• Proceedings of the Korea Association of Information Systems Conference
• /
• 2005.12a
• /
• pp.162-168
• /
• 2005

최근 새로운 수송망 설계를 통한 물류비 절감이 물류 관련 업체의 큰 이슈가 되고 있다. 하지만 일반적으로 행해지고 있는 수송망 설계는 대부분이 선박, 항공기, 열차 각각에 대해서만 고려되었으며 여러 가지 운송모드를 고려하는 복합운송망 설계는 극히 일부에 지나지 않았다. 이는 선박, 항공기, 열차를 모두 고려하여 수송망을 설계하기 위해서 필요한 운항 스케줄 정보가 산재되어 있어 복합운송망을 설계하기에는 많은 어려움이 따랐기 때문이다. 이러한 문제점을 해결하기 위해서는 모든 운송모드의 스케줄 데이터를 통합하여 제공할 수 있는 통합 데이터베이스 구축이 필요하다. 본 연구에서는 선박, 항공기, 열차에 대한 스케줄 정보를 제공하고 있는 정보원들을 분석하고 데이터 제공 방식을 조사하여 이를 모두 수용함으로써 데이터를 실시간으로 수집할 수 있는 에이전트 시스템의 설계를 수행하였다.

• Aerospace Engineering and Technology
• /
• v.1 no.1
• /
• pp.8-27
• /
• 2002

In this study, the load analysis of a composite canard aircraft is performed numerically. Excel visual basic program for PC is used to calculate aerodynamic coefficients, loads and moments etc.. The basic data required for the load analysis such as aircraft configuration and dimension, parts and its weight and coordinate etc. are obtained from Catia modeling, measurement or material density. Aircraft weight, center of gravity, inertia moment, structural design speeds, wing load distribution, forces and moments are evaluated by using these data. V-n diagram is also represented for selecting critical loads applied to the wing and fuselage. The V-n diagram is investigated to decide the flight envelope of canard aircraft for design speed VA, VC, VD and load factor +3.8G, -1.52G at maximum weight of 2,573 lbs and sea level. In the future, the results of the wing and fuselage load analysis is to represented by using selected critical loads.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.40 no.12
• /
• pp.1086-1092
• /
• 2012

It has been studied for DGPS/INS(Differential Global Positioning System/Inertial Navigation System) to offer the more precise and reliable navigation data with the aviation industry development. The flight performance evaluation of navigation system is very significant because the reliability of navigation data directly affect the safety of aircraft. Especially, the high-level navigation system, as DGPS/INS, need more precise flight performance evaluation method. The performance analysis is performed by comparing between the DGPS/INS navigation data and reference trajectory which is more precise than DGPS/INS. The GPS receiver, which is capable of post-processed CDGPS(Carrier-phase DGPS) method, can be used as reference system. Generally, the DGPS/INS is estimated the CG(Center of Gravity) point of aircraft while the reference system is output the position of GPS antenna which is mounted on the outside of aircraft. For this reason, estimated error between DGPS/INS and reference system will include the error due to lever arm. In order to more precise performance evaluation, it is needed to compensate the lever arm. This paper presents procedure and result of flight test which includes lever arm compensation in order to verify reliability and performance of DGPS/INS more precisely.

• Aerospace Engineering and Technology
• /
• v.8 no.1
• /
• pp.42-48
• /
• 2009

There are a number of factors affecting the continued airworthiness of composite structure. Unlike metal structure, damages made in manufacturing processes or maintenance repair procedures need to be considered. The different levels of degradation and damage, which may occur, must be considered for structural substantiation of static strength, stiffness, flutter, and damage tolerance. This can start with an evaluation of environmental effects for the particular composite material. Matrix-dominated composite properties, such as compressive strength, are most sensitive to moisture absorption and temperatures. Static strength substantiation includes the smaller damages that will not be detected in production or maintenance inspection while damage tolerance addresses larger damages that need to be repaired once discovered. In this paper, we intend to list the airworthiness regulations and advisory circular that are deemed closely related to the certification of composite airplanes.

• Aerospace Engineering and Technology
• /
• v.10 no.1
• /
• pp.183-192
• /
• 2011

The demand for weight saving and high performance of aircraft require the more uses of composite materials. However the complicate behaviors and various failure characteristics restrict usage of composite materials. Low-velocity impact damage is a major concern in the design of structures made of composite materials, because impact damage is hidden and cannot be detected by visual inspection. Especially, the reduction on compressive strength after impact is influenced by the ply delaminations introduced as damage by impact event. In this research, the numerical analysis was performed to investigate impact damage and compressive strength after impact. It was found that impact force history and compressive strength after impact calculated by the numerical analysis were compared and shown a good agreement with experimental results.

• Journal of Aerospace System Engineering
• /
• v.16 no.3
• /
• pp.35-41
• /
• 2022

UAM (Urban Air Mobility) is a new safe, secure, and more sustainable air transportation system for passengers and cargo in urban environments. Commercial operations of UAM are expected to start in 2025. Since production rates of UAM are expected to be closer to cars than conventional aircraft, the airworthiness methodology for UAM must be prepared for mass production. Composite materials are expected to be mainly used for UAM structures to reduce weight. In this paper, the composite material qualification method was derived and the materials were applied for small aircraft application. It is expected to reduce the airworthiness certification time by applying composite material qualification system and its database.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.48 no.9
• /
• pp.671-680
• /
• 2020

This paper describes an improved beam analysis for compound rotorcraft fuselage design. The present beam approach is capable of analyzing fuselage composed of stiffeners using equivalent layer methodology. Thickness of the skin and laminated layer approach are suggested based on the unified beam formulation. The analysis which considers an equivalent stiffener layer is performed for a fuselage with stiffeners and preliminary study about the specification of stiffeners is conducted and compared by the results using the existing software.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.35 no.1
• /
• pp.52-57
• /
• 2007

One of the hot issues in composite patching is to reduce the thermal residual stresses between composite patch and aluminum surface which occurs after bonding of composite patch. In this study, the edge crack patching is adopted for different curing cycles. For the analysis, three layer Mindlin plate elements are used, and Paris' law is adopted to predict the fatigue life of composite patch plate. The analysis results show a good agreement with the experimental fatigue life and this technique can be applied for the prediction of fatigue life of aircraft structures.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.47 no.7
• /
• pp.535-540
• /
• 2019

The coupling between different models for MDO (Multi-disciplinary Optimization) greatly increases the complexity of the computational framework, while at the same time increasing CPU time and memory usage. To overcome these difficulties, POD (Proper Orthogonal Decomposition) and RBF (Radial Basis Function) are used to solve the optimization problem of determining the thickness of composites and sandwich cores when composite sandwich structures are used as aircraft wing skin materials. POD and RBF are used to construct surrogate models for the wing shape and the load data. Optimization is performed using the objective function and constraint function values which are obtained from the surrogate models.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 1999.11a
• /
• pp.246-250
• /
• 1999

항공기 날개 및 동체의 보강재로 사용되는 스트링거가 압축하중을 받게되면 플렌지와 웹에서의 부분좌굴이 발생하고 이는 좌굴이 발생하지 않은 부분에 과도한 하중이 걸리게 하여 스트링거의 전체적인 하중지지능력을 현저히 감소시킨다. 이러한 손상의 형태가 크리플링(Crippling)이다. (중략)