• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2007.04a
• /
• pp.441-444
• /
• 2007

This paper presents a part of micormechanics-based elastic modeling (Lee and Pyo, 2007) of particle-reinforced composites containing slightly weakened interfaces. The Eshelby's tensor for a damaged ellipsoidal inclusion to model particles with slightly weakened interfaces is incorporated into a micormechanical formulation by Ju and Chen (1994). A damage model in accordance with the Weibull's probabilistic function is also developed to simulate the progression of weakened interface in the composites.

• 대한정형외과스포츠의학회:학술대회논문집
• /
• 2007.04a
• /
• pp.58-64
• /
• 2007

머리 위 던지는 운동선수는 전방 관절낭의 이완과 강력한 동적 안정성이 요구되므로 조금이라도 흔들리면 쉽게 견관절 통증이 유발될 수 있다. 이러한 상태가 계속되면 견관절 조직의 강한 스트레스로 손상히 발생하게 된다. 따라서 정확한 재활 프로그램을 통하여 효과적인 결과를 얻을 수 있다. 상해가 발생한 던지기 선수에서 내회전의 소실, 외회전근과 견갑근육의 약화를 교정하여 주는 것에 중점을 두고 치료한다. 추가적으로 재활에 성공한 선수에서 던지기 동작의 생역학을 평가하고 오류를 교정하면서 지속적인 교육을 시행하여 재발을 방지하고 원할한 동작을 수행하게 한다.

• Journal of Biomedical Engineering Research
• /
• v.20 no.5
• /
• pp.581-586
• /
• 1999

척추의 생체역학적 해석을 위한 유한요소기법을 이용한 컴퓨터 시뮬레이션은 척추의 손상에 대한 발생원인과 기전을 이해하고 치료의 효과를 예측하는 유용한 수단으로 기대되고 있다. 본 논문에서는 요추의 2차원 CT 영상을 이용하여 유한요소해석을 위한 척추의 3차원 모델링에 소비되는 많은 시간을 줄일 수 있도록 3차원 형상모델을 CT 형상 데이터와 형상변수를 이용, 각각 구현하는 과정을 자동화하여 이를 비교하였다.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.2 no.2
• /
• pp.77-81
• /
• 2003

Purpose: The biomechanics and kinematics of knee joint were reviewed in this article. And then the common sports injuries were presented. Anatomy and Kinetics: None of the pairs of bearing surfaces in the knee joint is exactly congruent This allows the knee six degrees of freedom of motion. Tibiofemoral Kinematics: In flexion and extension, the axis of motion is not perpendicular to the medial-lateral plane of the joint, nor is it perpendicular to the axis of longitudinal rotation. This results in coupled varus angulation and internal rotation with flexion and in valgus angulation and external rotation with extension. Patellofemoral Articulation: Loads across the patellofemoral joint are indirectly related to the angle of knee flexion and directly related to the force generated within the quadriceps mechanism. Fractures of the Patella: Nonoperative treatment is indicated if the extensor mechanism is intact and if displacement of fragment is minimal. The specific type of internal fixation depends on the fracture pattern. It is important to repair retinaculum. Acute and Recurrent Patellar Instability: The degree of dysplasia and the extent of the instability play a large part in determining the success of nonoperative treatment. Patients who experience recurrent dislocations and patients with major anatomic variations require surgery to minimize their instability. Sports Injuries in School-age Atheletes: Patellar pain in young athletes groups a number of conditions, including Idiopathic Adolescent Anterior Knee Pain, Osgood- Schlatter Disease, and Sinding-Larsen-Johansson Disease.

• Magazine of the Korea Concrete Institute
• /
• v.11 no.2
• /
• pp.177-186
• /
• 1999

The purpose of this study is to analyze the interface debonding of RC beams strengthened by carbon fiber sheet(CFS). The behavior of damaged RC beams strengthened with CFS is analytically investigated next using linear elastic fracture mechanics(LEFM) approach and the finite element method. The study includes an investigation of the separation mode by interface fracture of the strengthening materials due to the interfacial shear and normal stresses. The numerical method is presented to obtain the value of interfacial fracture parameter such as the strain energy release rate. Based on the results of this study, it is found that the critical case occurs when the interfacial cracks occur within a short region of the flexural crack. The CFS strengthening has not an adequate factor of safety against interfacial debonding of CFS. Furthermore, for the thicknesses of the adhesive studied[1mm~3mm], it is no noticeable effect on the strain energy release rate.

• Journal of the Korean Society for Railway
• /
• v.13 no.2
• /
• pp.194-200
• /
• 2010

Recently, a longitudinal tunnel construction has increased because of subway construction extension, geomorphological effect and the development of construction Technologies etc. When the fire occurs in a tunnel and an underground structure, the many damage of human life and the economic losses are caused. In Korea, fire resistance character study of a tunnel and an underground structure is proceeding. However, when a concrete is exposed to high temperature, study of load carrying capacity reduction and stability evaluation for spalling of a concrete is not enough. Therefore in this study, fire resistance character of a concrete evaluated according to time heating temperature curve(RABT and RWS) and a result compared on virtual fire accident in order to apply fire scenario. Also this study performed thermo-mechanical coupled analysis of a FEM-based numerical technique and estimated fire-induced damage of a tunnel and an underground structure.

• Research in Community and Public Health Nursing
• /
• v.10 no.2
• /
• pp.467-479
• /
• 1999

The mortality and morbidity caused by injury and poisoning has been major public health problem in Korea. This study was carried out to get information indispensable in developing prevention srategies peculiar to korean rural area. In this study 1.499 people of 496 households. who are living in five rural villages of Chooncheon City. Kang-Won Province. were interviewed in accordance with structured questionaire in 1996. The results obtained are summarized as follows: 1. The age-standardized annual incidence rates of injury and poisoning per 100 persons surveyed were 4.2 in males and 1.9 in females. The difference between sex was statistically significant. 2. The places where most of injuries and poisonings occurred were road 66.7% among males. road 31.6% among females. 3. The occurrence of the injuries and poisonings were clustered in intensive farming season in both males and females. 4. The laceration and stab wound were the most frequent nature of injuries in males and the fracture was the most frequent nature of injuries in females. The fracture. sprain were more frequent among males but sprain and contusion were more frequent among females. 5. Incidence rates of injuries and poisoning by cause were higher in traffic accidents among males. though falls among females. The cause specific incidence rate by age was high in traffic accident for 30-59 year age group. and for the aged people older than 60 years. 6. In the management pattern, 78.8% of the injuries and poisoning were received medical care in hospitals and clinics, and the duration of the treatment over 4 weeks in 37.0%. The results obtained indicate that organized community effort is urgently required to prevent injuries and poisonings in rural area.

• Composites Research
• /
• v.31 no.5
• /
• pp.251-259
• /
• 2018

In this paper, statistical volume element modeling method was developed for multi-scale progressive failure analysis of fiber reinforced composite materials. Big-size statistical volume elements (BSVEs) was considered to minimize the size effect in the micro-scale, by including as many fibers as possible. For that purpose, a mesh cutting method is suggested and adapted into the fiber model generator that creates finite element domain rapidly. The fiber defect model was also developed based on the experimental distribution of the fiber strength. The size effects from the local load sharing (LLS) are evaluated by increasing the fiber inclusion in the micro-scale model. Finally, continuum damage mechanics (CDM) model to the fiber direction was extracted from numerical analysis on BSVEs. And it was compared with strength prediction from typical representative volume element (RVE) model.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.4
• /
• pp.620-631
• /
• 2022

This paper shows the numerical prediction of the change in oil outflow rate according to the orifice shape of a damaged ship by using the computational fluid dynamics (CFD) analysis method. It also provides discharge coefficients for various orifice shapes to be used in theoretical prediction approaches. The oil outflow from the model ship was analyzed using a multiphase flow method under the condition that the Froude and Reynolds number similitudes were satisfied. The present numerical results were verified by comparing them with the available experimental data. Along with the aspect ratio of the orifice and the wall thickness of the cargo tank, the effects of the orifice shapes defined by mathematical figures on the oil outflow were investigated. To consider more realistic situations, the investigation of the ef ect of the crushed iron plate around the damaged part was also included. The numerical results confirmed the change in oil outflow time for various shapes of the damaged part of the oil tank, and discharge coefficients that quantify the viscous effects of those orifice shapes were extracted. To verify the predicted discharge coefficients, they were applied to an oil spill estimation equation. As a result, a good agreement between the CFD and theoretical results was obtained.

• The Journal of Korean Physical Therapy
• /
• v.16 no.2
• /
• pp.1-16
• /
• 2004

The purpose of this paper is to review changes in articular cartilage properties from the joint immobilization. Joint immobilization is accompanied not only by many disorders including rheumatologic disorders, degenerative disorders, trauma and fracture but treatment for disorders. Articular cartilage are sensitive to mechanical events. Immobilization is associated with cartilage degradation that may cause joint pain and reduced range of motion. An understanding of the effects of immobilization on the articular cartilage will help to plan of physical therapy program