• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.12
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• pp.1229-1235
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• 2008

ELT(emergency locator transmitter) has assisted in the rescue of thousands of lives in distress. Aviators, mariners and land users being equipped with distress beacons are capable of transmitting distress signals to the satellites in emergency situations anywhere in the world. In this paper, Drop/Impact simulation was performed for ELT Body-case. FE model for Body-case was constructed with MSC/Dytran and refined using the Karas example simulation for Body-case prototype. Shock/impact survivability analysis was performed for ELT operations. FE model constructed with MSC/Nastran. Transient response analysis for refined ELT model was perfomed for ELT under impact shock loading condition.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.6
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• pp.322-330
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• 2020

This study deals with underwater explosion (UNDEX) characteristics of various non-explosive underwater shock sources for the development of non-explosive underwater shock testing devices. UNDEX can neutralize ships' structure and the equipment onboard causing serious damage to combat and survivability. The shock proof performance of naval ships has been for a long time studied through simulations, but full-scale Live Fire Test and Evaluation (LFT&E) using real explosives have been limited due to the high risk and cost. For this reason, many researches have been tried to develop full scale ship shock tests without using actual explosives. In this study, experiments were conducted to find the characteristics of the underwater shock waves from actual explosive and non-explosive shock sources such as the airbag inflators and Vaporizing Foil Actuator (VFA). In order to derive the empirical equation for the maximum pressure value of the underwater shock wave generated by the non-explosive impact source, repeated experiments were conducted according to the number and distance. In addition, a Shock Response Spectrum (SRS) technique, which is a frequency-based function, was used to compare the response of floating bodies generated by underwater shock waves from each explosion source. In order to compare the magnitude of the underwater shock waves generated by each explosion source, Keel Shock Factor (KSF), which is a measure for estimating the amount of shock experienced by a naval ship from an underwater explosionan, was used.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.33 no.4
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• pp.255-261
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• 2020

This study proposes a method of constructing an effective shock absorber. The existing shock absorber is fabricated only with polyethylene; however, the new shock absorber comprises polyethylene on the outside and a high-density material on the inside. The shock was mostly reduced when the density difference between the inner and outer materials was large. Aluminum, titanium, and copper were chosen as the outer structure of two-layer. Shock reduction was most effective in copper with the highest density, and the maximum deceleration was reduced by 43% while the impulse was reduced by 51% in the proposed shock absorber than the traditional shock absorber. In the cases of four-layer and six-layer shock absorbers, the impulse was reduced, but the maximum deceleration was increased. The fuze must survive from the biggest shock and the remaining shock waves should not exceed the threshold. Thus, a two-layer structure shock absorber using polyethylene-copper was proposed.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.222-229
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• 2024

As the operating condition for the penetrating missile has been more advanced, the survivability of main charge has been strongly required when the warhead impacts the target. Lots of efforts to desensitize explosives such as the development of insensitive molecular explosives or optimizing plastic-bonded explosives(PBX) systems has been made to enhance the survivability of main charge. However, these efforts face their limits as the weapon system require higher performance. Herein, we suggest a new strategy to secure the survivability of main charge. We applied structurally supportable aluminum honeycomb(HC) structure to cast PBX. The aluminum HC structure reinforces the mechanical strength of cast PBX and helps it to withstand external pressure without the reaction like detonation. In this study, impact resistance character, shock sensitivity and internal blast performance of PBXs reinforced with HC structure were investigated according to the application of aluminum HC structure. The newly suggested aluminum HC structure applied to cast PBX was proved to be a promising manufacturing method available for high-tech weapon systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.129-132
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• 2010

The objective of IM rocket motor is to minimize the probability of inadvertent initiation and severity of subsequent collateral damage, hence it is important to define personnel and equipment survivability to a rocket motor accident. The violent response probability associated with shock, impact and thermal effects be minimized. And during production, transportation/storage and stack of rocket motor, sympathetic detonation, giving severe effects of the propagation of adverse reaction on its surroundings, be reduced. Hence Reaction type also based on reaction results of the overpressure, fragment throw and heat flux.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.601-607
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• 2012

The main function of a landing gear is to absorb the impact energy during touchdown. It it occasionally required for landing gear to have crashworthiness for improving survivability and safety in case of emergency landing. This paper introduces the design concept, performance analysis and drop test procedures for the development of the crashworthy landing gear. The shock absorbing ability and the crash behavior are proved by analyzing various sensor data and video clips from high speed camera recording during drop tests.