• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.1
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• pp.119-129
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• 2023

In many cases, trauma is overcome in a short periodtime, but for some, trauma results in long-term mental health issues such as in the form of post-traumatic stress disorder (PTSD). Natural disasters cause different types and extent of damage, meaning the degree of stress experienced also varies. In the case of damage to a house, the impact can be considerable. Therefore, this study examined the trauma experienced by households whose homes were damaged by natural disasters and to confirm the characteristics of psychological trauma. It was confirmed that traumas was greater when a house was damaged, compared with damage to other types of items. In addition, even in the case of trauma occurring, factors that affect the pattern of change to someone's mental state vary depending on the state's classification. And In addition, health services is significantly analyzed in all variables, and it was considered that the provision of basic services related to safety after a disaster is paramount. However, while psychological counseling has a positive effect on short-term traumas that manifests as anxiety and depression, it has an adverse effect on PTSD because of the depth and complexity of the suffering in PTSD, meaning the type of psychological support needs changing.

• Journal of the Korea Convergence Society
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• v.9 no.7
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• pp.9-16
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• 2018

The purpose of this study is to prevent the malicious user from breaking the door-lock due to physical impact. If it matches the analog displacement value set in the door-lock system, it protects the body and property by transmitting damage information in real time to the manager smart phone. The research suggests a system that transmits damage information in real time to registered users when door-lock is damaged by physical impact. Then compare the impact information sensed by the door lock with the data of the sensitivity control unit. In the web server of the proposed system, after impact information transmitted from Door-Lock is stored in the DB, if the impact information is larger than the shock detection transmission reference value stored in the DB, it is transmitted to the administrator in real time by SMS module so that illegal access information.

• Composites Research
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• v.22 no.2
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• pp.18-23
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• 2009

Failure of Kevlar29/Phenolic composite plate under high velocity impact of FSP(Fragment Simulation Projectile) is investigated using a non-linear explicit finite element code, LS-DYNA. Composite laminate and impactor are idealized by solid element and interface between laminas are modeled by tied-break element in LS-DYNA. Interaction between impactor and laminate is simulated face-to-face eroding contact algorithm. When the stress level meets a failure criteria, the layer in the element is eroded. Numerical results are verified by existing test results.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.645-648
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• 2008

The expansion joint is an important part of the bridge, but the failure is occurred on the non-shrinkage concrete which is connected to the slab of the bridge and the expansion joint, and the other problem is the release of anchors in expansion joint due to the impact and vibration during the driven car on the bridge, especially an overloaded car. In this study, to overcome the failure of non-shrinkage of concrete, high impact resisting mortar is developed. The high impact resisting mortar shall be a polyurethane material compounded with an aggregate system to develop excellent flexibility characteristics, high load bearing capacity.

• Journal of the Korean Society for Railway
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• v.15 no.3
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• pp.217-223
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• 2012

This study describes an experimental investigation about the impact damage characteristics of various types of high speed train window glass. Kinds of impact test standards for glass were studied and impact test considering scattering ballast were developed. Windows with external impact side made with annealed, heat strengthened and tempered glasses are likely to be broken by sharp tipped falling object. Broken shape of annealed glass is like line in part and that of heat strengthened glass is line on the whole. Tempered glass is destroyed to pieces. The change of tip type from sharp to blunt makes the higher destroyed level. Tempered glass has higher strength than annealed glass with blunt tip. When the protective films are attached to glasses, strength against destruction increases. In case of real ballast test, glasses without protective films were destroyed, but those with protective films are hard to be broken.

• Composites Research
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• v.29 no.6
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• pp.321-327
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• 2016

In this study, tests and finite element analyses were performed regarding compression after impact strength for laminated composite structures of unidirectional carbon fiber reinforced plastic widely used in structural materials. Two lay-up sequences of composite laminates were selected as test specimens and four impact energy conditions were applied respectively. Impact and compressive strength tests were conducted in accordance with ASTM standards. Impact damages in test specimens were analyzed by using non-destructive inspection method of C-Scan, and compression after impact strengths were calculated with compressive test results. Progressive failure analysis method that can progressively simulate damages and fractures of fiber/matrix/lamina/laminate level was used for impact and compressive strength analyses. All analysis results including contact force, deflection, impact damages, compressive strengths, etc. were compared to test results, and the validity of analysis method was verified.

• Nuclear Engineering and Technology
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• v.27 no.6
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• pp.932-937
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• 1995

1990년 12월 카나다의 Darlington 2호기에서 발생한 핵연료 다발의 양쪽 지지판에 있는 지지 금속판의 파손은 펌프 날개 통과 압력 충격파가 Acoustic 성격으로 중폭되어 연료봉지지판의 파손을 일으킨 것으로 추정되었고 이에 따른 주열수송계통에 대한 ABAQUS를 이용한 Acoustic 해석과 수많은 실험을 거쳐 Acoustic 압력 충격파가 핵연료 다발의 연료봉 지지판 파손 원인임이 입증되었다. 이러한 Acoustic 해석과 실험의 결과로써 Darlington 발전소의 열수송 펌프를 5 날개 펌프에서 7 날개 펌프로 교체시키게 되었으며 그 결과 핵연료 스트링의 축방향 진동을 감소시켜 연료봉 지지판의 파손을 방지하게 되었다. 이러한 사례로 인하여 최근 CANDU형 원자로 열수송 계통의 Acoustic 해석에 대한 연구가 AECL의 Chalk River Laboratory와 COG(CANDU Owners Group)에서 활발하게 진행되고 있다. 이 기고문에서는 매우 새로운 분야로써 현재 이루어지고 있는 CANDU형 원자로 열수송 계통의 Acoustic 해석을 위한 해석 이론과 해석 방법을 간단히 요약 정리하였다.

• Composites Research
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• v.35 no.6
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• pp.469-476
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• 2022

In this paper, the microwave absorbing characteristics after the impact of the radar-absorbing structure (RAS) consisting of periodic pattern sheet (PPS) and glass fiber-reinforced plastic (GFRP) were experimentally investigated. The fabricated RAS effectively absorbed the microwave in the X-band (8.2-12.4 GHz). In order to induce the damage to the RAS, a low-velocity impact test with various impact energy of 15, 40, and 60 J was conducted. Afterward, the impact damage was observed by using visual inspection, non-destructive test, and image processing method. Moreover, the absorbing performance of intact and damaged RAS was measured by the free-space measurement system. The experiment results revealed that the delamination damage from the impact energy of 15 J did not considerably affect the microwave absorbing performance of the RAS. However, fiber breakage and penetration damage with a relatively large damaged area were occuured when the impact energy was increased up to 40 J and 60 J, and these failures significantly degraded the microwave absorbing characteristics of the RAS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.648-655
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• 2020

The firing pin of modern automatic rifles detonates the primer of loaded ammunition via a hammer. During this process, the firing pin receives an impact load and repetitive force throughout the life of the rifle. An endurance test of a rifle showed that the firing pin breaks prematurely at 96.26% of life. Accordingly, a case study was conducted through cause analysis and a reconstruction test. Optical microscopy and scanning electron microscopy of the broken surface of the firing pin showed that a crack began in the circumferential direction of the surface, resulting in a fatigue crack to the core after repeated impact. Crack growth and fatigue destruction occurred at the end due to the repetitive impact and was estimated using a notch. For verification, a sample that produced a 0.03mm circumferential notch was broken at 64.25% of life in the reconstruction test. A test of breakage according to the notch types showed that a 0.3mm and a 0.5mm one-side notch were broken at 66.53% and 50.76%, respectively, and a 0.03mm six-point notch was broken at 85.65%. The endurance life of a sample firing pin with a rough surface and tool mark was examined, but an approximately 381 ㎛ internal crack formed. Through this study, failure for each notch type was considered. These results show that quality control of the notch and surface roughness is essential for ensuring the reliability of a component subjected to repeated impact.

• 환경사랑
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• s.67
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• pp.10-10
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• 2013

명절 등에 배달되는 농산물 가운데 택배업자들이 외부 충격에 약한 과일 등 농산물의 특성을 고려하지 않고, 일반 공산품처럼 아무렇게나 취급하기 때문에 상품이 파손 되는 경우가 늘고 있다. 산지에선 멀쩡했던 농산물이라도 택배 등 물류과정을 거쳐 소비자에게 도착했을 땐 품질이 크게 망가져 있는 사례가 적지 않다는 것이다. 이러한 불편을 해소하기 위한 충격흡수용 과일 상자가 개발되어 사용되고 있다고 "농민신물"이 보도(2. 27. 10면)했다. 관련 기사를 발췌하여 소개한다.