Aircraft Engine Actuator With Viscoelastic Damping for High Vibration
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Solution Overview
Problem
Aircraft engine actuators fail to effectively dampen high vibrations exceeding 20 Gs, leading to resonance, test failures, and weight increases due to inadequate damping capabilities, necessitating a solution to enhance vibration attenuation without significant weight penalties.
Innovation Solution
The aircraft engine assembly incorporates a tubular base layer with a visco-elastic layer on the piston rod, selected based on vibration frequencies, which provides free layer and constrained layer damping to dissipate energy and reduce vibration responses, using adhesives to secure the visco-elastic material and potentially including metallic materials for the base and constrained layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional actuators are used without visco-elastic damping layers, then the device complexity remains low, but the actuators fail to dampen high vibrations exceeding 20 Gs and resonate at engine operating frequencies
Solution Approach 1:
The actuator incorporates a composite structure with a tubular base layer and a visco-elastic layer disposed on the base layer. This composite construction combines the structural integrity of the base layer with the vibration-damping properties of the visco-elastic material, enabling the actuator to withstand high vibrations exceeding 20 Gs while maintaining structural strength.
Solution Approach 2:
The visco-elastic layer's properties are selected in accordance with at least a vibration frequency of interest, allowing the damping characteristics to be optimized for specific engine operating frequencies. This parameter-based selection enables targeted vibration attenuation at resonant frequencies without requiring complex active control systems.
2Reliability
If redesign efforts are made to improve damping capability to meet certain damping ratio goals, then vibration damping improves, but significant weight additions occur
Solution Approach 1:
The visco-elastic layer functions as a thin film or layered structure that provides damping capability without requiring bulky additional components. This thin-film approach achieves the required damping ratio goals while minimizing weight addition compared to traditional redesign approaches.
Solution Approach 2:
The composite construction of the tubular base layer with the visco-elastic layer provides high damping capability relative to the added weight. The visco-elastic material's inherent damping properties allow the structure to meet damping ratio goals without the significant weight penalties associated with conventional reinforcement methods.
3Object-affected harmful factors
If the actuator natural frequencies fall in the engine operating range, then resonance occurs leading to high responses, but changing the actuator design to shift frequencies adds complexity and weight
Solution Approach 1:
Instead of attempting to shift the actuator's natural frequencies away from engine operating ranges (which would require complex redesign), the invention accepts the frequency overlap and uses the visco-elastic layer to dissipate the vibrational energy that causes resonance. This converts the harmful resonant response into manageable energy dissipation through the damping layer.
Solution Approach 2:
The visco-elastic layer's damping characteristics are selected based on the vibration frequency of interest, allowing the system to maintain its natural frequency within the engine operating range while effectively attenuating the resonant responses through frequency-targeted damping material selection.
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 configuration significantly reduces high vibration responses, enabling actuators to pass qualification tests without failures, offering weight reduction opportunities, improved damping, and reduced flammability risks while shortening the product cycle.
Implementation Method 1
a visco-elastic layer disposed on the tubular base layer and selected in accordance with at least a vibration frequency of interest
Implementation Method 2
provides free layer and constrained layer damping to dissipate energy and reduce vibration responses
Implementation Method 3
the visco-elastic layer is adhesively disposed on an interior facing surface of the tubular base layer
Data Source
Figure 1~2
Figure 3A~3B
Figure 4A~4B
AI summary
An actuator (13) is provided for an aircraft engine and includes a tubular base layer (30) and a visco-elastic layer (40) adhesively disposed on the tubular base layer (30). An aircraft engine comprising an engine case (11), a cowl door (12) and such an actuator (13) is also provided.