• Advances in Computational Design
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• 제4권3호
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• pp.295-305
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• 2019

The sealing cement of total hip arthroplasty is the most widely used binder in orthopedic surgery for anchoring implants to their recipient bones. Nevertheless, this latter remains a fragile material with weak mechanical properties. Inside this material cracks initiate from cavities. These cracks propagate under the effect of fatigue and lead to the failure of this binder and consequently the loosening of the prosthesis. In this context, this work consists to predict the position of cracks initiation and their propagations path using the Extended Finite Element Method (XFEM). The results show that cracks can only be initiated from a sharp edges of an ellipsoidal cavity which the ratio of the minor axis over the major axis is equal to 0.1. A maximum crack length of 19 ?m found for a cavity situated in the proximal zone position under a static loading. All cracks propagate in same(almost) way regardless of the cavity(site of initiation) position and its inclination in the proximal zone.

• 한국전기전자재료학회논문지
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• 제36권1호
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• pp.1-9
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• 2023

According to the recent global warming, it is necessary to use energy efficiently together with eco-friendly energy. The development of alternative technologies is requisite for managing the current energy and climate crises. In this regard, "smart windows," which can control solar radiation, can be used to mitigate energy demands. Electrochromic devices (ECDs) effectively control the amount of solar energy reaching commercial and other living areas and maintain climate conditions via color modulation in response to small external stimuli, such as temperature and light irradiation. However, the performance and the stability of ECDs depend on the state of the electrolyte and sealing of the device. To resolve the aforementioned issues, an ECD was manufactured by using a poly (methyl methacrylate) (PMMA)-based gel polymer electrolyte (GPE), and a laminating method was used to adequately seal the ECD. The concentrations of PMMA, acetonitrile (ACN), and ferrocene (Fc) were controlled to optimize the composition of the GPE to achieve an enhanced electrochromic performance. The fabricated GPE-based ECD afforded high optical contrast (~81.92%), with high electrochromic stability up to 10,000 cycles. Moreover, the lamination method employing the GPE could be used to fabricate large-area ECDs.

• 한국터널지하공간학회 논문집
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• 제21권2호
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• pp.301-321
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• 2019

본 논문에서는 강관다단 그라우팅에 적용하는 속경성 실링재 개발에 관한 실험적 내용을 다루었다. 강관다단 그라우팅 공법에서 실링재는 본 주입재의 주입시 역류를 방지하기 위해 주입하며 주입 후 일정시간이 지난 다음 겔화 상태에서 본 주입재를 주입해야 한다. 그러나 주입된 실링재가 겔 상태가 되기 이전 유동성이 있을 경우 본 주입재와 함께 혼합됨은 물론, 주입재의 역류가 발생되어 원지반으로 주입이 곤란하며, 반대로 너무 시간이 지나 겔화단계를 넘어 고결되었을 경우 본 주입재가 지반내로 주입되지 못하는 경우가 발생된다. 실링재의 유동성이 없어져 겔화 상태로까지 걸리는 시간에 따라 강관다단 그라우팅의 공사시간이 결정되며, 이는 전체 터널의 공사기간과 밀접한 관련이 있어 중요한 요소 중에 하나이다. 따라서 본 연구에서는 실링재 본연의 역할과 기능을 할 수 있을 뿐 아니라 공사기간을 단축시킬 수 있도록 실링재의 겔화시간을 단축시킬 수 있는 칼슘알루미네이트 재료를 개발하였고, 실링재 겔화 여부를 판단하는 방법에 대해 제시하고, 아울러 실링재의 겔 상태에서 블리딩율에 대해서도 각 품질기준과 시험방법에 대해 제안하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2000년도 제31회 춘계학술대회
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• pp.194-200
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• 2000

The sealing performance of an elastomeric O-ring seal using NBR and FFKM has been analyzed for the contact stress behaviors that develop between the O-ring seal and the surfaces with which it comes into contact. The leakage of an O-ring seal will occur when the pressure differential across the seal just exceeds the initial (or static) peak contact stress. The contact stress behaviors that develop in compressed O-rings, in common case of restrained geometry(grooved), are investigated using the finite element method. The analysis includes material hyperelasticity and axisymmetry. The computed FEM results show that the contact stress behaviors are related to materials of NBR and FFKM and temperature of vaccum chamber.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2005년도 춘계학술발표대회 논문집
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• pp.217-220
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• 2005

한국항공우주연구원과 신영중공업(주)는 L.T.A 비행체의 주구조물인 기낭(envelope)의 설계 및 제작을 국내 기술에 의해 개발하는데 성공하였다. 막재료를 고어로 재단하여 열접합으로 이어 붙여 제작하는 기낭의 개발에는 설계 및 제작에 기존의 항공기와는 구별되는 설계 및 제작기술이 요구된다. 본 연구에서는 개념설계 단계로부터 제작도면화 및 생산에 이르기 까지 전 공정을 국산화하는데 성공하였다. 본 논문에서는 이번 연구성과를 요약하였다.

• 한국기계가공학회지
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• 제19권9호
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• pp.33-39
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• 2020

Self-piercing rivets are often used in the automotive industry, among other industries, as mechanical components to join multiple materials such as aluminum alloys. Self-piercing rivets have a strong sealing property, although there is considerable scope for their performance improvement. In this study, to enhance the performance of self-piercing rivets, the hybrid self-piercing riveting (SPR) technique, using the existing SPR and structural adhesive, was proposed. Moreover, heterogeneous material specimens subjected to the hybrid SPR technique were manufactured and tested. The joint strength of the test pieces of different materials was evaluated through finite element analyses.

• 한국공작기계학회논문집
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• 제15권1호
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• pp.88-94
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• 2006

A typical disk brake system consists of caliper housing, piston, seal and two pads etc. The configuration of seal groove, dimension of piston and seal, and seal material properties are important ones for brake performance, as these affect the retraction of piston. The rubber seal is designed to perform dual functions of sealing the brake oil at brake-applied and retracting the caliper piston at brake-released. In this paper, the seal stress is analyzed using Finite Element Method and experiment is conducted by Taguchi's Method. We attempt to quantify the critical design factors in the seal groove and evaluate their impact on some of brake performance factors. The investigation obtained from this study can not only enhance the seal groove design optimization, but also reduce product prototype testing and development time.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.129-132
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• 2007

Advanced structure of metal-supported solid oxide fuel cells was devised to overcome sealing problem and mechanical instability in ceramic-supported solid oxide fuel cells. STS430 whose dimensions were 26mm diameter, 1mm thickness and 0.4mm channel width was used as metal support. Thin ceramic layer composed of anode(Ni/YSZ) and electrolyte(YSZ) was joined with STS430 metal support by using a cermet adhesive. $La_{0.8}Sr_{0.2}Co_{0.4}Mn_{0.6}O_{3}$ perovskite oxide was used as cathode material. It was noted that oxygen reduction reaction of cathode governed the overall cell performance from oxygen partial pressure dependance.

• Tribology and Lubricants
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• 제16권2호
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• pp.138-143
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• 2000

The sealing performance of an elastomeric O-ring seal with a temperature gradient has been analyzed for the contact stress behaviors that develop between the O-ring seal and the housing surfaces with which it comes into contact in the dovetail groove. The leakage of an O-ring seal will occur when the pressure differential across the seal just exceeds the initial peak contact stress. The contact stress behaviors that develop in compressed O-rings, in common case of restrained geometry (grooved), are investigated using the finite element method. The FE analysis includes material hyperelasticity and axisymmetry The computed FEM results show that the contact stress behaviors are related to a compression rate and a temperature gradient between the vacuum chamber with a dovetail groove and the contacting plate with a cooling jacket.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.391-394
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• 2003

It is inevitable that reconsideration of the use of lead oxides in the electronics industry be undertaken as long as detrimental effects to the environment remain. To solve this problem, many recent studies on Pb-free compositions for PDP (plasma display panel) dielectric layers and also sealing glass compositions have been made. The present study was conducted to investigate whether the alternative systems for leadfree low firing glasses, detailed below, are available for use in PDP materials. The results suggest that low-melting phosphate glasses would be suitable as an alternative material for the Pb-based dielectric layer, sealants and barrier ribs in PDP.