• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.20 no.5
• /
• pp.605-611
• /
• 2019

The fuel sloshing due to the rapid manoeuvre of the aircraft causes significant loads on internal components, which may break components or piping. In particular, a significant load is applied to the joint of the external fuel tank by sloshing movement, which may affect the safety of the aircraft when the joint of the external fuel tank is damaged. Therefore, in order to improve the survivability of aircraft and crew members, the design of external fuel tanks, and joints should be performed after evaluating the sloshing load through a numerical analysis of the fuel sloshing conditions. In this paper, a numerical analysis was performed on the sloshing test of the external fuel tank for rotorcraft. ALE (Arbitrary Lagrangian Eulerian) technique was used, and the test conditions specified in the U.S. Military Specification (MIL-DTL-27422D) was applied as the conditions for numerical analysis. As a result of the numerical analysis, the load on the joint of the external fuel tank was calculated. Moreover, the effects of sloshing movement on structural soundness were assessed through analysis of stress levels and margin of safety on metal fittings and composite containers.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.25 no.4
• /
• pp.130-140
• /
• 2017

Lightning protective design of an aircraft fuel system is closely related to the safety of the flight. Recently, composite material in building an aircraft becomes more important because it can reduce the weight of the aircraft. The composite materials decrease the protection against the effect of lightning. Lightning protective design of metal material aircraft has been researched for a long time and the design technique has been announced widely. However, research on the lightning protective design using composite material aircraft is very limited. In this study, lightning protective design for fuel tank structural component, access cover, fuel filler cap and drain valve in carbon fiber composite material aircraft have been presented. To show the compliance with FAA airworthiness standard regarding the presented protection designs, three steps, including lightning strike analysis, lightning environment analysis and certification test, were conducted in accordance with FAA AC 20-53.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.06a
• /
• pp.1402-1405
• /
• 2003

The main object of this study was evaluated by the delamination damage for fiber stacking angle. Therefore, this work need to compare the shape of delamination for a different fiber stacking angie. So this study uses a method of fatigue test which was created [0]$_2$,[+45]$_2$[90]$_2$. The extension of the delamination zone formed between aluminium alloy and glass fiber-adhesive layer were measured by an ultrasonic C-scan image. As a result, the shapes of delamination zone don't depend upon the crack propagation. We could know that the delamination zone grew interaction between stress flow of fiber layer and crack driving force. Hence, the existing study were applied to the stress transfer, fiber bridging effect, delaminantion growth rate should need to the develop useful factor because of change of fiber stacking angle.

• The KSFM Journal of Fluid Machinery
• /
• v.15 no.6
• /
• pp.11-17
• /
• 2012

The one way fluid structure interaction analysis on advanced propeller blade for next generation turboprop aircraft. HS1 airfoil series are selected as a advanced propeller blade airfoil. Adkins method is used for aerodynamic design and performance analysis with respect to the design point. Adkins method is based on the vortex-blade element theory which design the propeller to satisfy the condition for minimum energy loss. propeller geometry is generated by varying chord length and pitch angle at design point. Blade sweep is designed based on the design mach number and target propulsion efficiency. The aerodynamic characteristics of the designed Advanced propeller were verified by CFD(Computational Fluid Dynamic) and showed the enhanced performance than the conventional propeller. The skin-foam sandwich structural type is adopted for blade. The high stiffness, strength carbon/epoxy composite material is used for the skin and PMI(Polymethacrylimide) is used for the foam. Aerodynamic load is calculated by computational fluid dynamics. Linear static stress analysis is performed by finite element analysis code MSC.NASTRAN in order to investigate the structural safety. The result of structural analysis showed that the design has sufficient structural safety. It was concluded that structural safety assessment should incorporate the off-design points.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.12 no.1
• /
• pp.8-18
• /
• 1988

In the composite structures or the concrete structures, to analyze stress concentration factor, stress distributions and fracture mechanics of them under forces by photoelastic experiment, it is natural that to develope photoelastic model material for them is surely necessary. Thus, the orthotropic photoelastic model material for the transparent type photoelastic device was developed in the paper, it is called Copper Fiber Epoxy Composite and abbreviated as E.F.E.C. It was found that C.F.E.C. developed in this paper was satisfied with the properties of photoelastic model material that the photoelastic model material should have and that C.F.E.C. had completely properties of composite material. It is thought that C.F.E.C. can be applied to both medical engineering for modeling biological tissue and to the aerospace industry as orthotropic photoelastic material.

• Composites Research
• /
• v.26 no.3
• /
• pp.195-200
• /
• 2013

This study aims to detecting and analyzing the defects of damaged carbon fiber reinforced composites after impacts, particularly focusing on barely visible impact damages. The impact test was progressed by a drop-weight machine and applied to introduce simulated damages on laminated composites used in aircrafts. Various nondestructive testing (NDT) techniques were applied to identify the defects on the specimens with different levels of impact energies. Based on the measurements data, the levels of the barely visible impacts, and the applicability and effectiveness of the detection methods were discussed. Generally, the results demonstrated that their inner damages contained bigger footprints than those on the surfaces. However, when the damage energy was low, it was found that the inner damage size could be smaller than those appeared on the surfaces.

• Journal of the Korean Society of Industry Convergence
• /
• v.24 no.6_2
• /
• pp.883-890
• /
• 2021

In this study, joint analysis was conducted on the rock slope by aerial surveying using UAV. Aerial photos were taken using UAV to measure the directionality of the rock slope exposed to the site, and the directionality of the joint was analyzed using the photographed photos. UAV photography was taken under conditions of 90% overlap and an altitude of 50m. The photographing path was measured in the horizontal, vertical, and oblique directions based on the slope, and the joint characteristics were analyzed. Aerial surveying research on the joint directionality analysis of rock slopes is still incomplete, and the method for accurate joint directionality analysis is not presented strategically, so it is difficult to apply it in design. Through the results of this study, we would like to propose an flight photographing technique for the investigation of rock joints. As a result of the study, in the case of the joint investigation of the rock slope using UAV, it was necessary to change conditions such as altitude, aerial photography route, and overlap according to the size of the joint according to the site conditions.

• 한국항공운항학회:학술대회논문집
• /
• 2016.05a
• /
• pp.264-268
• /
• 2016

항공산업의 초창기에는 항공기 안전사고의 대부분이 기술결함으로 인하여 발생하였다. 그러나 항공기술의 발달로 인한 첨단화, 정밀화되면서 기술결함에 의한 사고는 대폭 감소하였지만 인적요인에 의한 사고는 일정한 수준 감소 이후 꾸준하게 유지하고 있다. ICAO따르면 인적요인의 70~80%가 재발 가능성이 존재하며 독자적인 원인이 아닌 위험요소의 복합적작용으로 발생한다고 기술하고 있다. 이를 방지하기 ICAO에서는 항공안전을 위협하는 사고(ACCIDENTS), 준사고(Serious INCIDENTS), 항공안전장애(HINDRANCES)등의 데이터를 수집, 공유, 분석을 통해 항공안전 위해요소를 사전에 제거, 차단할 수 있는 사전예방 시스템의 수립을 권고하고 있으며 이를 위해 국제사회를 중심으로 의무보고제도, 자율보고제도 등이 활발하게 운영되고 있다. 그러나 국내의 경우 운영시스템의 체계화 및 정부, 관련부처의 노력에도 불구하고 일부보고제도만이 정착되어있고 자율보고제도는 사회적 환경, 문화적 요건의 차이 등으로 인하여 활발하게 운영되지 못하고 있다. 따라서 국내 외 안전자율보고제도의 동향을 바탕으로 해당제도의 효율적인 정착 방안을 모색할 필요가 있을 것이다.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.34 no.4
• /
• pp.43-56
• /
• 2009

In korean peninsular, aircraft defense with SAM (Surface-to-Air Missile) is very important because of short range of combat space in depth. Effective and successful defense operation largely depends on two factors, SAM's location and the number of SAM for each target based on missile's availability in each SAM's location. However, most previous papers have handled only the former. In this paper, we developed Set covering model which can handle both factors simultaneously and Multi-heuristic algorithm for solving allocation problem of the batteries and missile assignment problem in each battery. Genetic algorithm is used to decide optimal location of the batteries. To determine the number of SAM, a heuristic algorithm is applied for solving missile assignment problem. If the proposed model is applied to allocation of SAM, it will improve the effectiveness of air defense operations.

• Proceedings of KOSOMES biannual meeting
• /
• 2005.11a
• /
• pp.85-90
• /
• 2005

이 연구에서는 대형위그선 개발에 따른 운항요원의 양성 방향에 관한 기초 연구를 수행하였다. 국제해사기구(IMO)는 2002년 12월 제76차 해사안전위원회에서 기존의 선박과 동일한 위그선의 충돌 회피규정 등 안전운항에 관한 잠정적인 가이드라인을 제정하였고, 지난 2005년 5월에는 위그선 운항요원의 운항지식, 운항기술 및 교육훈련 사항 등에 대한 가이드라인을 제시하였다. 위그선은 선박과 항공기의 복합형태인 새로운 운송수단임을 고려한 양성 교육과정 준비가 필요하다. 우리나라는 세계 최고의 조선 인프라와 기술력을 확보하여 대형위그선 건조는 기술적으로 실현가능할 뿐만 아니라 차세대 해상 수송혁신을 주도할 수 있다고 한다. 또한 최근 적재량 100톤급 대형위그선 실용화 사업이 해양수산부를 중심으로 순조롭게 추진되고 있다. 따라서 양 해양대학은 대형위그선 개발 시점에 맞춰 운항요원 양성을 통한 신규분야에 대한 블루오션 창출이라는 목표를 갖고 종합적인 연구와 체계적인 준비가 절실히 요구된다.