Variable Geometry Structure Actuator Tensioning Flexural Element
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Solution Overview
Problem
Existing variable geometry structures for gas turbine engines, such as those using shape memory materials, are limited by the need for temperature maintenance to retain positions and typically offer only two configurations, increasing complexity and operational constraints.
Innovation Solution
A variable geometry structure comprising a flexural element, a tensioning element with normal elastic properties, and an actuator that adjusts the tensioning element's load by pulling or pushing, allowing for multiple configurations without significant weight or complexity increase, including a free position, a first configuration where the flexural element is planar, and a second configuration where it is curved, with the actuator being hydraulically, pneumatically, or motor-driven.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If shape memory material is used to change geometry, then the geometry can be changed, but temperature must be maintained to retain the deployed position
Solution Approach 1:
The patent replaces the thermal field system (shape memory material requiring temperature maintenance) with a mechanical field system (tensioning element with actuator). The actuator applies mechanical tension to the tensioning element, which directly loads the flexural element to achieve and maintain the deployed position without requiring continuous thermal energy input.
Solution Approach 2:
The actuator pre-tensions the tensioning element to a specific level that corresponds to the desired deployed position. This preliminary mechanical action establishes the geometry change, and the elastic properties of the tensioning element maintain this position without requiring continuous energy input, unlike thermal systems that need sustained heating.
2Adaptability or versatility
If shape memory material is used, then geometry can be changed, but typically only two different positions are provided
Solution Approach 1:
The patent employs a continuous tensioning element that can be adjusted to various tension levels by the actuator, enabling the flexural element to assume multiple intermediate positions between fully retracted and fully deployed states. This continuous adjustment capability provides more than just two discrete positions, enhancing adaptability while keeping the structure relatively simple.
Solution Approach 2:
The actuator varies the tension parameter in the tensioning element continuously rather than in discrete steps, allowing the flexural element to achieve a range of geometric configurations. By changing the tension parameter, the system provides multiple positions without requiring complex multi-component mechanisms.
3Strength
If the flexural element is made thicker to withstand external loads, then structural integrity improves, but the overall structure cannot be bent as much
Solution Approach 1:
The patent divides the structural system into two separate functional elements: a thin flexural element dedicated to bending and shape change, and a tensioning element dedicated to providing structural support and load-bearing capacity. This segmentation allows each element to be optimized for its specific function without compromise.
Solution Approach 2:
The system combines two different structural elements (flexural element and tensioning element) into a composite structure where each material can be selected for its optimal properties. The flexural element can be made from materials optimized for flexibility and low bending stress, while the tensioning element provides the necessary tensile strength to handle external loads, achieving both high strength and high bending capability.
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
Enables smooth transitions between configurations, reduced strain on the flexural element, and enhanced structural integrity under external loads, allowing for adaptable geometry without excessive bending or rapid aerodynamic changes, suitable for various applications including gas turbine nozzles and airframe controls.
Implementation Method 1
a tensioning element that has a fixed length and consists of a material with normal elastic properties
Data Source
Figure 1~3
Figure 4~7
AI summary
A variable geometry (2) structure comprising: an flexural element (4); a tensioning element (6) connected to the flexural element (8); and an actuator (12) for adjusting the tensioning element (6) to change the load placed on the flexural element (4), thereby changing the geometry of the structure (2).