• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.175-182
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• 2016

Recently, carbon fiber-reinforced composite is widely used in many aerospace applications. Among most of the aerospace vehicles, human-powered aircraft essentially uses it for minimizing the weight of the vehicle and gaining high stiffness to increase its efficiency. In this paper, main wing spar of the human-powered aircraft is investigated. Finite element models were created based on the baseline model built in 2013 to make analysis of cross-section of the spar with varying ply angles of each layer of the spar. Objective function, which is affected from bending rigidity, torsional rigidity, and strength ratio, was evaluated for every cases. The model of 2013 and present cases were put into comparison by values evaluated from objective function. From the comparison, it was concluded that there are more chances to improve the baseline model to make the vehicle better in stiffness and weight than the model of 2013.

• Proceeding of EDISON Challenge
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• 2012.04a
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• pp.45-48
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• 2012

본 연구는 인력기를 개발함에 있어서 이에 적합한 프로펠러의 형상을 설계하기 위하여 진행되었다. 인력기는 인간을 유일한 동력원으로 사용하기 때문에 적은 동력, 낮은 RPM을 가지고 비행을 하게 된다. 이에 따라 기존의 항공기와는 다른 특성 및 형상을 가지는 프로펠러 개발의 필요성이 인지되었다. 본 연구에서는 설계하고자 하는 인력기의 제원에 맞는 프로펠러의 특성을 설정한 뒤, 프로펠러의 블레이드를 수 개의 airfoil section으로 나누고, 각 섹션에 대한 공력 특성을 프로펠러 이론 및 Edison CFD를 통하여 계산 및 유추하였다. 이 계산 결과를 토대로 구한 각 airfoil section의 정보를 통하여 프로펠러의 형상을 얻어 낼 수 있었으며, 최종적으로 이를 ANSYS Fluent, CFX와 같은 상용 프로그램을 이용하여 분석함으로써 설계 전에 목표로 하였던 프로펠러의 성능에 도달하였는가를 확인할 수 있었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.4
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• pp.183-190
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• 2018

This paper presents optimization of the main spar of Human-Powered Aircraft (HPA) wing. Mass minimization was attempted, while considering large torsional deformation of the beam. Sequential Quadratic Programming (SQP) method was adopted as a relevant tool to conduct structural optimization algorithm. An inner diameter and ply thicknesses of the main spar were selected as the design variables. The objective function includes factors such as mass minimization, constant tip bending displacement, and constant tip twist of the beam. For estimation of bending and torsional deformation, the geometrically exact beam model, which is appropriate for large deflection, was adopted. Properties of the cross sectional area which the geometrically exact beam model requires were obtained by Variational Asymptotic Beam Sectional Analysis (VABS), which is a cross sectional analysis program. As a result, maintaining tip bending displacement and tip twist within 1.45%, optimal design that accomplished 7.88% of the mass reduction was acquired. By the stress and strain recovery, structural integrity of the optimal design and validity of the present optimization procedure were authenticated.