scholarly journals Bionic Stiffener Layout Optimization with a Flexible Plate in Solar-Powered UAV Surface Structure Design

2019 ◽  
Vol 9 (23) ◽  
pp. 5196 ◽  
Author(s):  
You Ding ◽  
Zhou Zhou ◽  
ZhengPing Wang ◽  
HongJun Liu ◽  
KeLei Wang
Keyword(s):  
Surface Structure ◽  
Structure Design ◽  
Flexible Plate ◽  
Long Span ◽  
L System ◽  
Final Design ◽  
Stiffener Layout ◽  
Solar Powered ◽  
Searching Method ◽  
Stiffener Layout Optimization

A cellular-based evolutionary topology optimization scheme over a small curvature big contour wing surface is proposed for the design of an ultralight surface structure. Using this method, a ground-structure technique is first applied to obtain homogeneous mesh generation with a predefined weight value over the design domain. Secondly, the stiffener path’s description is guided by a modified map L system topology method that simulates the growth of the bionic branch, and the structural components are obtained by the specified searching method according to weights of the previous mesh vertexes. Thirdly, an optimal curved stiffener layout is achieved using an agent-based algorithm to create individual instances of designs based on a small number of input parameters. These parameters can then be controlled by a genetic algorithm to optimize the final design according to goals like minimizing weight and structural weakness. A comparison is implemented for long-span panel stiffener layout generation between an initial straight case and a bionic optimal case via our method, thereby indicating the significant improvement of the buckling loads by steering the stiffener’s path. Finally, this bionic method is applied to the wing box structure design and achieves remarkable weight loss at last.

Hierarchical Nano/Micro-structured Surfaces with High Surface Area/Volume Ratios

2021 ◽  
pp. 1-36
Author(s):  
Ketki Lichade ◽  
Yizhou Jiang ◽  
Yayue Pan
Keyword(s):  
Surface Structure ◽  
Surface Area ◽  
Light Trapping ◽  
High Surface ◽  
High Surface Area ◽  
Three Dimensional ◽  
Structure Design ◽  
Surface Structures ◽  
Structured Surfaces ◽  
Design And Manufacture

Abstract Recently, many studies have investigated additive manufacturing of hierarchical surfaces with high surface area/volume (SA/V) ratios, and their performance has been characterized for applications in next-generation functional devices. Despite recent advances, it remains challenging to design and manufacture high SA/V ratio structures with desired functionalities. In this study, we established the complex correlations among the SA/V ratio, surface structure geometry, functionality, and manufacturability in the Two-Photon Polymerization (TPP) process. Inspired by numerous natural structures, we proposed a 3-level hierarchical structure design along with the mathematical modeling of the SA/V ratio. Geometric and manufacturing constraints were modeled to create well-defined three-dimensional hierarchically structured surfaces with a high accuracy. A process flowchart was developed to design the proposed surface structures to achieve the target functionality, SA/V ratio, and geometric accuracy. Surfaces with varied SA/V ratios and hierarchy levels were designed and printed. The wettability and antireflection properties of the fabricated surfaces were characterized. It was observed that the wetting and antireflection properties of the 3-level design could be easily tailored by adjusting the design parameter settings and hierarchy levels. Furthermore, the proposed surface structure could change a naturally-hydrophilic surface to near-superhydrophobic. Geometrical light trapping effects were enabled and the antireflection property could be significantly enhanced (>80% less reflection) by the proposed hierarchical surface structures. Experimental results implied the great potential of the proposed surface structures for various applications such as microfluidics, optics, energy, and interfaces.

scholarly journals Design of a Hand-Launched Solar-Powered Unmanned Aerial Vehicle (UAV) System for Plateau

2020 ◽  
Vol 10 (4) ◽  
pp. 1300 ◽  
Author(s):  
Xin Zhao ◽  
Zhou Zhou ◽  
Xiaoping Zhu ◽  
An Guo
Keyword(s):  
Low Temperature ◽  
Conceptual Design ◽  
Unmanned Aerial Vehicle ◽  
Design Method ◽  
Structure Design ◽  
Control Law ◽  
Trajectory Tracking Control ◽  
Plateau Area ◽  
Aerial Vehicle ◽  
Solar Powered

This paper describes our work on a small, hand-launched, solar-powered unmanned aerial vehicle (UAV) suitable for low temperatures and high altitudes, which has the perpetual flight potential for conservation missions for rare animals in the plateau area in winter. Firstly, the conceptual design method of a small, solar-powered UAV based on energy balance is proposed, which is suitable for flight in high-altitude and low-temperature area. The solar irradiance model, which can reflect the geographical location and time, was used. Based on the low-temperature discharge test of the battery, a battery weight model considering the influence of low temperature on the battery performance was proposed. Secondly, this paper introduces the detailed design of solar UAV for plateau area, including layout design, structure design, load, and avionics. To increase the proportion of solar cells covered, the ailerons were removed and a rudder was used to control both roll and yaw. Then, the dynamics model of an aileron-free layout UAV was developed, and the differences in maneuverability and stability of aileron-free UAV in plateau and plain areas were analyzed. The control law and trajectory tracking control law were designed for the aileron-free UAV. Finally, the flight test was conducted in Qiangtang, Tibet, at an altitude of 4500 m, China’s first solar-powered UAV to take off and land above 4500 m on the plateau in winter (−30 °C). The test data showed the success of the scheme, validated the conceptual design method and the success of the control system for aileron-free UAV, and analyzed the feasibility of perpetual flight carrying different loads according to the flight energy consumption data.

Relaxation of Residual Stress in Bent GaN Film on Sapphire Substrate by Laser Treatment With an Optimized Surface Structure Design

2013 ◽  
Vol 60 (2) ◽  
pp. 767-770
Author(s):  
Chih Hua Chen ◽  
M.-H. Liao ◽  
Li Cheng Chang ◽  
Ssu Chieh Kao ◽  
M.-Y. Yu ◽  
...  
Keyword(s):  
Residual Stress ◽  
Surface Structure ◽  
Laser Treatment ◽  
Sapphire Substrate ◽  
Structure Design ◽  
Gan Film

Optimal Design for Photovoltaic and Photothermal Hybrid Solar Cells of Solar Powered Aircraft

2013 ◽  
Vol 724-725 ◽  
pp. 57-62
Author(s):  
Kang Wen Sun ◽  
Min Ni
Keyword(s):  
Design Method ◽  
Photovoltaic Cells ◽  
Optimal Solution ◽  
Structure Design ◽  
Maximum Power ◽  
Wing Surface ◽  
Mass Ratio ◽  
Hybrid Energy ◽  
Solar Powered ◽  
Junction Structure

Cell temperature can reach as high as 70 oC while working, using only photovoltaic battery in the solar plane will result in a waste of energy. Combined with the wing configuration, a hybrid energy design method with higher efficiency is presented: photovoltaic cells will be distributed on the wing surface and photothermal cells will be arranged in the wing box section. The back of photovoltaic battery can be used as high temperature heat source and the lower wing surface can be a low temperature cooling source. Through the research of photovoltaic cells maximum power output, the envelope method ensures the output power, improves the power tracking reliability, and reduces difficulty in the design. The structure design of thermoelectric battery P-N junction is optimized by using the maximum power and maximum power to-mass ratio as objective function. The optimal solution of P-N junction structure of a certain type thermoelectric battery is given for acquiring maximum power-to-mass ratio.

Research of Temperature Field of Long Span Concrete Box Girder Bridge Caused by Solar Radiation

2012 ◽  
Vol 256-259 ◽  
pp. 1635-1639
Author(s):  
Cun Ren Jiang ◽  
Jian Min Ren ◽  
Zhuo Ling Wang
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
Solar Radiation ◽  
Structure Design ◽  
Box Girder ◽  
Qinghai Province ◽  
Long Span ◽  
Concrete Box Girder ◽  
Girder Bridge ◽  
Bottom Slab

When stimulate temperature field of concrete box girder caused by solar radiation with ANSYS, it’s feasible to turn boundary conditions to third boundary condition. Taking Ping'an Huangshui River Super-large Bridge in Qinghai Province for example, the research analyzes box girder temperature field distribution and deduces realistic temperature gradient mode by comparing calculations with measurements. Calculations show that bottom slab of box girder also has quite big temperature gradient which should be taken seriously in bridge structure design.

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