• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2006.03a
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• pp.79-93
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• 2006

It is well known that acoustic emission (AE) is indicator of rock fracturing or damage as rock is brought to failure under the uniaxial compressive loads. In this paper, an experimental study on the source location of acoustic emission on the cylindrical specimens of granite under uniaxial compression test was made. The AE source location was made by measuring the six channel AE data. Comparing to this experiment, the numerical method is applied to model the initiation and propagation of fracture by AE using a numerical code, RFPA (Realistic Failure Process Analysis). This code incorporates the mesoscopic heterogeneity in Young's modulus and rock strength characteristic of rock masses. In the numerical models, values of Young's modulus and rock strength are realized according to a Weibull distribution in which the distribution parameters represent the level of heterogeneity of the medium. The results of the simulations show that RFPA can be used not only to produce acoustic emission similar to those measurements in our experiments, but also to predict fracturing patterns under uniaxial loading condition.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.81-88
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• 2020

The damping hinge of a built-in refrigerator was examined in terms of its stress and fatigue life. Analysis of the initial design showed that stress concentration occurred at the concave surface of the hinge lever, which was broken during the door opening-and-closing endurance test of the prototype. The maximum von Mises stress at this location exceeded the yield strength. In addition, Goodman fatigue analysis of the initial design showed that the fatigue life at this location was consistent with the failure observed during the endurance test. Based on these results, an improved design for the damping hinge was derived. Analysis of this improved design showed that the stress concentration in the hinge lever of the initial design was eliminated. In this case, the maximum stress occurred at the position where the hinge lever was in contact with the door stopping pin, and the maximum von Mises stress was smaller than the yield strength. Goodman fatigue analysis of the improved design indicated that the fatigue life of the entire damping hinge was infinite. It was therefore concluded that the improved design does not suffer from fatigue damage during the endurance test.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.403-408
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• 2003

The objective of this study is to understand the variables affected the confinement for the transverse reinforcement of the reinforced concrete structural walls with the T-shaped cross section subjected to cyclic lateral loads. The structural performance of T-shaped walls was advanced by the transverse reinforcement which restrained the concrete subjected to compressive stress. If the arrangement of transverse reinforcement was not suitable for the confinement, T-shaped walls happened the brittle failure by web crushing or bucking of vertical reinforcement at the compression zone. It is necessary to confine transverse reinforcement in order to prevent the these failure. But the location of neutral axis and the magnitude of ultimate strain vary according to the section shape, a ratio of axial load, a ratio of wall cross sectional area to the floor-plan area, an aspect ratio and the reinforcement ratio. Therefore, the objective of this research is to grasp the location of neutral axis and the range which needs for the confinement of transverse reinforcement through the results of the sectional analysis which varies the ratio of axial load and the ratio of vertical reinforcement.

• Journal of the Korea Safety Management & Science
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• v.13 no.1
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• pp.195-202
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• 2011

The study interprets each of three classification models based on Bath-Tub Failure Rate (BTFR), Extreme Value Distribution (EVD) and Conjugate Bayesian Distribution (CBD). The classification model based on BTFR is analyzed by three failure patterns of decreasing, constant, or increasing which utilize systematic management strategies for reliability of time. Distribution model based on BTFR is identified using individual factors for each of three corresponding cases. First, in case of using shape parameter, the distribution based on BTFR is analyzed with a factor of component or part number. In case of using scale parameter, the distribution model based on BTFR is analyzed with a factor of time precision. Meanwhile, in case of using location parameter, the distribution model based on BTFR is analyzed with a factor of guarantee time. The classification model based on EVD is assorted into long-tailed distribution, medium-tailed distribution, and short-tailed distribution by the length of right-tail in distribution, and depended on asymptotic reliability property which signifies skewness and kurtosis of distribution curve. Furthermore, the classification model based on CBD is relied upon conjugate distribution relations between prior function, likelihood function and posterior function for dimension reduction and easy tractability under the occasion of Bayesian posterior updating.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.4
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• pp.147-155
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• 2019

In this study, flexural tests of granite reinforced with titanium metal rods were carried out to repair and restore the damaged stone-made cultural heritage, the Stone Pagoda of the Mireuksa Temple Site. A total of twelve specimens were tested. The primary test parameters are the reinforcement ratio and the location of the reinforcement. For restoration, epoxy resin was used for joining the separated stones, and titanium metal rods were used for structural reinforcement. Test results showed that the flexural failure took place in specimens with a reinforcement ratio of 0.8% or less, and shear failure occurred when the reinforcement ratio was 1.68% or more. The peak load of the reinforced stone was found to be highly related to the reinforcement ratio. The peak load increased with increasing the reinforcement ratio. Also, the flexural behaviors of the reinforced stones were affected by the location of the reinforcement. Based on the test results, this study recommends the reinforcement ratio of the reinforced granite to induce ductile behavior.

• Journal of Chest Surgery
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• v.23 no.2
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• pp.299-308
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• 1990

A review of 50 patients with primary mediastinal tumors or cysts has been done to evaluate clinical and pathological behavior of this heterogeneous group of tumors proved by either excision or biopsy from January 1980 to August 1989 at the cardiovascular department of surgery in Kyungpook National University Hospital. There were 30 males and 20 females in this series. The ages of patients ranged from 4 months to 64 years. The mean age of subjects was 30.4 years. Neurogenic tumors [14 cases, 28%] and teratoma [14 cases, 28%] were most frequently encountered and followed by thymoma [10 cases, 20%] and benign cysts [4 cases, 8%]. The anatomic location of the primary mediastinal tumors or cysts was classified as anterior mediastinum and middle or visceral mediastinum and paravertebral or costovertebral mediastinum on the basis of the Shields’ proposition. In 32 patients[64%], the tumors or cysts were located in anterior mediastinum and in 13 patients[26%], the tumors or cysts were located in paravertebral or costovertebral mediastinum. And the rest 5 patients[10%] had middle or visceral mediastinal tumors or cysts. One of the characteristic features of primary mediastinal tumors or cysts is that some mediastinal tumors or cysts have their own preferred location in the mediastinum. In our series, all of the 14 patients with teratoma and 10 patients with thymoma had the anterior mediastinal location, while 13 of the 14 patients with neurogenic tumors had the paravertebral mediastinal location. 14 patients[28%] were asymptomatic and they all were discovered via so-called “Routine” chest x-ray examination. 39 of 50 patients[78%] were benign. 11 patients[22%] were malignant and they were all symptomatic. 40 patients[80%] were treated with complete resection. 5 patients[10%] were treated with partial resection : 2 of malignant thymoma, 3 of lipoma, neuroblastoma, primary squamous cell carcinoma. The rest 5 patients[10%] were only biopsied: 2 of undetermined malignancy and 3 of hemangioma, lymphoma, primary squamous cell carcinoma. 4 of the 10 patients were treated with combination of irradiation and chemotherapy. Postoperative complications were as followings: Horner’s syndrome [4cases, ado], respiratory failure [3 cases, 6%], pleural effusion[3 cases, 6%], Wound infection[2 cases, 4%] and bleeding, pneumothorax, empyema. There were 5 postoperative deaths [10%]. One patient with neuroblastoma died from intraoperative massive bleeding, 3 patients died early postoperatively from respiratory failure with undetermined malignancy died late postoperatively from congestive heart failure due to direct invasion of the tumor to the heart.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.3
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• pp.297-304
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• 2012

For the assessment of the performance of a wind-turbine blade, a simulated loading test may be required. In this study, the blade behavior was investigated through numerical analysis using a dual-axis loading test, closely simulating the real operation conditions. The blade structure for the 100-kW-class wind-turbine system was modeled using the finite element (FE) program ANSYS. The failure criteria and buckling analysis under dual-axis loading were examined. The failure analysis, including fiber failure and inter-fiber failure, was performed with Puck's failure criterion. As the dual-axis load ratio increases, the relatively increased stress occurs at the trailing edge and skin surface 3300-3600 mm away from the root. Furthermore, it is revealed that increasing the dual-axis load ratio makes the location that is weakest against buckling move toward the root part. Thus, it is seen that the dual-axis load test may be an essential requirement for the verification of blade performance.

• Structural Engineering and Mechanics
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• v.89 no.3
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• pp.253-263
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• 2024

Slope stability is generally paid more attention to in slope protection works, especially for slope containing weak layers. Two indexes of safety factor and failure model are selected to perform slope stability. Moreover, the finite element limit analysis method comprehensively combines the advantage of the limit analysis method and the finite element method obtaining the upper and lower bounds of the safety factor and the failure mode under the slope stability limit state. In this study, taking a waste dump containing a weak layer as an engineering background, the finite element limit analysis method is adopted to explore the potential failure mode. Meanwhile, the sensitivity analysis of slope stability is performed on geometrical and geotechnical parameters of the waste dump. The results show that the failure mode of the waste dump slope is two wedges if the weak layer is located on the ground surface (Model A), while the slope can be observed as three wedges failure if the weak layer is below the ground surface (Model B). In addition, both failure modes are highly sensitive to the friction angle of the weak layer and the shear strength of waste disposal, and moderately sensitive to the heap height, the dip angle and cohesion of the weak layer, while the toe cutting has limited effect on the slope stability. Moreover, the sensitivity to the excavation of the ground depends on the location of the weak layer and failure mode.

• Journal of the Korean Dietetic Association
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• v.13 no.3
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• pp.277-294
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• 2007

The purposes of this study were to a) examine using status, b) measure the service quality attributes, c) analyze IPA and customer satisfaction, d) develop the LSM(Local Store Marketing) by location of K theme restaurant such as residential type(A), complex type(B) and downtown type(C). The questionnaires were handed out to 346 of 450(usage rate 76.9%). The statistical data analysis was completed using SPSS(ver 12.0) for descriptive analysis, $X^2$, t-test, ANOVA, reliability analysis, factor analysis, multiple linear regression. From an analysis on service quality attributes, most importance of service quality attributes was more highly perceived than performance of those, except for 'attractive exterior', 'variety of kid's menu', 'convenient facilities for kid' and perceived importance and performance were also significantly different by location of branch restaurant. The attributes to be improved were 'convenience of restaurant's parking lot', 'food tast', 'speedy service' and 'service competency' as branch A(residential type) restaurant, 'convenience of the restaurant location' as branch B(complex type) restaurant and 'convenience of the restaurant location' and 'speedy service' as branch C(downtown type) through IPA analysis. The Overall customer satisfaction was 3.74 and service quality factors had significant effect on overall customer satisfaction. Location of restaurant, which gives a great effect on its operation and marketing, has a important correlation with success or failure of restaurant business enterprises. Therefore, marketing strategy by restaurant location should be developed.

• Journal of Korean Society of Steel Construction
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• v.15 no.1
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• pp.41-50
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• 2003

Nondestructive Damage Evaluation (NDE) techniques yield the damage location and its size from the modal characteristics of pre-damaged and post-damaged structures. To predict the system reliability of the aging structure, results from the NDE are integrated into the element/component failure probabilities. The element/component failure probabilities can be calculated from failure functions for each element/component with the aid of techniques from a structural reliability analysis. In this paper, a method to estimate the system reliability of a structure that is based on the reliabilities of elements/components in a given structure is presented. The efficacy of the combination of the nondestructive damage detection and the structural reliability evaluation is demonstrated using pre-damaged and post-damaged modal data obtained from numerical simulations of a rigid frame.