Marman clamp shape memory alloy actuator release
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Solution Overview
Problem
Marman clamps used in space applications require multiple redundant release mechanisms due to the risk of failure, adding weight and complexity to space vehicles.
Innovation Solution
A Marman clamp with a shape memory alloy actuator that automatically changes positions from closed to open or vice versa using temperature or applied force, eliminating the need for redundant release mechanisms by using SMA pins or tubes to control the clamping action.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple redundant release mechanisms are used in Marman clamps, then reliability is improved, but weight and device complexity increase
Solution Approach 1:
The patent replaces traditional pyrotechnic and mechanical release mechanisms with a shape memory alloy (SMA) actuator that uses thermodynamic phase transformation. The SMA pin transforms from martensite to austenite phase when heated, automatically pushing the V-segment to release the clamp without requiring complex mechanical release systems or multiple redundant mechanisms.
Solution Approach 2:
The invention utilizes the phase transition property of shape memory alloys. The SMA pin remains in martensite phase at low temperatures allowing the clamp to stay closed, and transitions to austenite phase when heated above its transformation temperature, causing automatic expansion and push of the V-segment to open the clamp. This phase transition provides reliable operation with a single mechanism.
2Reliability
If pyrotechnic-based release mechanisms are used, then reliability is improved, but weight increases
Solution Approach 1:
The patent replaces heavy pyrotechnic mechanisms with a lightweight shape memory alloy actuator. The SMA pin provides sufficient force through phase transition to push the V-segment and release the clamp, eliminating the need for pyrotechnic charges, igniters, and associated safety mechanisms, thereby significantly reducing overall system weight.
Solution Approach 2:
The invention changes the operating parameter from chemical energy (pyrotechnics) to thermal energy (phase transition). By controlling the temperature of the SMA pin through external heating or environmental temperature changes, the clamp can be reliably released without the weight penalty of pyrotechnic systems.
3Reliability
If multiple redundant release mechanisms are used, then reliability is improved, but the space vehicle becomes more complex
Solution Approach 1:
The patent replaces complex mechanical and pyrotechnic release systems with a simple shape memory alloy actuator that responds automatically to temperature changes. This single SMA-based mechanism eliminates the need for multiple redundant release systems, simplifying the overall space vehicle system while maintaining reliable operation.
Solution Approach 2:
The SMA actuator provides self-service operation by automatically transforming in response to temperature changes. When the space vehicle experiences temperature variations (such as during orbital day/night cycles or upon separation from the launch vehicle), the SMA pin automatically transitions phases and releases the clamp without requiring complex control systems or multiple redundant mechanisms.
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 solution reduces weight and complexity by providing a reliable, self-tightening mechanism that is not damaged during release, allowing for efficient and lightweight clamping without the need for pyrotechnic-based mechanisms.
Implementation Method 1
A Marman clamp with a shape memory alloy actuator that automatically changes positions from closed to open or vice versa using temperature or applied force
Implementation Method 2
maintaining a clamp in a first position until a temperature of the shape memory alloy actuator passes a martensitic transition temperature, which is when the clamp moves to the second position
Data Source
AI summary
A Marman clamp is disclosed. The Marman clamp includes a release mechanism with either pins or tubes formed with a shape memory alloy. The release mechanism opens and closes the clamp depending on the temperature of the pins or tubes. The temperature of the pins or tubes may be based on whether a space vehicle including the clamp is in a direct line of sight of radiation from the sun. Alternatively, a heat source may control the temperature of the pins or tubes. The Marman clamp may also open and close as a result of an independent force applied to the release mechanism.