• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.11a
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• pp.19-19
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• 2004

• Journal of the Korean Society of Safety
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• v.24 no.5
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• pp.43-47
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• 2009

Armor block is used to reduce wave energy. To do this, the stability of coastal structure is enhanced. It is very expensive to develop a new type armor block. So, the research of new type armor block is very short. We develope truncated tetrahedron type armor block(new type block) which have a hole in center part. In this study, the stability of new type armor block is investigated by hydraulic model test. In the result, the stability coefficient($K_D$) of new type armor block is 11.8. this value is more superior than value of tetrapod.

• International Journal of Human Ecology
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• v.13 no.1
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• pp.117-128
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• 2012

This study compares the net effect of wearing different shoulder/arm armor systems on garment impediment perception and wearer acceptability. Two independent variables in this study were armor systems and shoulder/ arm movements. There were four armor systems of control garment and arm armor systems A, B, and C as well as five types of arm/shoulder movements, (shoulder flexion, should extension, shoulder abduction, shoulder horizontal flexion, and shoulder horizontal extension). Ten male volunteers wearing size medium battle dress uniform (BDU) with recent relevant military experience participated in this study. The volunteers performed shoulder/arm movements (while wearing each armor treatments) and completed the garment impediment perception as well as wearer acceptability scales. The body areas of neck side, shoulder top, and armscye front showed the highest frequency of reported impediments. Resistance to movement and localized pressure were the most frequently mentioned types of impediment. The armor system B had the most areas of impediment, and was rated as more restrictive than the control garment and armor system A for each movement. For wearer acceptability, no significant differences were found between the control garment and armor system A for all eight items; this indicated that subjects did not perceive a difference between wearing the control garment and armor system A. There was a trend for wearer acceptability to decrease from wearing the control garment to armor systems A to C to B.

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.521-529
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• 2019

Interlocked armor layers of unbonded flexible risers may crush when risers are being launched. In order to predict the behavior of interlocked armor layers, they are usually simplified as rings with geometric and contact nonlinearity ignored in the open-literature. However, the equivalent thickness of the interlocked armor layer has not been addressed yet. In the present paper, a geometric coefficient ${\gamma}$ is introduced to the equivalent stiffness method, and a linear relationship between ${\gamma}$ and geometric parameters of interlocked armor layers is validated by analytical and finite element models. Radial stiffness and equivalent thickness of interlocked armor layers are compared with experiments and different equivalent methods, which show that the present method has a higher accuracy. Furthermore, hoop stress distribution of interlocked armor layer under crushing is predicted, which indicates the interlocked armor layer can be divided into two compression and two expansion zones by four symmetrically distributed singular points.

• Journal of the Korean Society of Mechanical Technology
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• v.20 no.6
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• pp.879-885
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• 2018

Precedent research and development of personal armor and anti-stab wearing system has been conducted since 2018 as a part of the government-affiliated cooperative development project to create the best utilization of present technology and achievement according to the civil and military technical cooperation project promotion law. At present, the armor system operated by the ROK(Republic of Korea) military, the police, and the marine police is utilizing only basic armor using armor vests and plates. Therefore it is necessary to develop the personal armor and anti-stab wearing system which is suitable for various tasks in army with maximum protection capability. In this paper, we analyzed the study about international technologies, market trends of the developed countries and scope of research, utilization plan, R&D results for the best armor and anti-stab wearing system development.

• Conservation Science in Museum
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• v.26
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• pp.35-66
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• 2021

This study conducted scientific analysis and conservation treatment on four suits of armor and two helmets from the collection of the National Museum of Korea. Based on the findings, it identified structural characteristics of armor from the middle and late Joseon Dynasty. Since a suit of armor is made of composite materials consisting of both organic and inorganic elements, conservation treatment was conducted to the extent that the stable condition of each material remained unaffected by the other materials. The process took place in the sequence of investigation and analysis, removal of contamination, stabilization and reinforcement, repair of damaged parts, and storage. The armor and helmets had suffered severe damage, but were safely repaired and partially restored through the conservation treatment. The findings from the conservation treatment revealed the materials used and structural characteristics of the armored skirt from a two-piece set of armor from the middle Joseon period and for the two suits of overcoat-style armor, suit of vest-style armor, and helmets from the late Joseon era. It also allowed the investigation of the production methods of the armor and helmets.

• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.47-55
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• 2016

This study is on the stability re-evaluation of armor stones in saemangum seadike according to recently increased sea-level and frequent high wave incoming and the results are in the following. The field inspection of armor stones in the seadike revealed that damages of armor stones have been caused by higher waves than designed waves and that the reconstruction of armor stones and concrete grouting method have been used as the reinforcement work. The result of numerical simulation of wave channel conducted to estimate the safety weight of armor stones influenced by flows revealed that the safety weight of armor stones in the seadike No.4 was estimated as 5.47 tons by using the Isbash method, which is about 122 % more than 4.49 tons estimated by using Van der Meer method. Therefore, in designing armor stones which can be influenced by high waves such as the case of Saemangum seadike, it is necessary to apply the safety weight method of armor stones, based on the Isbash method, which produced the significant figures among the safety weight methods using flows as well as the safety weight method using high waves based on the Hudson method.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.5
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• pp.19-27
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• 2015

The results of Saemangeum seadike field inspection and material testing of armor stones in order to analyze causes of abrasion according to material characteristics of seaside armor stones in Saemangeum seadike are in the following: 1. The armor stones in Saemangeum seadike have been constructed by using internal stones (mainly, sinsi stones) and external stones, which had less strength (77.3 %) and more abrasion rate (133.3 %) compared with sinsi stones. 2. The compressive strength and abrasion rate were compared between ordinary wave section and high wave section for the purpose of analyzing the influence of waves. In compressive strength, sinsi stones were 4.0 % stronger and external stones were 0.6 % stronger in ordinary wave section than those of high wave section in average. In the case of abrasion rate, sinsi stones were 3.0 % higher and external stones were 8.2 % higher in the high wave section than those in the ordinary section. 3. The result of comparing compressive strength according to a zone is that the compressive strength in the Intertidal area was less strong in most of the zones. 4. Considering that deviated stones are moving around over the surface of armor stones in situ, it is important to compare material characteristics. So the comparison test about this factor showed that deviated sinsi stones were stronger than armor stones in situ in terms of compressive strength and resistance to abrasion. Based on these results, abraded armor stones may have resulted from their durability. Therefore it is assumed that armor stones are likely to be abraded when deviated stones which are more durable are moving around over armor stones which are less durable.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.187-196
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• 2013

This study is focused on analyzing the deformation types of seaside armor stones based of field survey in order to establish the cause of abrasion following the deformation of seaside armor stones. 1. The deformation of seaside armor stone in saemangeum sea dike was classified as three different types: floating, deviation, and abrasion. 2. It was discovered that the stones floated to the extent of maximum 50 m, as the result of inspecting floating stones which were situated on different ten places. 3. The average number of deviation in the high ocean wave section was four times more than that in the ordinary ocean wave section, as a result of comparing the deviation number of the ordinary ocean wave section and that of the high ocean wave section for the purpose of inspecting the relation between the deviation of armor stones and the effects of ocean wave. 4. The angular shape of armor stones seen in the initial construction period has been abraded smoothly, as result of comparing of the shape change of armor stones for the purpose of inspecting abrasion state of seaside armor stones. 5. It was discovered that the abrasion of armor stone was severe in the section of many floating stones, as a result of analyzing the levels of abrasion and the cumulative sections of floating stones for the purpose of investigating the cause of abrasion.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.3
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• pp.131-138
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• 2021

The armor blocks are used to protect the body of the structure and dissipate wave energies, so it is crucial to evaluate the stability of the armor unit. The stability of armor blocks has been mainly evaluated through empirical coefficients called the stability coefficient obtained from hydraulic model experiments. In this study, a new type of single-layered armor block called K-Block was proposed, and a new experimental method based on the pull-out force was proposed to evaluate the stability of the armor unit, including the interlocking effects. The pull-out force test proposed in this study directly measures the force required to separate the armor unit from the armored layer on the slope by applying a tensile force in the vertical and horizontal directions to the installed armor unit. The proposed experimental method confirmed that the interlocking effects of the armor block could be quantitatively evaluated, and the high stability of the K-Block was verified.