• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.1-5
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• 2002

An approach for the damage of delamination which is the major concern during mechanical working for composite laminate material is proposed based on linear elastic fracture mechanics. This paper presents method evaluating of damage crack length using by average thrust force with AE characteristics. Also, the relations of AE characteristics are obtained from delamination damages. We found the onset ply of the delamination and a critical energy release rate and expressed a stress intensity factor by AEcount equation.

• Structural Engineering and Mechanics
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• v.6 no.8
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• pp.841-856
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• 1998

During the 1995 Hyogoken-Nanbu Earthquake, a reinforced concrete building, called Jeunesse Rokko, suffered intermediate damage by forming a beam-yielding (weak-beam strong-column) mechanism, which has been regarded as the most desirable earthquake resisting mechanism throughout the world. High cost to repair damage at many beam ends and poor appearance expected after the repair work made the owner decide to tear down the building. Nonlinear earthquake response analyses were conducted to simulate the behavior of the building during the earthquake. The influence of non-structural members was considered in the analysis. The calculated results were compared with the observed damage, especially the location of yield hinges and compression failure of spandrel beams, and the degree of cracking in columns and in column-girder connections.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.7 s.178
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• pp.1833-1840
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• 2000

Commercially pure copper is tested to obtain creep curves at 2500C. Constitutive relations adopting continuum damage mechanics concept is found to be appropriate to model the creep defor mation up to the tertiary stage. Microscopic observation by SEM reveals that creep condition induces cavities and microcracks subsequently. The constitutive equations along with evaluated creep parameters are implemented into finite element analysis code. The analysis reproduces creep curves under step loading as well as constant loading with reasonable accuracy. Distribution and evolution of damage under creep loading are numerically simulated for two different types of notched specimen. Predicted creep life agrees quite well with rupture test results. The influence of mesh size at notch tip on rupture time prediction is studied, and a degree of refinement is suggested for the specific notched specimens.

• Journal of Family Resource Management and Policy Review
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• v.9 no.4
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• pp.41-61
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• 2005

As e-commerce is expanding rapidly, the consumer's damage in the e-commerce is also dramatically increased. This research was mainly focused on the consumer's damage experiences through the e-commerce, the consumer's behavior's when they were confronted with troubles, and the way to handle their damages in the e-commerce. Main findings are as follows. 1) More than $90\%$ of respondents answered that they had experienced troubles at least once out of 49 troubles listed in the questionnaire. 2) Most consumers did complain their damages actively and tried to obtain proper cure from the seller. 3) Normally, they were used to adjust their purchasing behaviors to avoid the problems rather than actively taking advantage of the official authorities or private consumer organizations to solve the problems.

• Structural Engineering and Mechanics
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• v.44 no.4
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• pp.417-429
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• 2012

Taking the superficial temperature increment as the major fatigue damage indicator, the infrared thermography was used to predict fatigue parameters (fatigue strength and S-N curve) of welded joints subjected to fatigue loading with a high mean stress, showing good predictions. The fatigue damage status, related to safety evaluation, was tightly correlated with the temperature field evolution of the hot-spot zone on the specimen surface. An energetic damage model, based on the energy accumulation, was developed to evaluate the residual fatigue life of the welded specimens undergoing cyclic loading, and a good agreement was presented. It is concluded that the infrared thermography can not only well predict the fatigue behavior of welded joints, but also can play an important role in health detection of structures subjected to mechanical loading.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.89-92
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• 2002

Traditionally unidirectional laminated composite which are characterized by high specific stiffness and strength were used for structural application. But theses composites are highly susceptible to impact damage because of lower transverse tensile strength. The main failure modes of laminated composite are fiber breakage, matrix cracking and delamination for low velocity impact. The modified failure criterions are implemented to predict these failure modes with finite element analysis. Failure behavior of the woven fabric laminated composite which is used in forehead part of subway to lighten weigh has been studied. The new failure criterions are in good agreement with experimental results and can predict the failure behavior of the woven fabric composite plate subjected to low velocity impact more accurately.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.2
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• pp.251-261
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• 1997

According to consumer's washing behavior, the washing efficiency of three different types of washing machines-pulsator, agitator, and drum was studied. Their detergency, rinsing efficiency, and the degree of fabric damage, tangle, and wrinkle were evaluated. The results showed that efficient washing capacity was different from the specified capacity of washing machine. Detergency and rinsing efficiency frere apparently decreased when more than 50% of capacity was loaded in washing machine of pulsator type, and 80% for agitator or drum types. They were also affected by detergent adding methods, and decreased in the order of water-detergent-washing load> washing load-detergent-water> washing load-water-detergent. Rinsing efficiency was significantly improved when the rinsing temperature was set above washing temperature. In addition, it was revealed that detergency, fabric damage, wrinkle, and tangle were highly correlated. The relationships between detergency and tangle were different for different types of washing machine. Positive relationships were found for agitator and drum types, whereas negative for pulsator type.

• International Journal of Automotive Technology
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• v.1 no.2
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• pp.71-77
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• 2000

High temperature materials in service are subjected to mechanical damage due to operating load and metallurgical damage due to operating temperature. Therefore, when designing or assessing life of high temperature components, both factors must be considered. In this paper, the effect of tensile hold time on high temperature fatigue crack growth and long term prior thermal aging heat treatment on creep rupture behavior were investigated using STS 316L and STS 316 austenitic stainless steels, which are widely used for high temperature components like in automotive exhaust and piping systems. In high temperature fatigue crack growth tests using STS 316L, as tensile hold time increased, crack growth rate decreased in relatively short tensile hold time region. In long term aged specimens, cavity type microcracks have been observed at the interface of grain boundary and coarsened carbide.

• Wind and Structures
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• v.31 no.1
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• pp.1-14
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• 2020

This paper presents a method of estimation of fatigue demands on connection bolts of tubular steel wind turbine towers. The presented method relies on numerical simulation of aerodynamic loads and structural behavior of bolted connections modeled using finite element method. Variability of wind parameters is represented by a set of values derived from their probability densities, which are adjusted based on field measurements. Numerically generated stress time-series show agreement with the measurements from strain gauges inside bolts, in terms of power spectra and the resulting damage. Position of each bolt has a determining effect on its fatigue damage. The proposed framework for fatigue life estimation represents the complexities in loading and local behavior of the structure. On the other hand, the developed procedure is computationally efficient since it requires a limited number of simulations for statistically representing the wind variations.

• Sleep Medicine and Psychophysiology
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• v.1 no.1
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• pp.29-35
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• 1994

Overall purposes of neuropsychological tests are summarized as follows: 1) Indentifying brain damage in individuals who have symptoms of uncertain etiology; 2) Assessing the extent and nature of deficits for forensic purposes and planning appropriate intervention; 3) Evaluating the effects of intervention or rehabilitation; 4) Examining the effects of various types of brain damage across different populations; and 5) Testing theoretical propositions about brain-behavior relationship. Of the neuropsychological tests, the Luria-Nebraska Neuropsychological Battery(LNNB) is easily transportable, relatively inexpensive, and performable by trained technician. The Korean version of LNNB is now being designed and will be used clinically in the near future. Localization and equipotential theories of brain function had been prevalent until Luria's theory of brain function. Brain, composed of three brain units in the theory, is the functional system in which each brain area has specific function and produce the function-related behavior. LNNB consists of 11 clinical scales, 5 summary scales, 8 localization scales, and 28 factor scales.