Tuned Thrust Link Assembly for Aircraft Engine Noise Isolation
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Solution Overview
Problem
Noise transmission from an engine to an aircraft cabin through thrust links creates undesirable noise, particularly due to dynamic loads from rotating imbalances of engine blades, which existing technologies have not effectively addressed.
Innovation Solution
A thrust link assembly with a load transferring member and a tuned absorber, where the tuned absorber is coupled to the load transferring member to absorb specific noise frequencies, utilizing a damping member and viscoelastic layers or viscous fluids to reduce noise transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a thrust link is used to structurally connect an engine to an aircraft for transferring engine thrust loads, then engine thrust loads are effectively transferred to the aircraft, but dynamic loads from rotating imbalance of engine blades are transmitted as noise to the aircraft cabin
Solution Approach 1:
A tuned absorber is introduced as an intermediary component between the engine and the aircraft structure. The absorber couples to the thrust link and selectively absorbs dynamic loads at specific frequencies (such as engine order frequencies) before they can be transmitted to the aircraft cabin, thereby reducing noise while maintaining thrust load transfer capability
Solution Approach 2:
The thrust link system is modified by adding a tuned absorber with specific mass, stiffness, and damping parameters. The absorber is tuned to specific frequencies (e.g., engine order frequencies) by adjusting these parameters, allowing it to resonate at those frequencies and absorb the corresponding dynamic loads, thus changing the frequency response characteristics of the overall system
2Productivity
If the thrust link provides a dominant path for transferring dynamic loads from the engine to the fuselage, then engine thrust is effectively transmitted, but undesirable noise is generated in the aircraft cabin
Solution Approach 1:
The tuned absorber converts the harmful dynamic loads into beneficial resonant motion. By tuning the absorber to specific engine order frequencies, it resonates in response to those frequencies, absorbing the energy that would otherwise be transmitted to the cabin. The absorber effectively transforms the problem of dynamic load transmission into a controlled resonant response that protects the cabin from noise
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
Effectively reduces noise transmission by tuning the absorber to specific frequencies, such as those generated by engine shafts, improving cabin comfort by dampening tonal noise within the aircraft.
Implementation Method 1
a tuned absorber coupled to the load transferring member intermediate the opposed ends, the tuned absorber tuned to absorb engine noise of at least one predetermined frequency
Implementation Method 2
the tuned absorber has a damping member operatively coupled to the load transferring member and movable relative to the load transferring member at least along the longitudinal axis
Implementation Method 3
a viscoelastic layer connected to the damping member and to the load transferring member
Implementation Method 4
the hollow portion is filled with a viscous fluid operatively coupling the damping member to an inner surface of the load transferring member
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
An assembly for connecting an engine to an aircraft, including a first support configured to be structurally connected to the engine, a second support configured to be structurally connected to the aircraft, and a thrust link. The thrust link includes a load transferring member having opposed ends each connected to a respective one of the supports for transferring engine thrust loads from the engine to the aircraft along a longitudinal axis of the load transferring member. The opposed ends have a fixed position relative to each other. The thrust link further includes a tuned absorber coupled to the load transferring member intermediate the opposed ends. The tuned absorber is tuned to absorb engine noise of at least one predetermined frequency. A thrust link and a method for reducing a transfer of noise generated by the engine to the aircraft are also discussed.