A Rapid Online Calculation Method of Three-dimensional Plastic Deformation in Strip Rolling

Jian Shao,Chihuan Yao,Chaochao Chen,Wenquan Sun,Anrui He 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.2

Three-dimensional strip plastic deformation model is a key part of shape setup model in hot rolling. The numerical efficiency, accuracy and stability of the method are the main factors that may restrict its online application. Considering the theoretical limitations of existing models, basic equations include equilibrium equations with the effect of shear stress, constitutive equations based on incremental theory, and lubricated friction with the respective coefficients of friction at longitudinal and transverse direction. After normalization of parameters and the asymptotic analysis, the strip plastic deformation model is established, and solved by finite volume method and BICGSTAB algorithm to get the transverse distribution of rolling force of each stand. Compared to the finite element model established by ANSYS software, the new model has reliable results and a short computation time of 31 milliseconds, which show its feasibility of online application.

Three-dimensional numerical simulation of the temperature distribution within a large lithium-ion battery

Thien-Thanh Dao,김범근 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2

A one-dimensional model of an electrochemical battery does not adequately simulate thermal runaway in a large battery; a three-dimensional model is required. Here, we combine a one-dimensional electrochemical cell with a two-dimensional resistor network to simulate thermal distribution in a lithium-ion battery. Based on electrode current density and the potential distribution, the temperature distribution, as a function of discharge time is predicted using two principal source equations for heat generation: one for the electrochemical reaction and the other for the current collector resistance. The model outputs were in good agreement with the experimental data of Kim et al. [1]. Our results provide an overview of temperature distribution, and also the discharge curves at varying discharge rates. Our findings can be used to optimize the design of large batteries and control their thermal characteristics.

ON A THREE-DIMENSIONAL SYSTEM OF DIFFERENCE EQUATIONS WITH VARIABLE COEFFICIENTS

KARA, MERVE,YAZLIK, YASIN,TOUAFEK, NOURESSADAT,AKROUR, YOUSSOUF The Korean Society for Computational and Applied M 2021 Journal of applied mathematics & informatics Vol.39 No.3

Consider the three-dimensional system of difference equations $x_{n+1}=\frac{{\prod_{j=0}^{k}}z_n-3j}{{\prod_{j=1}^{k}}x_n-(3j-1)\;\(a_n+b_n{\prod_{j=0}^{k}}z_n-3j\)}$, $y_{n+1}=\frac{{\prod_{j=0}^{k}}x_n-3j}{{\prod_{j=1}^{k}}y_n-(3j-1)\;\(c_n+d_n{\prod_{j=0}^{k}}x_n-3j\)}$, $z_{n+1}=\frac{{\prod_{j=0}^{k}}y_n-3j}{{\prod_{j=1}^{k}}z_n-(3j-1)\;\(e_n+f_n{\prod_{j=0}^{k}}y_n-3j\)}$, n ∈ ℕ₀, where k ∈ ℕ₀, the sequences $(a_n)_{n{\in}{\mathbb{N}}_0$, $(b_n)_{n{\in}{\mathbb{N}}_0$, $(c_n)_{n{\in}{\mathbb{N}}_0$, $(d_n)_{n{\in}{\mathbb{N}}_0$, $(e_n)_{n{\in}{\mathbb{N}}_0$, $(f_n)_{n{\in}{\mathbb{N}}_0$ and the initial values x_-3k, x_-3k+1, …, x₀, y_-3k, y_-3k+1, …, y₀, z_-3k, z_-3k+1, …, z₀ are real numbers. In this work, we give explicit formulas for the well defined solutions of the above system. Also, the forbidden set of solution of the system is found. For the constant case, a result on the existence of periodic solutions is provided and the asymptotic behavior of the solutions is investigated in detail.

부유식 해양구조물 주위의 쇄파현상을 동반한 3차원 비선형성 파의 수치해석

박종천(Jong-Chun Park),宮田 秀明(Hideaki Miyata) 한국해양공학회 1996 韓國海洋工學會誌 Vol.10 No.3

Numerical simulation is made of the three-dimensional wave breaking motion about a part of a floating offshore structure containing a circular cylinder mounted vertically onto a lower hull in regular periodic gravity wave generated by a numerical wave maker. TUMMAC-Ⅷ finite-difference method is newly developed for such a problem. By use of density-function technique the three-dimensional wave breaking motion is approximately implemented in the framework of rectangular grid system. A porosity technique is devised for the implementation of the no-slip body boundary conditions. The generation of breaking waves by the interaction of incident waves with the structure is well simulated and interesting features of breaking waves are revealed with containing degree of quantitative and qualitative accuracy.

DLP 프린터로 제작한 상악 및 하악 의치상의 항온수조 침적에 따른 진실도(trueness) 평가

Kim Dong-Yeon,Lee Gwang-Young 대한치과기공학회 2024 대한치과기공학회지 Vol.46 No.2

Purpose: To evaluate the three-dimensional trueness of upper and lower denture bases produced using a digital light processing (DLP) printer and immersed in a constant-temperature water bath. Methods: An edentulous model was prepared and fitted with denture bases and occlusal rims manufactured using base plate wax. After scanning the model, denture bases, and occlusal rims, complete denture designs were created. Using the designs and a DLP printer, 10 upper and 10 lower complete dentures were manufactured. Each denture was scanned before (impression surface of upper denture base before constant temperature water bath [UBC] and impression surface of lower denture base before constant temperature water bath [LBC] groups) and after (impression surface of upper denture base after constant temperature water bath [UAC] and impression surface of lower denture base after constant temperature water bath [LAC] groups) immersion in the constant-temperature water bath. Scanned files were analyzed by comparing reference and scanned data, with statistical analysis conducted using the Kruskal-Wallis test (α=0.05). Results: Statistical analysis revealed no significant differences between the UBC and LBC groups, nor between the UAC and LAC groups (p>0.05). However, significant differences were observed between the UBC and UAC groups and between the LBC and LAC groups, i.e., before and after the constant-temperature water bath for both maxillary and mandibular denture bases (p<0.05). Conclusion: Denture bases not immersed in the constant-temperature water bath (UBC and LBC groups) exhibited error values within 100 μm, whereas those immersed in the water bath (UAC and LAC groups) showed error values exceeding 100 μm.

中韩保健教育背景差异性分析

여지연 동북아시아문화학회 2024 동북아 문화연구 Vol.1 No.78

With the development of society and people's attention to health, health awareness has gradually improved, and people have increasingly realized that health is a valuable wealth. In the 21st century with the high development of spiritual civilization and material civilization, it is required that the school education should train talents with all-round development. Health education has always been an important part of student education, and to a certain extent, students' health education is closely related to their own development and the development and progress of the whole society. Health education for students is a relatively important component, which mainly refers to the use of behavioral intervention and information dissemination to establish students' health concept, master health knowledge and voluntarily adopt an educational process and activity that is conducive to life style and healthy behavior. Both China and Korea are influenced by Confucianism and have certain commonalities in health education, but the differences in social systems and national histories also make health education in both countries different. Therefore, by comparing and analyzing the differences in the approaches, methods, contents, and goals of health education between China and Korea in the context of the four-dimensional linkage model, this paper can provide some inspirations for the development of health education in China: constructing a perfect early warning evaluation mechanism; developing lifelike health education, etc., so as to promote the improvement of health education. Please enter 2 more lines. Please enter 2 more lines. Please enter 2 more lines. Please enter 2 more lines

해양탐사장비 예인케이블의 3차원 동적해석에 관한 연구

정동호,김종규,박한일 한국해양학회 2003 바다 Vol.8 No.2

본 연구에서는 해양탐사장비를 예인하는 예인케이블에 관한 3차원 동적해석을 수행하였다. 해양케이블에 관한 지배방정식 중에서 굽힘강성 성분도 포함되는 보다 일반적인 지배방정식을 사용하였으며, 지배방정식은 3차원 비선형, 연성방정식이다. 예인선박의 예인속도와 측면주사음탐기의 중량에 따라서 예인단에서 발생하는 장력을 추정하였으며, 임의의 시간에 대한 케이블의 전체형상을 추정하였다. 정적해석결과를 통하여 특정한 수심에서 해양탐사장비를 예인할 때 예인속도를 잘못 조절한다면 관측장비가 해저면 바닥에 닿아서 탐사장비를 손실할 수 있다는 것을 알 수 있었다. 다양한 예인속도에 따른 예인단에서 장력의 변화를 살펴보았는데, 이를 통하여 예인단 장력은 예인속도가 임계속도보다 클 때는 접선하중성분이 지배적이고 작을 때는 자중효과가 지배적으로 나타난다는 것을 알 수 있었다. 또한 속도가 변하는 천이영역에서는 장력의 피크가 나타났으며 이것은 케이블에 충격력 효과로 작용할 수 있으므로 예인선박 운용에 이를 잘 고려해야 할 것이다. 본 연구결과는 다양한 해양탐사장비의 예인문제에 적용할 수 있을 것이다. In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is found in static analyses that the side-scan sonar must be towed to keep a its stable depth at a reasonable speed. The study also reveals in the transient analyses that the dominant component affecting the top tension is the tangential drag force for the larger towing speed than the critical speed, and the soft weight of a towed instrument for the smaller towing speed than. It should be maneuvered for a towing vessel with good consideration for the impact effect in a cable due to tension peak when a towing speed is suddenly increase. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

MULTIGRID SOLUTION OF THREE DIMENSIONAL BIHARMONIC EQUATIONS WITH DIRICHLET BOUNDARY CONDITIONS OF SECOND KIND

Ibrahim, S.A. Hoda,Hassan, Naglaa Ameen The Korean Society for Computational and Applied M 2012 Journal of applied mathematics & informatics Vol.30 No.1

In this paper, we solve the three-dimensional biharmonic equation with Dirichlet boundary conditions of second kind using the full multigrid (FMG) algorithm. We derive a finite difference approximations for the biharmonic equation on a 18 point compact stencil. The unknown solution and its second derivatives are carried as unknowns at grid points. In the multigrid methods, we use a fourth order interpolation to producing a new intermediate unknown functions values on a finer grid, and the full weighting restriction operators to calculating the residuals at coarse grid points. A set of test problems gives excellent results.

해양탐사장비 예인케이블의 3차원 동적해석에 관한 연구

정동호,박한일 韓國海洋大學校 附設 海洋科學技術硏究所 2002 硏究論文集 Vol.11 No.2

In this study, the configuration and tension of a towing cable for side-scan sonar are predicted in an ambient flow and at an unsteady towing condition. The governing equation of three-dimensional dynamic analysis for a flexible cable is solved using a finite difference method. We successfully predict the configuration and tension of a side-scan sonar and designed the towing system. It is sound that the side-scan must be towed to keep a its stable depth at a reasonable speed. The developed program can be applicable for three-dimensional dynamic analysis of a towing system for various marine survey instruments.

MULTIGRID SOLUTION OF THREE DIMENSIONAL BIHARMONIC EQUATIONS WITH DIRICHLET BOUNDARY CONDITIONS OF SECOND KIND

Hoda Ibrahim,Naglaa Ameen 한국전산응용수학회 2012 Journal of applied mathematics & informatics Vol.30 No.1

In this paper, we solve the three-dimensional biharmonic equation with Dirichlet boundary conditions of second kind using the full multigrid (FMG) algorithm. We derive a finite difference approximations for the biharmonic equation on a 18 point compact stencil. The unknown solution and its second derivatives are carried as unknowns at grid points. In the multigrid methods, we use a fourth order interpolation to producing a new intermediate unknown functions values on a finer grid, and the full weighting restriction operators to calculating the residuals at coarse grid points. A set of test problems gives excellent results.