• 터널과지하공간
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• 제15권4호
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• pp.288-295
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• 2005

암반은 여러 가지 지질학적 요인에 기인한 역학적 결함을 많이 포함하고 있기 때문에 이방성 거동을 보이는 경우가 대부분이다. 그러므로 안정한 암반구조물이나 암반기초의 설계를 위해서는 이방성 암반에서 응력분포의 특성을 이해하는 것이 매우 중요하다. 이 연구에서는 반무한 평면이방성 지반의 표면에 선하중이 작용할 때 지반에 야기되는 탄성응력 분포의 특성을 고찰하였다. 절리의 강성과 절리의 간격, 경사각이 응력분포 형태에 미치는 영향이 검토되었다. 절리면의 미끄러짐 조건으로 Mohr-Coulomb 식을 가정할 경우, 절리면을 통한 미끄러짐이 발생할 수 있는 영역에 대한 고찰도 수행되었다.

• 한국압력기기공학회 논문집
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• 제15권1호
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• pp.18-27
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• 2019

The Advanced Power Reactor 1400 (APR1400) Steam Generator (SG) uses alloy 690 as a tube material and SA-508 Grade 3 Class 1 as a tubesheet material to form tube-to-tubesheet joint through hydraulic expansion process. In this paper, the residual stresses in the SG tube-to-tubesheet contact area was investigated by applying Model-Based System Engineering (MBSE) methodology and the V-model. The use of MBSE transform system description into diagrams which clearly describe the logical interaction between functions hence minimizes the risk of ambiguity. A theoretical and Finite Element Methodology (FEM) was used to assess and compare the residual stresses in the tube-to-tubesheet contact area. Additionally, the axial strength of the tube to tubesheet joint based on the pull-out force against the contact joint force was evaluated and recommended optimum autofrettage pressure to minimize residual stresses in the transition zone given. A single U-tube hole and tubesheet with ligament thickness was taken as a single cylinder and plane strain condition was assumed. An iterative method was used in FEM simulation to find the limit autofrettage pressure at which pull-out force and contact force are of the same magnitude. The joint contact force was estimated to be 20 times more than the pull-out force and the limit autofrettage pressure was estimated to be 141.85MPa.

• Journal of Acupuncture Research
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• 제39권1호
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• pp.53-58
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• 2022

Fat pad syndrome is a knee joint condition/disease where acute or chronic inflammation occurs in the fat pad of the knee joint, and it is a cause of anterior knee pain. Fat pad syndrome usually occurs concurrently with other conditions/diseases to collectively cause anterior knee pain. No study to date has reported the treatment of anterior knee pain solely due to fat pad syndrome. Here, we report a case of fat pad syndrome of the knee joint as the sole cause of anterior knee pain in a 49-year-old woman who received integrated Korean medicine treatments (pharmacopuncture, acupuncture, herbal medicine, deep fascial meridian therapy, and chuna). Using patient-reported pain scale scores, the level of the patient's pain was relieved, and her mobility improved. Integrated Korean medicine treatments could be effective for patients who have fat pad syndrome of the knee joint.

• 대한족부족관절학회지
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• 제1권1호
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• pp.38-42
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• 1997

It was well known that arthrodesis of the tarsal joint is an exellent procedure to correct the flatfoot deformity for relieving pain. Recently, concept of the selective tarsal joint fusion instead of the triple fusion was developedto preserve the joint motion. To investigate and compare the effect of the each different tarsal fusion, we measured the strain at the spring ligament, medial roof of the medial longitudianl arch. Five fresh frozen cadevar foot specimens, with distal half of the tibia were utilized. The superomedial portion of the spring ligament complex was dissected from the origin to the insertion. For each specimen, a calibrated open liquid metal strain guage was secured along the length of the superomedial portion. Under the specially devised test rig, measurement of the strain was taken at each test condition from the tare weight 18.2 lb followed by 38.2 lb., 82.2 lb and a maximum loads of 134.6 lb. : 1) unfused condition, 2) isolated subtalar fusion 3) isolated talonavicular fusion 4) combined subtalar and talonavicular fusion 5) triple fusion. Statistics showed that siginificant reduction in strain following the triple fusion, and from the subtalar fusion to triple fusion.

• Journal of Welding and Joining
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• 제22권6호
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• pp.36-42
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• 2004

Experimental and numerical approaches on the thermal fatigue for the solder joint of flip chip package are discussed. However, it is one of the most difficult problems to choose the proper fatigue model. It was found that viscoplstic FE model with Darveaux method was very desirable and useful to predict the thermal fatigue life of solder joint for flip chip package under $208{\~}423K$ thermal cycling condition such as steep slope of temperature(JEDEC standard condition C). Thermal fatigue life was 1075 cycles as a result of viscoplatic model. It was a good agreement compared to the experimental. And also, it was found from the experimental that probability of the thermal fatigue life was $60{\%}$ at 1500 cycles.

• Journal of the Korean Wood Science and Technology
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• 제44권2호
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• pp.204-217
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• 2016

Modified poplar has emerged as a potential raw material for furniture production. Lack of specific modified poplar strength information; however, restricts applications in the furniture industry especially as related to strength in corner-joints. Optimization of strength in L-shaped corner dowel modified poplar joints under compression loads utilizing finite element analysis (FEA) by Taguchi method with the focus of this study. Four experiment factors (i.e., Structure Style, Tenon Length, Tenon Diameter, and Tenon Gap), each at three levels, were conducted by adopting a $L_9-3^4$ Taguchi orthodoxy array (OA) to determine the optimal combination of factors and levels for the von Mises stress utilizing ANSYS software. Results of Signal-to-Noise ratio (S/N) analysis and the analysis of variance (ANOVA) revealed the optimal L-shaped corner dowel joint in modified poplar is $45^{\circ}$ Bevel Butt in structure style, 24 mm in tenon length, 6 mm in tenon diameter, and 20 mm in tenon gap. Tenon length and tenon gap are determined to be significant design factors for affecting von Mises Stress. Confirmation tests with optimal levels and experimental test indicated the predicted optimal condition is comparable to the actual experimental optimal condition.

• 근관절건강학회지
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• 제11권1호
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• pp.7-17
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• 2004

In this paper, we checked health problems of patients who suffered from arthritis. After assessing each patients condition, in order to alleviate their sufferings, we introduced several methods of aromatherapy as a holistic approach to these health problems. Aromatherapy is used of essential oils, which are obtained from aromatic plants, can be defined as a nature-friendly complementary/alternative method, has its great merit in its each way of application. If the arthritis condition is localized, massage,compress or poultices, and hand or foot baths are most effective. Many of essential oils in the recipe have dual benefits, as anti-inflammative and analgesic agents. The Juniper and carrot seed aid in eliminating fluid and toxin accumulation in the joint and surrounding tissue. There are many different courses available and health professional should choose one that is relevant to clinical practice. Considering the future of nursing as a major contribution in the consumer-centered structure of medical health service, aromatherapy as a complementary/alternative method is expected to contribute not only to establishing more effective health service but also to resolving chronic health problems of arthritis.

• 한국정밀공학회지
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• 제23권4호
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• pp.75-82
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• 2006

In this paper, we propose an optimal trajectory for biped robots to move up-and-down stairs using a genetic algorithm and a computed-torque control for biped robots to be dynamically stable. First, a Real-Coded Genetic Algorithm (RCGA) which of operators are composed of reproduction, crossover and mutation is used to minimize the total energy. Constraints are divided into equalities and inequalities: Equality constraints consist of a position condition at the start and end of a step period and repeatability conditions related to each joint angle and angular velocity. Inequality constraints include collision avoidance conditions of a swing leg at the face and edge of a stair, knee joint conditions with respect to the avoidance of the kinematic singularity, and the zero moment point condition with respect to the stability into the going direction. In order to approximate a gait, each joint angle trajectory is defined as a 4-th order polynomial of which coefficients are chromosomes. The effectiveness of the proposed optimal trajectory is shown in computer simulations with a 6-dof biped robot that consists of seven links in the sagittal plane. The trajectory is more efficient than that generated by the modified GCIPM. And various trajectories generated by the proposed GA method are analyzed in a viewpoint of the consumption energy: walking on even ground, ascending stairs, and descending stairs.

• 대한기계학회논문집A
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• 제37권10호
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• pp.1297-1303
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• 2013

자동차 조향장치의 볼 조인트의 더스트 커버의 밀봉성과 응력 평가를 위하여 비선형 요한요소해석을 수행하였다. 주름형상과 항아리형상의 두 종류의 더스트 커버에 대하여 조립상태와 작동상태에 대하여 해석을 수행하여, 최대응력과 리브에서의 접촉응력 결과를 평가하고 비교하였다. 또한 작동상태에서의 몸통부 응력과 리브의 접촉응력이 조립상태 대비 증가하는 정도를 평가하였다. 해석 결과로부터 두 종류 모두 밀봉성이 우수한 것으로 확인되었으나, 상대적으로 최대응력이 작은 주름형상이 항아리형상보다 더 우수한 것으로 나타났다.

• 대한기계학회논문집
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• 제13권1호
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• pp.48-58
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• 1989

이 논문의 목적은 사용자가 부품간의 연결정보로는 단지 만남조건 (mating condition)만을 입력함으로써 조립체가 생성이 되고 또 그로부터 동역학 또는 기구학적 해석 프그램과의 연결을 위한 정보가 유도되는 조립체 모델링 시스템(assembly modeling system)을 개발하는 것이다. 만남조건을 통해 조립체를 생성하는 방법은 이미 Rocheleau와 Lee에 의해 개발되었으나 그들은 주로 각 부품의 위치를 찾아내는 데에만 관심을 두었고 본 논문에서는 그것의 확장으로 해석 프로그램과 연결시키는데 필요한 정보의 유도를 추가로 고려하였다.