A novel non-embedded, adjustable, and flexible shape memory alloy actuator for variable-area exhaust nozzle actuation

Area of Science:

• Aerospace Engineering
• Materials Science
• Mechanical Engineering

Background:

• Conventional actuators for variable-area exhaust nozzles (hydraulic, electric motors) are heavy, large, and complex.
• Shape memory alloys (SMAs) offer advantages like light weight and structural simplicity but have limitations in radial space and fixed curvature.
• Existing SMA actuators lack adjustable actuating displacement after design.

Purpose of the Study:

• To develop a novel non-embedded, adjustable, and flexible SMA actuator for variable-area exhaust nozzle actuation.
• To address the limitations of conventional and existing SMA actuators.
• To enhance the performance and adaptability of exhaust nozzle actuation systems.

Main Methods:

• Development of a novel non-embedded, adjustable, and flexible SMA actuator.
• Presentation of an analytical model to predict mechanical performance.
• Experimental investigation of the flexible SMA actuator's mechanical performance.
• Design, fabrication, and testing of a proof-of-concept variable-area exhaust nozzle using the flexible SMA actuator.
• Utilizing image recognition for capturing nozzle movement and calculating area changes.

Main Results:

• The developed SMA actuator demonstrates flexibility, capable of bending from -90° to +90°.
• Actuating displacement is adjustable by modifying the number of hinged units.
• The variable-area exhaust nozzle achieved a 64.4% area change, surpassing previous SMA-actuated nozzle studies (max 40%).

Conclusions:

• The novel flexible SMA actuator overcomes limitations of conventional and existing SMA actuators.
• The actuator's adjustability and flexibility are validated through analytical modeling and experimental testing.
• This innovative actuator significantly enhances the performance of variable-area exhaust nozzles for aeroengines.