• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.194-199
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• 2003

Developed m this research is a production information system for marie propellers. The paper deals with surface modeling and tool path generation modules of the system. Since the input point data may have some errors, the data is examined using the 2nd divided difference. The point data is interpolated to a $G^2$ chord-length spline surface with some end-conditions. The effects of the various end-conditions on the interpolated surface are discussed in the paper. The tool paths for blade, fillet, and boss of the propeller are generated. Some illustrative examples from an industry are presented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.4
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• pp.1-8
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• 2020

Mechanical components that support structures in aerospace and power generation industries require high-strength materials. Particularly, in the aerospace industry, aluminum alloys, titanium alloys, and composite materials are increasingly used due to their high maneuverability and durability to withstand low temperature extreme environments; however, ultra-high-strength steel is still used in key components under heavy loads such as landing gears. In this paper, the fault cause analysis and troubleshooting of aircraft parts made of ultra-high-strength steel (300M) broken during normal operation are described. To identify the cause of the defect, a temporary inspection of the same aircraft was performed, and material testing, non-destructive inspection, microstructure examination, and fracture area inspection of the damaged parts were performed. Fracture analysis results showed that a crack in the shape of a branch developed from the tool mark in the direction of the intergranular strain. Based on the results, the cause of fracture was confirmed to be stress corrosion.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.2
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• pp.179-186
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• 2012

The potential hazards resulting from a low-velocity impact(bird-strike, tool drop, runway debris, etc.) on aircraft structures, such as engine nacelle or leading edges has been a long-term concern to the aircraft industry. Certification authorities require that exposed aircraft components must be tested to prove their capability to withstand low-velocity impact without suffering critical damage. In most of the past research studies unloaded specimens have been used for impact tests, however, in reality it is much more likely that a composite structure is exposed to a certain stress state when it is being impacted, which can have a significant effect on the impact performance. And the radiated impact sound induced by impact is analyzed for the damage detection evaluation. In this study, an investigation was undertaken to evaluate the effect in-plane loading on the impact force and sound of composite laminates numerically.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.27-33
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• 2019

The aviation industry has grown beyond the simple processing and assembling of aircraft parts and now designs and exports finished aircraft. In this study, the vertical CNC milling rotational speed and feed rate were parameters to investigate the life of tools according to their shape: (flat, round, and ball end mill) in the rough cutting of titanium. These tools are widely used in aircraft manufacturing and assembly. The purpose of this study is to measure the cutting temperature generated during the cutting process and calculate the rate of tool wear. This will be accomplished by measuring the tool weight before and after cutting the specimen and to compare it with the results of previous studies. Our study showed that the maximum cutting temperature increased as cutting time, tool rotational speed, and feed rate increased. The highest cutting temperatures were recorded for the ball, round, and flat end mill, respectively. Tool wear for the ball, round, and flat end mill increased as the speed and feed rate increased. The flat end mill exhibited the highest rate of wear from a minimum of 0.62% to a maximum of 2.88%.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.3
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• pp.44-51
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• 2021

PIP is an abbreviation of 'Performance Improvement Package', which is a package that can improve performance by applying some design changes to existing aircraft. Boeing provides PIP applicable to B777-200, and Airbus provides PIP applicable to A350-900 as standard. PIP provided by Boeing and Airbus is a separate task, but it is expected to reduce fuel consumption by reducing drag through aerodynamic improvements. The PIP applied to the A350-900 includes work such as increasing Winglet Height and re-twisting Outboard Wing. This study is to verify the effect of PIP application of the A350-900 aircraft and use it as basic data for economic analysis. The aerodynamic improvement studies and expected effects of the PIP application were examined, and the actual flight data of the PIP-applied and the non-applied aircraft were compared to confirm the PIP application effect. This paper provides empirical results for the aviation industry on the PIP application efficiency as a method of improving fuel efficiency and reducing carbon emission.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.4
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• pp.134-141
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• 2021

As the domestic aviation industry grows, the aviation maintenance field is also growing rapidly. This change calls for more aircraft maintenance technicians, and interest in safety accidents is also increasing. Individual safety climate indicates the importance of safety in the organization. We expect that three individual factors (training effectiveness, procedure effectiveness, and work pressure) relate to safety behavior in the workplace via individual safety climate. The purpose of this research is investigating the relationship between individual factors and aircraft maintenance technician's safety behavior. Previous studies related to individual factors were examined for literature review. Based on the previous studies, research model was constructed. Hypothesis was verified by effected data from 305 samples were employed for final survey. The results show that individual factors were meaningful factors to effect perceived safety behavior, and safety knowledge & safety motivation were related to safety compliance & safety participation.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.2
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• pp.135-141
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• 2024

Despite the innovative technological advances in the aviation industry, hard landing events that occur during aircraft landing account for 13% of all accidents. Hard landing when landing an aircraft affects normal operation by generating a large load on the landing gear and the fuselage. In order to identify these risk factors, the airline monitors the high vertical acceleration event, a precursor to hard landing, through QAR (Quick Access Recorder) flight data analysis, and prepares and implements mitigation measures. In this study, it is intended to contribute to safety management based on flight data analysis that identifies the characteristics of high vertical acceleration G event data that can cause such hard landing and detailed parameters of precursor signs, and to identify the causal relationship of the occurrence of the event by applying statistical analysis methods such as variance analysis, correlation analysis, and regression analysis models to identify the characteristics of the event occurrence and eliminate the cause in advance.

• Journal of the Korean Society for Nondestructive Testing
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• v.21 no.2
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• pp.177-181
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• 2001

Nondestructive testing(NDT) is one of the fundamental tools to improve the quality of commercial and industrial products. NDT is potentially a major application of interferometry. Interferometry(ESPI, Shearography, ect) has successfully been applied in various industrial environments such as high performance aircraft, home appliance, automotive, and laminates on engine structures, etc. Today's industry demands high performance components with toughest mechanical features and ultimate safety standards. Especially in automotive and aircraft industry the development process focuses on tailor-made design and solutions to meet customer specifications. To reconcile economy, ligh-weight construction has become a key issue. Many companies are looking for new advanced NDT techniques to archive cost efficiency over the limitations of classical methods. ESPI and shearography allow a rapid, full field and 3D-measurement without contact. In this paper recent applications of ESPI and shearography for NDT are described. Advanced features of classical techniques are specified and new applications in material and component testing are presented.

• The Journal of Aerospace Industry
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• s.65
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• pp.70-88
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• 2003

필자가 참여했던 쌍발복합재사업, 쌍발복합재항공기사업, SB427 민수용헬기사업, T-50 초음속고등훈력기 사업을 통해 복합재료의 항공기 적용사례를 고찰하면서, 쌍발복합재항공기는 실험용항공기(Experimental Aircraft)이지만 국내 최초의 전복합재항공기(All-composites Aircraft)로서 항공기 구조물이 순전히 복합재료만을 이용하여 설계 및 제작이 가능하다는 것을 보여주었고, 복합재료를 적용 시 어떠한 이점이 있는지를 보여준 예가 되고 있다. SB427 민수용헬기사업은 헬리콥터에서 로터 블레이드와 동체 등 기체구조물 대분에 왜 복합재료를 사용해야 효과적인 지를 잘 보여주고 있다. SB427 개발 사업을 통해 얻을 수 있는 또 다른 점은 민수용 항공기의 경우 구축된 복합재료 인증체계에 따라 복합재구조물을 개발해야 되고 그래야만 마케팅에서 신뢰를 얻을 수 있다는 것이다. T-50 항공기는 국내에서 최초로 개발된 초음속기로 미익 부문에 복합재료가 응용되었다. 양산 항공기의 주구조물에 복합재료가 쓰인 예는 T-50이 첫 번째 인데 T-50에서 얻어진 복합재 적용기술은 앞으로 개발될 고급 군용기와 민수용기에 널리 활용될 것으로 기대된다. 본 논문에서는, 국내 개발 항공기에서의 복합재료 적용이라는 특정 주제를 중심으로 개발 이력과 기술적 조망을 통하여, 정부, 연구소, 업체 간의 유기적이고 체계적인 전략이 필요하다고 사료되며, 이러한 전략을 바탕으로 효율적인 항공 산업을 선점해야 할 것이다.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1127-1133
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• 2022

Recently, the use of aircraft structures using Ti alloy (Ti-6Al-4V), a lightweight high-strength alloy material, is rapidly increasing due to the weight reduction of aircraft. However, high-strength materials such as Ti alloys require high energy for cutting and are classified as difficult-to-cut materials. Also, research on Laser Assisted Machining (hereinafter referred to as LAM), a cutting processing technology that utilizes improved machinability, is being actively researched. Therefore, in this paper, in order to confirm the proper temperature distribution using a laser, the finite element method is used to determine the temperature distribution according to the calorific value condition to derive the appropriate condition, and the thermal load generated at this time is used as a structural analysis. It is intended to be used as basic data for LAM processing conditions by measuring the amount of residual stress and thermal deformation caused by heat.