Morphing Surface Stiffness Optimization for Aerodynamic Accuracy
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Solution Overview
Problem
Conventional morphing aerospace structures with constant thickness surfaces require a large number of actuation points to achieve accurate morphing, which increases complexity and error, especially when loading or control points are asymmetrically defined, limiting their morphing accuracy.
Innovation Solution
Designing a morphing waverider with a controllably morphable lower surface of varying stiffness, achieved through methods such as varying rib density, honeycomb structure thickness, material modulus, or bimetallic laminates, allowing for improved morphing accuracy and reduced control points by optimizing surface thickness using finite element analysis and gradient cost functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of actuation points are used to improve morphing accuracy, then position precision improves, but device complexity increases
Solution Approach 1:
The patent applies local quality by varying the stiffness of different regions of the morphing surface rather than using uniform stiffness throughout. This is achieved through spatially varying material properties or structural characteristics, allowing certain areas to be more compliant while others provide structural support, thereby reducing the number of actuation points needed while maintaining overall morphing accuracy.
Solution Approach 2:
The patent changes the physical parameter of surface stiffness from a constant value to a spatially varying parameter. By optimizing the stiffness distribution across the surface, the system achieves better morphing control with fewer actuators, as the varying stiffness allows for more efficient deformation propagation and shape control.
2Ease of manufacture
If surface thickness is kept constant throughout, then manufacturing simplicity is maintained, but morphing accuracy deteriorates
Solution Approach 1:
The patent transitions from uniform surface thickness to locally varied thickness, where different regions of the surface have optimized thickness values. Thinner regions allow for greater flexibility and deformation, while thicker regions provide structural support, enabling accurate morphing with reduced manufacturing complexity compared to alternative approaches.
Solution Approach 2:
The patent introduces dynamic characteristics to the surface structure by allowing the effective stiffness to vary spatially, creating a dynamically adaptable structure that can achieve desired morphing shapes more accurately while maintaining reasonable manufacturing simplicity through systematic design approaches.
3Adaptability or versatility
If the skin is made thin and flexible to enable morphing, then adaptability improves, but structural strength deteriorates
Solution Approach 1:
The patent applies local quality by creating a non-uniform stiffness distribution where the effective thickness or material properties vary across the surface. This allows regions requiring flexibility for morphing to be thinner and more compliant, while regions requiring structural support maintain greater thickness and stiffness, thereby resolving the contradiction between adaptability and strength.
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 approach significantly reduces morphing error and simplifies the control system while maintaining or improving aerodynamic performance, with 3-D surfaces benefiting more than 2-D surfaces, by allowing a balance between control system complexity, manufacturing complexity, and morphing error.
Implementation Method 1
the lower surface is controllably morphable and includes a stiffness that varies across the extent of the surface... The stiffness of the lower surface is configured to lower position error of the surface when actuated by the one or more actuators
Data Source
AI summary
A method of designing a morphable aerodynamic surface includes discretizing and parameterizing a model of a morphable surface to create a function to optimize; utilizing finite element analysis to solve for displacements and associated errors at an initialization point; and iteratively calculating a gradient cost function, define step size and search direction, step according to defined step size and search direction, and recalculate displacements and associated errors to converge on final thickness vector.