• Title/Summary/Keyword: plastic analysis

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Pseudo plastic zone analysis of steel frame structures comprising non-compact sections

  • Avery, P.;Mahendran, M.
    • Structural Engineering and Mechanics
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    • v.10 no.4
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    • pp.371-392
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    • 2000
  • Application of "advanced analysis" methods suitable for non-linear analysis and design of steel frame structures permits direct and accurate determination of ultimate system strengths, without resort to simplified elastic methods of analysis and semi-empirical specification equations. However, the application of advanced analysis methods has previously been restricted to steel frames comprising only compact sections that are not influenced by the effects of local buckling. A concentrated plasticity method suitable for practical advanced analysis of steel frame structures comprising non-compact sections is presented in this paper. The pseudo plastic zone method implicitly accounts for the effects of gradual cross-sectional yielding, longitudinal spread of plasticity, initial geometric imperfections, residual stresses, and local buckling. The accuracy and precision of the method for the analysis of steel frames comprising non-compact sections is established by comparison with a comprehensive range of analytical benchmark frame solutions. The pseudo plastic zone method is shown to be more accurate and precise than the conventional individual member design methods based on elastic analysis and specification equations.

Development of a Five-Day Basic Microsurgery Simulation Training Course: A Cost Analysis

  • Singh, Masha;Ziolkowski, Natalia;Ramachandran, Savitha;Myers, Simon R.;Ghanem, Ali Mahmoud
    • Archives of Plastic Surgery
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    • v.41 no.3
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    • pp.213-217
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    • 2014
  • The widespread use of microsurgery in numerous surgical fields has increased the need for basic microsurgical training outside of the operating room. The traditional start of microsurgical training has been in undertaking a 5-day basic microsurgery course. In an era characterised by financial constraints in academic and healthcare institutions as well as increasing emphasis on patient safety, there has been a shift in microsurgery training to simulation environments. This paper reviews the stepwise framework of microsurgical skill acquisition providing a cost analysis of basic microsurgery courses in order to aid planning and dissemination of microsurgical training worldwide.

Influence of Website Attributes on the Visit to Plastic Surgery Websites (성형외과 의원의 웹 방문자 수에 영향을 미치는 웹 사이트 속성)

  • Cho, Yeong-Bin;An, Seong-Hyeon
    • Journal of Information Technology Applications and Management
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    • v.14 no.3
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    • pp.137-149
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    • 2007
  • Most of hospitals, especially small-scale hospitals, have tried to get customers through the Internet as what companies have done recently. There are various attempts that increase visits to one's web-site in plastic surgery hospitals. However, in plastic surgery, there have been few studies on which an attribute contributes to increase the number of web-site visit. In order to derive the important attributes on the number of visit, we compared functional attributes of 30 high-visit plastic surgery web-sites with those of 30 low-visit web-sites using statistical and data mining methods. For analysis, three methods have conducted including Multiple Discriminant Analysis (statistical method), Decision Trees (data mining method), and Artificial Neural Network (data mining method). Furthermore, results of each method have been evaluated one another. The result of this study shows that a few attributes like 'Simulating cyber plastic surgery program', 'recommendation of information' explain the number of the visitors between high and low visit web-site. The methodology employed in this study provides an efficient way of improving satisfaction of visitors of plastic surgery website.

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Evaluation of Member Plastic Deformation Demands for Dual Systems with Special Moment Frames (특수모멘트골조를 가진 이중골조시스템을 위한 부재소성변형 평가)

  • Eom, Tae-Sung;Kim, Jae-Yo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.5
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    • pp.41-51
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    • 2010
  • For safe seismic evaluation and design, it is necessary to predict the plastic deformation demands of members. In the present study, a quick and reasonable method for the evaluation of member plastic deformations of dual systems was developed on the basis of results of elastic analysis, without using nonlinear analysis. Plastic deformations of beams, columns, and walls are functions of member stiffness, story drift ratio, and moment redistribution determined from elastic analysis. For dual systems with rigid connections between walls and beams, an increase in the plastic deformations of beams due to the rocking effect was considered. The proposed method was applied to 8-story dual systems and the predicted plastic deformations were compared with the results of nonlinear analysis. The results showed that the proposed method accurately predicted the member plastic deformations with simple calculations, but that for the accurate evaluation of member plastic deformations, the inelastic story drift ratio must also be predicted with accuracy. The proposed method can be applied to both the performance-based seismic design of new structures and the seismic evaluation of existing structures.

Finite element analysis of long-term changes of the breast after augmentation mammoplasty: Implications for implant design

  • Myung, Yujin;Lee, Jong-Gu;Cho, Maenghyo;Heo, Chan Yeong
    • Archives of Plastic Surgery
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    • v.46 no.4
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    • pp.386-389
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    • 2019
  • The development of breast implant technology continues to evolve over time, but changes in breast shape after implantation have not been fully elucidated. Thus, we performed computerized finite element analysis in order to better understand the trajectory of changes and stress variation after breast implantation. The finite element analysis of changes in breast shape involved two components: a static analysis of the position where the implant is inserted, and a dynamic analysis of the downward pressure applied in the direction of gravity during physical activity. Through this finite element analysis, in terms of extrinsic changes, it was found that the dimensions of the breast implant and the position of the top-point did not directly correspond to the trajectory of changes in the breast after implantation. In addition, in terms of internal changes, static and dynamic analysis showed that implants with a lower top-point led to an increased amount of stress applied to the lower thorax. The maximum stress values were 1.6 to 2 times larger in the dynamic analysis than in the static analysis. This finding has important implications for plastic surgeons who are concerned with long-term changes or side effects, such as bottoming-out, after anatomic implant placement.

Fatigue and Robust Analysis for Improving the Suspended Pedal of Vehicles (차량용 서스펜디드 페달 구조체의 피로 내구 분석 및 설계 개선)

  • Lee, Woo-Hyung;Hwang, Bum-Chul;Kim, Chul;Bae, Won-Byong
    • Journal of the Korean Society for Precision Engineering
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    • v.26 no.7
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    • pp.105-111
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    • 2009
  • This study was carried out to evaluate structural stability of the suspended plastic pedal used in vehicles and to predict its fatigue life with the results obtained from finite element analysis. And also shape optimization was performed to reduce its weight. Structural analysis of the suspended plastic pedal was based on the evaluation tests such as static test, stiffness test, and fatigue test in the actual field, which were frequently carried out in the companies manufacturing plastic pedals. The evaluation for the plastic pedal was carried out by structural and fatigue analyses using a commercial FEA program and according to it, maximum stress and strain and fatigue life of the pedal satisfied all the requirements in the evaluation tests. The results of structural analysis of the suspended plastic pedal were used in the fatigue analysis. Fatigue test was performed to verify validity of the theoretical fatigue life of the plastic pedal. And the life by theoretical calculation was in good agreement with that by the experiment. Object function for optimizing shape of the plastic pedal is its volume, and total volume of the plastic pedal was reduced to about 11.7% through shape optimization.

Experimental and Numerical Approach for Warpage Characteristics of Plastic Orthogonal Stiffened Structure (플라스틱 직교 보강 구조물의 휨특성에 대한 실험과 해석적 접근)

  • Kim M.Y.;Cho Y.J.;Lee Sung-Hee
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.1997-2000
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    • 2005
  • In this work, the effects of orthogonal ribs on warpage of plastic structure through injection molding process were investigated. Three kinds of injection molds were prepared to perform injection molding experiments of orthogonal stiffened plastic plate. The warpage of each injection molded specimen was measured using 3D CMM. And plastic injection molding analysis with commercial code was performed for the presented model. Numerical results of injection molding analysis were compared with those of experiments. It was shown that orthogonal ribs have a significant effect on the warpage of the structure in both cases of experiment and numerical analysis.

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Domain Decomposition Method for Elasto-Plastic Problem (탄소성문제 적용을 위한 영역분할법)

  • Bae, Byung-Kyu;Lee, Joon-Seong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.8
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    • pp.3384-3390
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    • 2011
  • This paper describes a domain decomposition method of parallel finite element analysis for elasto-plastic structural problems. As a parallel numeral algorithm for the finite element analysis, the authors have utilized the domain decomposition method combined with an iterative solver such as the conjugate gradient method. Here the domain decomposition method algorithm was applied directly to elasto-plastic problem. The present system was successfully applied to three-dimensional elasto-plastic structural problems.

Finite Element Analysis for Fatigue Crack Closure Behavior Using Reversed Plastic Zone Size (되풀이 소성영역 크기를 이용한 피로 균열 닫힘 거동의 유한요소해석)

  • Choi, Hyeon-Chang
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.10
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    • pp.1703-1711
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    • 2003
  • An elastic-plastic finite element analysis is performed to investigate detailed closure behaviour of fatigue cracks in residual stress fields and the numerical results are compared with experimental results. The finite element analysis performed under plane stress using contact elements can predict fatigue crack closure behaviour. The mesh of constant element size along crack surface can not predict the opening level of fatigue crack. Specially, the mesh of element sizes depending upon the reversed plastic zone size included the effect of crack opening point can precisely predict the opening level. By using the concept of the mesh of element sizes depending upon the reversed plastic zone size included the effect of crack opening point, the opening level of fatigue crack can be determined very well.