• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1692-1699
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• 2015

This paper presents an analysis of the mechanism of failure modes in bi-directional phase-shift full-bridge converters, composed of MOSFET, based on the circuit operation and parasitic parameters of MOSFET. In addition, the relation between circuit operation and parameters is suggested through an experimental comparison. From this relation, the suitable ranges of parameters for stable performance are analyzed. The design criteria of the bi-directional phase-shift full-bridge converter are presented and evaluated from the experimental verification.

• Journal of Korean Society for Quality Management
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• v.25 no.1
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• pp.156-172
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• 1997

FMEA is a widely used technique to assess or to improve reliability of products at early stage of design and development. In order to implement FMEA effectively, it is important to utilize knowledge or technical know-hows. However, that is very difficult. In fact, if information on the failure modes is enough, it is important to consider a counterplan to eliminate critical failure modes. If engineers do not have such information, however, it is more important to know what failure modes of the component under consideration would undergo. This means that the purposes of performing FMEA varies according to the situation. Therefore, we need different kinds of FMEA charts to meet those purposes. This paper proposes two FMEA charts: one is suitable for detecting potential failure modes and the other is for product improvements.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.167-177
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• 2009

This study investigates a failure mechanism of a tunnel shotcrete lining with respect to a concentrated load due to blocky rock mass. First of all, it is carried out to survey relevant researches to shotcrete failures by literature reviews and to numerically re-investigate the failure modes of shotcrete lining given by previous researches. Through this study, the failure modes are relocated with the conditions which induce each failure mode newly proposed by this study. In addition to this, the arching shape of tunnel lining, which has not been considered in the previous research despite of inherent geometrical characteristics in tunnels, is taken into consideration in numerical investigation on lining failure in this study. As a result, it is shown that more simplified failure modes can be found on the tunnel boundary condition and the corresponding failure condition to each mode can be different from ones of the previous study due to a tunnel arching effect.

• Steel and Composite Structures
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• v.25 no.1
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• pp.35-43
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• 2017

This paper presents the findings of experimental and numerical investigations on failure analysis and structural behavior of notched steel I-beams reinforced by bonded Carbon Fiber Reinforced Polymer (CFRP) plates under static load. To find solutions for preventing or delaying the failures, understanding the CFRP failure modes is beneficial. One non-strengthened control beam and four specimens with different deficiencies (one side and two sides) on flexural flanges in both experimental test and simulation were studied. Two additional notched beams were investigated just numerically. In the experimental test, four-point bending method with static gradual loading was employed. To simulate the specimens, ABAQUS software in full three dimensional (3D) case and non-linear analysis method was applied. The results show that the CFRP failure modes in strengthening of deficient steel I-beams include end-debonding, below point load debonding, splitting and delamination. Strengthening schedule is important to the occurrences and sequences of CFRP failure modes. Additionally, application of CFRP plates in the deficiency region prevents crack propagation and brittle failure.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.317-322
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• 2003

The Sectional and Spatial failure modes are discussed using the experimental data with long crest wave and multi-directional waves considering the failure modes occurring around the rubble-mound breakwater. The spatial & sectional stability and failure mode around the rubble-mound structures with construction progress can be summarized as follows: 1) The rubble mound structures at basic construction step was occurred serious failures when ${\xi}$ was about 6.5. 2) It was clarified that the failure modes at the round head of detached breakwater are classified as failure by plunging breaking on the slope, failure by direct incident wave force and failure by scouring at the toe of the detached break water. 3) The failure mode was found in the lower wave height than the design wave by the breaker depth effect. 4) The failure on the slope were also developed at the lee side of the round head because diffracted wave propagated into the behind area by grouping effect of multi-directional irregular wave.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.46-49
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• 2006

In general, the shear behavior mode of URM wall expresses four types of modes such as rocking failure, sliding shear failure, toe crushing failure, and diagonal tension failure. From the comparison of each equation according to the shear behavior modes, the failure modes based on the aspect ratio and vertical axial stress can be expected. The objectives of this study is to find out the shear behavior of URM wall with different aspect ratio. The test results show that the aspect ratio is understood as an important variable.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.34-39
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• 1989

Recent trends in design standards development have encouraged the use of probabilistic limit sate design concepts. Reliability analysis adopted in those advanced countries have the potentials that they afford for symplifying the design Process arid placing it on a consistent reliability based for various construction materials. This study is proposed in the reliability analysis of plane frame structures using second-order moment method(Level-II they). Lind-Hasofer's minimum distance method is use in the derivation of an mathematical algorithm as well as an determination of Correlation cofficients, reliability index and total reliability index depending on the multiple failure modes. In addition. This study is employed as a practical tool for the approximate reliability analysis. Results of the numerincal analysis showed that the difference between the reliability index of the failure probability of the multiple failure modes and the total reliability index of the failure probability with the simultaneous failure modes deviated nearly 3∼10% depending on tile performance functions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.135-138
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• 2003

Recently, sandwich structures have been widely employed in load bearing structures due to their high specific stiffness and high specific strength. Some sandwich structures are subjected to not only static loads but also impact loads which might induce failure of structures at far less load than expected. Since sandwich structures can fail in various modes, estimation of the impact energy absorption is difficult. In this work, the impact failure modes and the impact energy absorption characteristics of the sandwich beams were predicted by the FE analysis and confirmed by the impact test. From the analytic and experimental results, the impact failure mode map was constructed with respect to non-dimensional parameters.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.339-342
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• 1988

Typical magnetic bubble propagation failure modes of ion implanted magnetic bubble computer memory devices were observed and their failure mechanisms were analize. The skidding failure mode is due to the pushing of a strong repulsive charged wall. If this pushing is stronger than the edge affinity of the bubble in the cusp, the bubble moves out of the cusp when it is supposed to stay there. The stripeout failure modes across the adjacent track or along the track can be explained by considering the relative strength of the charged wall and the edge affinity encountered by both ends of the stripe. The skipping of the first cusp of a track is believed to be due to the whipping motion of the charged wall. The bubble moves directly to the second cusp via the long charged wall pointing to the second cusp skipping the first cusp.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.3
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• pp.259-264
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• 2000

The paper provides the characteristic analyses of porcelain suspension insulators. The comparisons of characteristics were made as a function of failed and unfailed insulators which had ben used in the fields. This paper also describes the failure modes occurred in the fields. The aging of cement corrosion of metal breaking of shed puncture in the head and separation of glaze are different failure modes for porcelain suspension insulators. Among these failure modes the puncture breaking and glaze problems were major concerns in this research. The cracks porosities of porcelain and micro-crystals on the graze were the causes of these failures. These results were confirmed by conducting various failure analyses.