• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 1999년도 제3회 압연심포지엄 논문집 압연기술의 미래개척 (Exploitation of Future Rolling Technologies)
• /
• pp.313-319
• /
• 1999

The development of deformation texture in FCC polycystalline metals during rolling was simulated by the finite element analysis using a large-deformation, elaatic-plastic, rate-dependent polycrystalline model of crystal plasticity. Different plastic anisotropy due to different orientation of each crystal makes inhomogeneous deformation. Assuming plane strain compression condition, the simulation with a high rate sensitivity resulted in main component change from Dillamore at low rate sensitivity to Brass component.

• Geomechanics and Engineering
• /
• 제1권4호
• /
• pp.263-274
• /
• 2009

The modified Cam clay (MCC) model is used to study the response of virgin compressed clay in undrained compression. The MCC deviatoric stress-strain relationship is obtained in closed form. Elastic and plastic deviatoric strains are taken into account in the analysis. For the determination of the elastic strain components, both a variable shear modulus and constant shear modulus are considered. Constitutive relationships are applied to the well-known London and Weald clays sheared in undrained compression.

• 대한조선학회논문집
• /
• 제35권1호
• /
• pp.61-71
• /
• 1998

본 논문에서는 2차원 공간에서의 탄성 또는 탄소성응력파를 받는 구조부재의 동적 파괴거동을 다룬다. 이러한 문제에 대한 지배방정식은 운동방정식과 탄소성 구성방정식에 대한 증감식으로 구성된 쌍곡선 편미분 방정식으로 나타나고, 이를 풀기 위해 유한차분법을 기초로 한 Zwas방법이 도입된다. 또한 탄소성문제의 동적거동을 나타내기 위해 응력공간내 탄소성 loading path가 소성항복 현상을 모델링하는데 제안된다. 이러한 계산결과를 바탕으로 탄성체의 균열선단의 동적응력확대계수가 계산되어지고, 탄소성체에 대한 소성영역의 형상의 시간이력을 보여준다.

• Archives of Plastic Surgery
• /
• 제49권1호
• /
• pp.34-38
• /
• 2022

The deep inferior epigastric perforator (DIEP) flap has been widely used for autologous breast reconstruction after mastectomy. In the conventional surgical method, a long incision is needed at the anterior fascia of the rectus abdominis muscle to obtain sufficient pedicle length; this may increase the risk of incisional hernia. To shorten the incision, several trials have investigated the use of endoscopic/robotic devices for pedicle harvest; however, making multiple additional incisions for port insertion and operating in the intraperitoneal field were inevitable. Here, we describe the first case, in which a DIEP free flap was successfully made using the da Vinci SP model. Our findings can help surgeons perform operations in smaller fields with a single port in the extraperitoneal space. Moreover, this method is expected to lead to fewer donor-related complications and faster healing.

• Geomechanics and Engineering
• /
• 제28권1호
• /
• pp.89-105
• /
• 2022

The behavior of the soil subgrade is complex and irregular against loads. When modeling, the soil is often replaced by a more straightforward system called a subgrade model. The Winkler method of linear elastic springs is a popular method of soil modeling in which the spring constant shows the modulus of subgrade reaction. In this research, the factors affecting the distribution of the modulus of subgrade reaction of elastoplastic subgrades are examined. For this purpose, critical theories about the modulus of subgrade reaction were examined. A square raft foundation on a sandy soil subgrade with was analyzed at different internal friction angles and Young's modulus values using ABAQUS software. To accurately model the actual soil behavior, the elastic, perfectly plastic constitutive model was applied to investigate a foundation on discrete springs. In order to increase the accuracy of soil modeling, equations have been proposed for the distribution of the subgrade reaction modulus. The constitutive model of the springs is elastic, perfectly plastic. It was observed that the modulus of subgrade reaction under an elastic load decreased when moving from the corner to the center of the foundation. For the ultimate load, the modulus of subgrade reaction increased as it moved from the corner to the center of the foundation.

• Archives of Plastic Surgery
• /
• 제37권4호
• /
• pp.391-395
• /
• 2010

Purpose: Given that the critical nature of the microvascular anastomosis to what is often a long and difficult reconstructive operation, trainees need to have a high level of microsurgical competence before being allowed to perform microsurgery on patients. Some artificial substitutes and dead or live animal models have been used to improve manual dexterity under the operating microscope. Yet, most surgeons are not equipped with such models, so search for easy available and appropriate microsurgical practice model have been an issue. Umbilical artery, placental vessels and gastroepiploic arteries have been previously suggested as a microsurgical training model, which involves other surgical departments. The purpose of this article is to introduce that saphenous vein specimen obtained from varicose vein surgery is useful and has many advantages as training model for the practice of microvascular anastomosis. Methods: The conventional technique using perforation/inversion method with a metallic stripper is widely performed for varicose vein patients. The stripper is inserted through disconnected safeno-femoral junction and retrieved at the knee or the medial side of ankle. The length of saphenous vein specimens removed is about that of one's leg and inversed from inside out. Obtained saphenous vein specimens are re-inversed and cleansed with normal saline, to be readily available for microsurgical practice. Preserved in a squeezed wet saline gauze and refrigerated, frozen or glycerated specimens were investigated into their comparative quality for microsurgical practice. Results: Varicose vein surgery remains one of the common operations performed in the field of plastic surgery. Convenient informed consent regarding the vessel donation can be easily signed. The diameter of the obtained saphenous vein is as variable as 1.5 to 6 mm, which is already stripped, and is in sufficient length corresponding to that of patient's leg. Vessels specimens were available for microsurgical practice within 1 week period when preserved with squeezed wet saline gauze, and the preservation period could be extended monthly by freezing it. Conclusion: Saphenous vein obtained from varicose vein patients provide with variable size of vessel lumen with sufficient length. The practice can be cost effective and does not require microsurgical laboratory. Additionally there is no need of involving other surgical departments in acquiring vessel specimens. Furthermore, simple preservation method of refrigerating for a week or freezing with squeezed wet saline gauze for a month period, allow the saphenous vein obtained after varicose vein surgery as an excellent model for the microsurgical practice.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 연약지반처리위원회 학술세미나
• /
• pp.79-92
• /
• 2000

In this paper, comparison of the observed and the predicted ground deformations due to the construction of road embankment with peck drain near the construction site was made. Measurement of the ground deformation at the gasoline stand due to the construction of road embankment was made and it was compared with the predicted deformation results of Finite Element Method analysis made with Elasto-plastic and Elastic visco-plastic models. A well agreement was obtained between the measured and predicted ground deformations.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1993년도 가을 학술발표회논문집
• /
• pp.131-138
• /
• 1993

To analysis machanical behavior for RC frame under monotonic & Cyclic load, it is needed to investigate elasto-plastic behavior for steel & concrete. Therefore, in this study, we idealized material model(steel and concrete) to take into account elasto-plastic, limit state, and developed structural analysis program that consider complex non-linearity. We investigated simple beam and portal frame under cyclic & monotonic loading, so we confirmed the propriety.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
• /
• pp.49-54
• /
• 1997

In this paper, vibration characteristics are considered about thermo-visco-plastic material under periodic thermal loading. When in high temperature region, thermo-visco-plastic structure has a periodic thermal loading, it is very important in an accumulated structure like a spacestation to investigate vibration characteristic, stress-strain characteristic is considered in various 2-D model by finite element method.

• Selected Papers of The Society of Naval Architects of Korea
• /
• 제1권1호
• /
• pp.26-36
• /
• 1993

In this paper, a thoery for the static analysis of large plastic deformations of 3-dimentional frames, aiming at application to the collapse analysis of ship structures, is presented. In the frame analysis formulation, effects of shear deformations are included. A plastic hinge is inserted into the field of a beam and post-failure deformation of the plastic hinge is characterized by finite rotations and extensions. In order to model deep web frames of ship's structures into a framed structures, collapse of thin-walled plate girders is investigated. The proposed analysis method is applied to several ship structural models in the references.