Shape-Memory Alloy Missile Control Surfaces for Drag Reduction
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Solution Overview
Problem
Traditional aerodynamic control surfaces for missiles and vehicles introduce additional drag forces and require significant space for retraction, limiting their efficiency and compactness.
Innovation Solution
The use of small, retractable aerodynamic control surfaces made of shape-memory alloy that can be selectively extended and retracted by heating, allowing them to conform to the vehicle's surface when not in use, thereby reducing drag and space requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional aerodynamic control surfaces are extended from the vehicle body, then flight path control is achieved, but additional drag forces and space requirements increase
Solution Approach 1:
The control surfaces transition from a static extended position to a dynamic reconfigurable state. By using shape-memory alloy, the surfaces can dynamically change their configuration between extended (for control) and retracted/conformed (for reduced drag), allowing the system to adapt its aerodynamic profile based on operational requirements
Solution Approach 2:
The invention changes the physical state of the control surface material through temperature control. By heating the shape-memory alloy above its transition temperature, the material transforms from a conformal state to an extended state, enabling control surface deployment without mechanical actuators. This parameter change (temperature) directly controls the geometric configuration
2Object-generated harmful factors
If traditional retractable aerodynamic control surfaces are used, then drag is reduced when not in use, but additional mechanisms and volume are required
Solution Approach 1:
The invention replaces complex mechanical retraction mechanisms (hinges, actuators, linkages) with a thermal-field-based shape-memory alloy system. The control surfaces are heated through resistive heating elements or other thermal methods, causing the material to spontaneously change shape and extend or retract based on temperature, eliminating the need for traditional mechanical retraction systems
Solution Approach 2:
The shape-memory alloy control surfaces are self-actuating through thermal stimulation. When heated, the material automatically transitions from a conformal stowed position to an extended control position without requiring external mechanical actuators. The material's inherent shape-memory properties enable it to service its own deployment and retraction functions
3Loss of time
If shape-memory alloy control surfaces are heated to extend, then response time is decreased, but energy consumption increases
Solution Approach 1:
Instead of heating the entire control surface uniformly or continuously, the system applies thermal energy selectively and temporarily. Heating elements are activated only when and where needed to trigger the shape-memory effect, and the heating duration is limited to the minimum time required for the material transition. This partial action reduces overall energy consumption while maintaining fast response time
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 solution enables precise control of a vehicle's flight path with reduced drag and space consumption, as the shape-memory alloy control surfaces can be quickly deployed and stowed, improving response time and aerodynamic efficiency.
Implementation Method 1
The control surfaces 14 are made of a material that includes a shape-memory alloy. Heating the control surfaces 14 causes the shape-memory alloy to change shape.
Implementation Method 2
Heating the shape-memory alloy activates the control surface to move away from the surface of the body and to extend into the airflow around the body
Data Source
Figure 1
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Figure 4~5
AI summary
A control system (10) for a missile (12) includes a plurality of control surfaces (14) that can be arrayed across a surface (16) of the missile body (18), and a controller (30) connected to the control surfaces (14) to selectively move the control surfaces (14) between an aerodynamic stowed position where the control surfaces conform to the surface of the body, and a deployed control position removed from the aerodynamic stowed position where the control surfaces extend from the surface of the body to interact with airflow (20) over the body. The control surfaces are made of a material that includes a shape-memory alloy. Heating the control surfaces causes the shape- memory alloy to move the control surfaces from the aerodynamic stowed position to the deployed control position. By selectively extending and retracting the control surfaces, the control system provides the ability to control the missile's direction of travel or to reduce roll about a longitudinal axis (22) of the body (18).