A Single Actuator Mechanism for Airfoil Shape Morphing

Author(s):  
Andrew Ellis ◽  
Cong Zhu (John) Sun ◽  
Fengfeng (Jeff) Xi ◽  
Amin Moosavian

Presented in this paper is a single actuator mechanism for airfoil shape morphing. The said mechanism is designed as a linkage array that is driven by one actuator to provide multiple output points along the entire airfoil shape. This mechanism consists of two components, namely the shape adaptation linkage (SAL) and the connector linkage. Each connector is made up of a passive camber connector (PCC) or an active camber connector (ACC). The PCC conditions the output of an SAL while the ACC serves to create the camber morphing effect. The design method is proposed with three steps: Camber Mapping, Shape Adaptation Linkage Synthesis, and Connector Synthesis. The proposed method has been applied to design a number of NACA airfoils with camber morphing to demonstrate the effectiveness.

Author(s):  
Y-A Yao ◽  
H-S Yan

This paper proposes a novel concept for reducing driving torque fluctuations of planar linkages by the application of non-circular gears. The circular gears normally used in gear linkage mechanisms are replaced by a pair of non-circular gears. The design method includes two individual stages: linkage synthesis and gear ratio synthesis. An optimization model is developed for determining the appropriate transmission ratio function of the non-circular gear pair to meet user-specified requirements and constraints. Two examples are given to demonstrate this method and to verify its feasibility.


Author(s):  
Judy M. Vance ◽  
Denis Dorozhkin

This manuscript outlines a novel approach to the design of compliant shape-morphing structures using constraint-based design method. Development of robust methods for designing shape-morphing structures is the focus of multiple current research projects, since the ability to modify geometric shapes of the individual system components, such as aircraft wings and antenna reflectors, provides the means to affect the performance of the corresponding mechanical systems. Of particular interest is the utilization of compliant mechanisms to achieve the desired adaptive shape change characteristics. Compliant mechanisms, as opposed to the traditional rigid link mechanisms, achieve motion guidance via the compliance and deformation of the mechanism’s members. The goal is to design a single-piece flexible structure capable of morphing a given curve or profile into a target curve or profile while utilizing the minimum number of actuators. The two primary methods prevalent in the design community at this time are the pseudo-rigid body method (PRBM) and the topological synthesis. Unfortunately these methods either tend to suffer from a poor ability to generate potential solutions (being more suitable for the analysis of existing structures) or are susceptible to overly-complex solutions. By utilizing the constraint-based design method (CBDM) we aim to address those shortcomings. The concept of CBDM has generally been confined to the Precision Engineering community and is based on the fundamental premise that all motions of a rigid body are determined by the position and orientation of the constraints (constraint topology) which are placed upon the body. Any mechanism motion path may then be defined by the proper combination of constraints. In order to apply the CBDM concepts to the design and analysis of shape-morphing compliant structures we propose a tiered design method that relies on kinematics, finite element analysis, and optimization. By discretizing the flexible element that comprises the active shape surface at multiple points in both the initial and the target configurations and treating the resulting individual elements as rigid bodies that undergo a planar or general spatial displacement we are able to apply the traditional kinematics theory to rapidly generate sets of potential solutions. The final design is then established via an FEA-augmented optimization sequence. Coupled with a virtual reality interface and a force-feedback device this approach provides the ability to quickly specify and evaluate multiple design problems in order to arrive at the desired solution.


Author(s):  
Cosima du Pasquier ◽  
Pascal Koller ◽  
Tino Stankovic ◽  
Kristina Shea

Abstract With advances in 3D printing and digital fabrication an opportunity is presented to realize highly customized designs whose shape can change and adapt to facilitate their functionality. A computational design method to determine the configuration of 2D pneumatic shape morphing lattices using a direct search method is implemented and assessed. The method is tested using a Kagome unit cell lattice structure, which is particularly well suited for shape morphing. To achieve shape change, beams are replaced by linear actuators such as those found in pneumatic 4D printing, whose number and placement are optimized to replicate a given target shape. The actuator placement and deformation accuracy are given for four main curvature changes: linear, convex, concave and the transition from one to the other. The results are assessed in terms accuracy of deformation and computational effort. It is shown that the method proposed produces structures that can replicate complex shape changes within 1% of the desired shape. Reducing the number of actuators for robustness purposes is shown to affect the results minimally.


2021 ◽  
Author(s):  
Jebin Biju ◽  
Georges Fadel ◽  
Suyi Li ◽  
Oliver Myers

Abstract Thin bistable composite laminates can be used for shape morphing applications by virtue of their material properties and asymmetric ply layup. These laminates are called bistable because they can be snapped into two or more stable shapes. A single bistable patch can result in simple cylindrical shapes and when multiple such patches are assembled into a single multi-patch laminate they result in more complex shapes and multiple stable shapes that can find wide practical use in shape morphing applications. Analytical models exist that can approximate the stable shapes of the laminates from the input of material properties and laminate geometry. And these models correlate with FEA and experiment to a satisfactory degree and could be used for the design of multi patch laminates. In this research, we make use of these analytical models that solve for a four-patch grid laminate and create a design method based on optimization to solve the reverse problem to arrive at the laminate parameters given the target shape(s). Two approaches are presented wherein one targets a single stable shape and the other targets two stable shapes which are the shapes before and after snap through. This work would be useful to understand how multi-patch laminates could be designed using optimization.


2005 ◽  
Author(s):  
Michael Szczepkowski ◽  
Kelly Neville ◽  
Ed Popp
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document