then structural strength is provided, but vibration transmission to the aircraft increases
Solution Approach 1:
The mounting system transitions from rigid, static connections to dynamic, compliant connections through the vibration isolator assemblies. The elastomeric isolators provide non-linear stiffness characteristics that maintain structural strength during shock events while dynamically isolating vibrations during normal operation, adapting their mechanical properties based on load conditions.
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 engine isolation subframe effectively reduces vibrations transmitted to the aircraft, leading to decreased cabin noise and increased forward thrust efficiency. This results in potential weight reduction, fuel savings, and increased payload capacity.
Implementation Method 1
at least one forward isolator assembly connected to the forward frame; and at least one aft isolator assembly connected to the aft frame
Implementation Method 2
These assemblies are designed to mitigate vibrations transmitted from the engines, reducing noise
Data Source
AI summary
An engine vibration isolation subframe for aircraft includes a forward frame and a forward beam connected to the forward frame. The forward beam includes a first end configured to connect to a first engine and a second end configured to connect to a second engine. An aft frame is disposed aft of the forward frame and includes a first aft beam connected to the aft frame and the first engine and a second aft beam connected to the aft frame and the second engine, where the second aft beam is disposed substantially opposite the first aft beam. At least one forward isolator assembly is connected to the forward frame and at least one aft isolator assembly is connected to the aft frame.