• Journal of the Korean Society for Precision Engineering
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• v.26 no.9
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• pp.96-102
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• 2009

In this study, performs analysis of the life of parallel opening type pneumatic chucks that are usually applied in the factory automation line. Pneumatic chucks have complicated failure cause because they are organized as a complex of various elements. Therefore, we analyzed the main failure mode of pneumatic chuck, and then performed life test and performance test according to the international standards. On the basis of these processes, shape parameter of pneumatic chuk is proposed that is the main factor for the calculation of zero failure test time for the reliability of pneumatic chuck and their data analysis of life distribution.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.305-306
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• 2002

In this paper, the endurance life of the rolling bearings with defective balls and their failure (flaking) phenomena are presented. It was found that the lives of ball bearings with defective balls were shorter than that of calculated L10 life as well as that of normal bearings in spite of the using standard bearing components. Although the bearings were assembled with defective balls, whereas the other parts were qualified new ones, the main failures were occurred on the inner ring raceways. Moreover, the failures were on the center of the groove curvature and the severity of failure is similar to the order of initial defect depth of the balls. These shows that the defects on the bearings can affect the life of tribologically contacted mating parts.

• Korean Journal of Materials Research
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• v.15 no.1
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• pp.6-13
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• 2005

Copper based leadframe sheets were immersed in two kinds of hot alkaline solutions to form brown-oxide or blackoxide layer on the surface. The oxide-coated leadframe sheets were molded with epoxy molding compound (EMC). After post mold curing, the oxide-coated EMC-leadframe joints were machined to form sandwiched double-cantilever beam (SDCB) specimens. The SDCB specimens were used to measure the fracture toughness of the EMC/leadframe interfaces under quasi-Mode I loading conditions. After fracture toughness testing, the fracture surface were analyzed by various equipment to investigate failure path. An adhesion model was suggested to explain the failure path formation. The adhesion model is based on the strengthening mechanism of fiber-reinforced composite. The present paper deals with the introduction of the adhesion model. The explanation of the failure path with the proposed adhesion model was introduced in the companion paper.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.33-44
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• 1999

An energy balance procedure is developed to incorporate the effects of earthquake duration which involves the effect of cyclic loading and the corresponding cumulative plastic deformation. Particular emphasis is given to the flexural failure of non-seismically designed columns of reinforced concrete frames. For this, conceptual strength deterioration models for columns, governed by concrete, anchorage failure and longitudinal steel fracture due to low-cycle fatigue, are proposed. It is evident that the energy-based method has good agreement with the experimental data and is able to predict the failure mode.

• Aerospace Engineering and Technology
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• v.7 no.1
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• pp.183-193
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• 2008

This paper shows the results of failure mode analysis and the system-level reliability model for the flight test of KSLV-I upper stage. First, the critical 14 functions of KSLV-I upper stage are identified and the mission profile of the flight test is analyzed. Then, based on the functional analysis and the mission profile analysis, we construct a hierarchical structure of failure modes and a system-level reliability model for the flight test of KSLV-I upper stage.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.305-312
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• 2016

Purpose: The purpose of this study is to provide a sensitivity analysis of system reliability for recognizing effectiveness of changing of BD mode failures using reliability growth projection model based on NHPP. Methods: Crow extended reliability projection model (CERPM) is used to analyze the changing of two factors 1) the number of BD mode failures, 2) fix effectiveness factor (FEF) values. Results: The system reliability has increased in accordance with the number of BD mode failures and FEF values have increased. Conclusion: It is necessary to design failure modes and FEF values to supervise the reliability.

• Composites Research
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• v.18 no.1
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• pp.1-9
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• 2005

A methodology is presented for the failure prediction of composite single-lap bonded joints considering both of composite adherend failure and bondline failure. An elastic-perfectly plastic model of adhesive and a delamination failure criterion are used in the methodology. The failure predictions have been performed using finite element method and the proposed methodology. The failure prediction results such as failure mode and strength have very good agreements with the test results of joint specimens with various bonding methods and parameters. The influence of variations in the effective strength (that is, adhesion performance) and plastic behavior of adhesive on the failure characteristics of composite bonded Joints are investigated numerically. The numerical results show that optimal joint strength is archived when adhesive and delamination failure occur in the same time.

• 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.

• Journal of Industrial Technology
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• v.17
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• pp.213-218
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• 1997

This study is concerned with characteristics of bending collapse of aluminum members with multi-cell section. Aluminum is light so it is compatible of being used for vehicle structures members. Bending collpase behaviors of aluminum members with multi-cell section are very complex and tension failure mode are occured in experiment. In this paper, the aluminum members are modeled to be able to represent the tension failure mode and, characteristics of bending collapse of aluminum members with multi-cell section by experimental method are compared with the results of PAM-CRASH.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.787-790
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• 2000

This paper presents an experimental study on flexural behavior of structural member enlarged with epoxy mortar system. The main test variable is flexural tensile strength. A series of 4 test beams was tested to shoe the corresponding effect of each variables on maximum load capacity, load-deflection and moment-curvature relationship, interface behavior and failure mode. The results show that the flexural tensile strength of retrofitted materials have no relation load-deflection, but to load-strain, and failure mode.