Abstract
Research and/or Engineering Questions/Objective
Aerodynamic forces influence on the vehicle performances by affecting the loads on the tire, and these forces depend significantly on the vehicle’s external shape. Wings are mounted on ground vehicles to enhance the aerodynamic effects and thus realizing improvements in the performance of the vehicle such as higher cornering speeds and shorter braking distance while minimizing any increase in the vehicle’s weight. In this study, soft morphing wings which form seamless bendable and twistable trailing edge were presented for realizing the modification of the wing shape to produce higher aerodynamic performance.
Methodology
In this work, the trailing edge of the wing consists of a polymer matrix embedded with multi-layered structures which are composed of a layer of a woven of the shape memory alloy (SMA) wire and the glass fibers and a layer of glass fiber fabric. The axial deformation of the SMA wires generate forces causing a bending and twisting deformation by selectively morphing different sections of the wing. In order to evaluate the aerodynamic performance of this morphing wing, the coastdown test method which measures the speed and travelled distance until the vehicle stops and the coasting condition was used to determine the modification of the aerodynamics by the morphing wing.
Results
In the paper, the fabrication of the morphing wing and its adaptation to the small-scale vehicle are presented. The actuation behavior of the actuator for different modes of actuation is described which is caused by the thermomechanical loads generated by the SMA wires. Also, driving tests of the small-scale vehicle is conducted using the coastdown method, and the drag coefficients from the practical test are calculated.
Limitations of this study
A limitation of the current study is the limited scale of the vehicle model. Furthermore, the driving condition of the road test was conducted based on the short distance coasting method since the limitation of the testing area.
What does the paper offer that is new in the field including in comparison to other work by the authors?
As a first attempt to investigate the evaluation of the soft morphing wing for the small-scale vehicle, the road test was conducted in this paper.
Conclusions
This paper describes the practical considerations regarding the implementation of the SMA-based morphing wing on a small-scale ground vehicle to derive the aerodynamic effect in driving condition. The actuation behavior of the wing is introduced and the modification of the running resistance of the small-scale vehicle is experimentally derived.
Key Words : Aerodynamic Force, Coastdown Test, Morphing Wing, Shape Memory Alloy