• 한국자동차공학회논문집
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• 제21권4호
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• pp.166-173
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• 2013

An aluminum suspension corner module is widely used in high class passenger cars to reduce vehicle weight and improve fuel economy. According to the change of material and suspension type, the evaluation of the static strength and failure mode of the corner module is important. In this study, static strength and failure mode analysis of aluminium multi-link suspension corner module is presented. Static strength test system is designed and static failure mode tests of the corner module are carried out in longitudinal, lateral, and vertical direction. From the resuls of the tests we found that the failure modes are different compare to those of the steel corner module. The static failure modes and load-displacement curves of this study will be used as a guidance in design of a passenger car aluminium multi-link suspension corner module.

• Advances in Computational Design
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• 제3권1호
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• pp.71-86
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• 2018

Thin-walled cross-sections can be optimized to enhance their resistance and progress their behaviour, leading to more competent and inexpensive structural system. The aim of this study is to afford a methodology that would facilitate progress of optimized cold formed steel (CFS) column section with maximum ultimate strength for practical applications. The proposed sections are designed to comply with the geometrical standards of pre-qualified column standards for CFS structures as well as with the number of industrialized and practical constraints. The stiffening evaluation process of CFS lipped channel columns, a five different cross section are considered. The experimental strength and behaviour of the proposed sections are verified by using the finite element analysis (FEA). A series comprehensive parametric study is carried out covering a wide range of section slenderness and overall slenderness ratio of the CFS column with and without intermediate web stiffeners. The ultimate strength of the sections is determined based on the Direct Strength Specification and other design equation available from the literature for CFS structures. A modified design method is proposed for the DSM specification. The results indicate that the CFS column with complex edge and intermediate web stiffeners provides an ultimate strength which is up to 78% higher than standard optimized shapes with the same amount of cross sectional area.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2012년도 춘계학술대회
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• pp.225-226
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• 2012

최근 국내에서 섬유강화유리플라스틱(GRP)을 주로 사용하여 해양레저선박 및 구조물에 대한 건조가 이루어지고 있다. 하지만 해양레저 선박에 대한 구조강도 평가의 관심이 다소 미흡하다. 따라서 국내 실정에 적합한 구조강도평가기법을 정립하고 국내 규정 중 한국선급(KR)의 해양레저선박지침과 국토해양부의 강화플라스틱선 구조기준을 적용하여 구조설계 및 유한요소해석을 수행하여 신뢰성을 확보하고자 하였다.

• 한국지반환경공학회 논문집
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• 제18권3호
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• pp.5-14
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• 2017

극한지 동결 지반에서 구조물의 설계 및 시공이 진행됨에 따라, 안정성 평가를 위해 동결토의 강도 특성에 대한 실험적 연구가 필수적이다. 본 연구의 목적은 전단 상자 시스템에 따른 동결토의 강도를 평가하는 것으로, 이를 위하여 보편적으로 사용되는 기존 직접전단 시스템(Type-1), 상부 전단 상자 위쪽에 롤러를 설치한 시스템(Type-2), 그리고 상부 전단 상자를 하부 전단 상자와 분리되도록 기둥으로 고정한 시스템(Type-3)을 제작하였다. 모든 시스템에는 모래, 실트, 그리고 증류수를 동일한 비율로 혼합한 시료를 이용하여 조성하였으며, 냉동 챔버 내에서 $-5^{\circ}C$까지 동결된 후 연직 응력 5, 10, 25 그리고 50kPa을 가하며 직접전단실험을 수행하였다. 실험 결과, Type-1은 전단 이동에 따라 상부 전단 상자가 회전(rotation)하여 하부 전단 상자와 접촉하는 문제가 발생했다. 상부 전단 상자의 회전을 롤러로 방지한 Type-2의 경우, 회전을 막는 힘이 전단강도에 추가되어 강도가 과대 평가되었다. Type-3의 경우, 동결 시료만의 전단강도가 평가되었으며, 최대전단강도 발현 시점과 수직변위가 증가하기 시작하는 시점이 유사하게 나타났다. 또한, Type-3의 최대전단강도와 잔류전단강도의 내부마찰각과 점착력은 롤러의 영향이 제거되어 Type-2보다 작게 나타났다. 본 연구는 동결토와 같이 강도가 큰 시료의 경우 Type-3과 같이 개선된 전단 상자 시스템을 이용하여 동결토만의 강도를 평가할 수 있음을 보여준다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.194-197
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• 2001

Traction motors driven by high speed switching inverters is demanded higher operating temperature, severe duty cycles, higher starting current, frequent voltage transients and finally severe environmental exposure. For applications to inverter duty, traction motors needs a special insulation system, which has characteristics of increased bond strength, lower operating temperature and higher turn-to-turn insulation. In this paper, design considerations and manufacturing procedure of 200 Class insulation system with polyimde(Kapton) main insulation and silicone resin VPI process on the traction motor for EMU will be reviewed. And performance test and long life evaluation test which prove stability and long life evaluation test which prove stability and reliability of insulation system for traction motor will be introduced.

• Journal of Welding and Joining
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• 제19권4호
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• pp.379-383
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• 2001

Resistance spot welding has been widely used in the sheet metal joining processes because of low cost, high productivity and convenience. Recently, automobile and aerospace industries are trying to replace partly steel sheets with aluminum alloy sheets. But in the case of dissimilar materials, to apply resistance spot welding has been known to be very difficult owing to the effect of melting temperature. On this study, an effort was made to apply spot welding of dissimilar sheet metals, 2024 aluminum alloy and zinc coated steel sheet, evaluate the spot weld quality with tensile-shear strength test and nondestructive evaluation technique, C-scan image methodology. In this study results, as the current below 11 kA, melting of materials is not achieved well. Also as the current exceeds to 13.5 kA, the more spatters happen at welded zone and tensile-shear strength lowered. So, the feasibility of C-scan image technique proposed in the study is found to be suitable evaluation method for resistance spot weldability.

• Journal of Welding and Joining
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• 제12권2호
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• pp.97-107
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• 1994

Both in-process quality control and high reliability of the weld is one of the major concerns in applying friction welding to the economical and qualified mass-production. No reliable nondestructive monitoring method is available at present to determine the real-time evaluation of automatic production quality control for friction welding of special hydraulic valve spool of 16mm in diameter. This paper, so that, presents the experimental examinations and statistical quantitative analysis of the correlation between the initial cumulative counts of acoustic emission(AE) occurring during plastic deformation periods of the welding and the tensile strength and other properties of the welded joints of $\phi16$ valve spool as well as the various welding variables, as a new approach which attempts finally to develop real-time quality monitoring system for friction welding.

• 대한치과기공학회지
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• 제31권4호
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• pp.15-23
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• 2009

The aim of this study was to evaluate the bond strength of using a Au bonding agent applied on cp-Ti and nonprecious metal-gold-ceramic system. Metallic frameworks(diameter: 5mm, height: 20mm)(N=56, n=7per group) cast in Ni-Cr alloy, Co-Cr alloy and cp-Ti were obtained using acrylic templates and airborne particle abraded with $110{\mu}m$ aluminum oxide. Au bonding agent was applied on wash opaque firing as intermediate layer. SEM and SEM/EDS line profile were performed on the cutting the cross-section of the metal substrate-porcelain with intermediate Au coating. Groups were tested using shear bond strength(SBS) testing at 0.5mm/min. The mean SBS values for the ceramic-Au layer-metal combination were significantly higher than those ceramic-metal combination. While ceramic-Au layer-cp-Ti combinations failed to increase bond strength instead of using a titanium bonding porcelain. The appication of using Au intermediate layer significantly improve the bond strength combination with metal-ceramic system.

• Journal of Welding and Joining
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• 제23권6호
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• pp.87-92
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• 2005

It has been well hewn that ductile fracture of steels is accelerated by triaxial stresses. The characteristics of ductile crack initiation in steels are evaluated quantitatively using a two-parameters criterion based on equivalent plastic strain and stress triaxiality. The present study focuses on the effects of strength mismatch, which can elevate plastic constraint due to heterogeneous plastic straining, on the critical condition for ductile fracture initiation usinga two-parameter criterion. Fracture initiation testing has been conducted under static loading using notched round bar specimens which had different notch locations. This study provides the fundamental clarification of the effect of strength mismatching and effect of notch location on the critical condition to ductile crack initiation from notch root using fuite element method and ultrasonic-mechatronics system. The critical condition of ductile crack initiation from notch root of strength mismatched tensile specimens under static loading appeared to be almost the same as those of homogeneous tensile specimens with circumferential sharp notch specimen. Also, the effect of notch location in mismatched specimens was estimated using finite element(FE) analyses.

• 한국해양공학회지
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• 제22권2호
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• pp.91-98
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• 2008

In order to establish a design guide for the bottom plate structure of a 4.3 ton aluminum planning boat, the feasibilities of bottom plate scantling of the ship are investigated based on the results of structural strength analysis and a simple equation and evaluation system are developed for initial structural design purposes. This study consists of 5 steps: First, the background, necessity, and purpose of this study are explained briefly, Second, the principal dimensions of this ship, the position of the considered bottom plate members and material characteristics are introduced. Third, the equivalent design pressure concept is introduced and evaluated based on experience and experimental data. Fourth, the strength of bottom plate members are examined using elasto-plastic nonlinear structural analysis, and response levels and several boundary conditions are reviewed based on the analysis results. Finally, in order to suggest design guides in respect to the ship's structural design, a simple design equation and evaluation system for bottom plate members are suggested for boats in the 4.3 ton aluminumboat range through the introduction of safety factorsbased on the ultimate design pressure concept.