• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.3
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• pp.97-109
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• 2005

A canard type aircraft, which has good wing stall and stall/spin-proof characteristics, is under development. The aircraft prototype has full-depth core sandwich type wing and fixed landing gear, and has been built for test flights. Newly developing aircraft will be equipped with retractable landing gear and conventional foam core sandwich laminate structures and multi-rib wings. In this study, we present the structural test procedure and result for aircraft Firefly.

• Advances in materials Research
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• v.5 no.1
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• pp.11-20
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• 2016

In bonded composite repair of aircraft structures, the damage of the adhesive can thus reduce significantly the efficiency and the durability of the bonded composite repair. The adhesive damage models using critical zone have proven their effectiveness due to simplicity and ap-plicability of the damage criteria in these models. The scope of this study is to analyze the effects of the patch thickness and the adhesive thickness on the damage damage in bonded composite repair of aircraft structures by using modified damage zone theory. The obtained results show that, when the thickness of adhesive increases the damage zone increases and the adhesive loses its rigidity, inversely when the patch is reduced the adhesive damage be-comes more significant.

• Nuclear Engineering and Technology
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• v.52 no.2
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• pp.397-416
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• 2020

Investigations of the commercial aircraft impact effect on nuclear island infrastructures have been drawing extensive attention, and this paper aims to perform the safety assessment of Generation III nuclear power plant (NPP) buildings subjected to typical commercial aircrafts crash. At present Part II, based on the verified finite element (FE) models of aircrafts Airbus A320 and A380, as well as the NPP containment and auxiliary buildings in Part I of this paper, the whole collision process is reproduced numerically by adopting the coupled missile-target interaction approach with the finite element code LS-DYNA. The impact induced damage of NPP plant under four impact locations of containment (cylinder, air intake, conical roof and PCS water tank) and two impact locations of auxiliary buildings (exterior wall and roof of spent fuel pool room) are evaluated. Furthermore, by considering the inner structures in the containment and raft foundation of NPP, the structural vibration analyses are conducted under two impact locations (middle height of cylinder, main control room in the auxiliary buildings). It indicates that, within the discussed scenarios, NPP structures can withstand the impact of both two aircrafts, while the functionality of internal equipment on higher floors will be affected to some extent under impact induced vibrations, and A380 aircraft will cause more serious structural damage and vibrations than A320 aircraft. The present work can provide helpful references to assess the safety of the structures and inner equipment of NPP plant under commercial aircraft impact.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.18-31
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• 2018

Rotorcrafts have more severe crashworthiness conditions than fixed wing aircraft owing to VTOL and hovering. Recently, with the increasing demand for highly efficient transportation system, application of composite materials to aircraft structures is increasing. However, due to the characteristics of composite materials that are susceptible to impact and crash, demand to prove the crashworthiness of composite structures is also increasing. The purpose of present study is to derive the structural concept of composite subfloor for rotorcrafts and verify it. In order to design a crashworthy composite subfloor, the conceptual design of the testbed helicopter for the demonstration and the derivation of energy absorbing requirement were carried out, and the composite energy absorber was designed and verified. Finally, the testbed for the demonstration of a crashworthy composite structure was fabricated, and performed free drop test. It was confirmed that the test results meet the criteria for ensuring occupant survivability.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.1
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• pp.117-124
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• 2010

The bird strike to small aircraft has not been an issue because of its low speed and usage as a private aircraft. So, the compliance of the bird strike regulation is limited to large fixed-wing aircraft such as the commuter category in FAR Part 23 and the civil aircraft in FAR Part 25, generally. However, the forecast of dramatic increasing of VLJ(Very Light Jet), the usage of a composite material for an aircraft structure and flight time of general aviation due to Air-taxi for the point to point transportation, would rise up the need of bird strike regulations and a safety enhancement in normal and utility categorized aircraft. In this study, the safety of bird strike to small aircraft wing leading edge made of a metal and a composite material were compared using the explicit finite element analysis.

• Journal of Korean Association for Spatial Structures
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• v.5 no.4 s.18
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• pp.7-14
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• 2005

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.3
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• pp.1-7
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• 2014

The base of leisure air activities are consistently expanding and its demand is expected to increase attributed to GDP growth and people's interest in its activity. Utilizing Visual Flight Rule, light sport aircrafts and ultra-light aircrafts are not under the effect of air traffic control center, which resulted in passenger injury due to emergency landing for adverse weather conditions and technical issues after pulling into mountain area, ocean and even urban area. Such events encouraged safety consciousness toward leisure aircraft activities and developing a measure to prevent a recurrence of the accident. This research focuses on suggesting compositive system for preventive safety management system by providing user based Flight information service and operating effective system, necessary for leisure aircraft activities.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.12
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• pp.1070-1079
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• 2012

The impact energy absorbing is a very important characteristic of an aircraft to enhance the survivability of occupants when an aircraft is under the survivable accident such as an emergency landing condition. The impact energy is generally transmitted into the occupant and absorbed through a landing gear, a subfloor (lower structure of fuselage), and a seat. The characteristic of crash energy absorbing of a subfloor depends on the type of an aircraft, a shape of structure, and an applied material. Therefore, the study of crashworthiness characteristics of a subfloor structure is very important work to improve the safety of an aircraft. In this study, a finite element model of a narrow body fuselage section for the 80~90 seats regional aircraft was developed and crash simulation was executed using an explicit finite element analysis. Through survey of the impact energy distribution of each structural part of a fuselage and floor-level acceleration response, the crashworthiness characteristics and performance was evaluated.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.1-7
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• 2017

The development of effective design allowable values for unmanned composite aircraft is an issue of paramount concern for the industry. The application of conventional manned aircraft structural certification methods to unmanned aircraft such as prototype and technology demonstrators, can lead to excessively long development time and costs. In this paper, the determining method of composite structure design allowable values for light composite unmanned aircraft is presented to reduce to the structural weight. This paper seeks to show the applicability of composite B-basis material values as a design allowable of light composite unmanned aircraft structures. A review of different civil and UAV targets failure probability is given. From the results, the researchers can know that the requirements of light composite unmanned aircraft design allowable should be alleviated, compared to manned composite aircrafts.

• Smart Structures and Systems
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• v.6 no.2
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• pp.147-165
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• 2010

Impact damage detection in composite structures has gained a considerable interest in many engineering areas. The capability to detect damage at the early stages reduces any risk of catastrophic failure. This paper compares two advanced signal processing methods for impact location in composite aircraft structures. The first method is based on a modified triangulation procedure and Genetic Algorithms whereas the second technique applies Artificial Neural Networks. A series of impacts is performed experimentally on a composite aircraft wing-box structure instrumented with low-profile, bonded piezoceramic sensors. The strain data are used for learning in the Neural Network approach. The triangulation procedure utilises the same data to establish impact velocities for various angles of strain wave propagation. The study demonstrates that both approaches are capable of good impact location estimates in this complex structure.