• Title/Summary/Keyword: Boundary working

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Two-Dimensional Thermo-Viscopiastic Finite Element Analysis of Free Forginf for Large Ingot Considerinf Internal Contact Treament on One Deforming Body (변형하는 동일물체간의 접촉처리를 고려한 대형강괴 자유단조의 2차원 열점소성 유한요소해석)

  • 박치용;양동열
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 1995.10a
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    • pp.102-108
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    • 1995
  • Internal contact scheme between two free surfaces on one deforming body has been proposed by using the penalty method. It has been imposed to be internal boundary condition on two-dimensional thermo-viscoplastic finite element method so as to analyze one deforming body, which has two free surfaces penetrating each others. Analysis of side pressing with a circular void and a inclined elliptic hole have been carried out in order to verity the proposed contact scheme. A finite element code imposed internal boundary condition has been applied to two-dimensional analysis of free forging of large ingot with a void. Through the analysis, effects of working parameters in order to consolidate voids have been investigated.

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Development of a Wave Absorbing System Using an Inclined Punching Plate (경사형 타공판을 이용한 소파장치 개발)

  • 조일형;홍석원
    • Journal of Ocean Engineering and Technology
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    • v.18 no.1
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    • pp.1-6
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    • 2004
  • In this paper, the performance of a wave absorbing system using an inclined punching plate, was investigated. Using the multi-domain boundary element method (BEM), the reflection coefficients of an inclined punching plate were tested with various design parameters, such as inclined angle, porosity, and wave frequencies. To confirm the numerical solutions, the systematic model test was conducted at 2-D tank and square tank. The numerical results were in good agreement with the experimental results within the entire frequency range. It was found that an inclined punching plate had an excellent wave absorbing efficiency, compared to a horizontal one. Also, the optimal range of an inclined angle had an excellent wave absorbing efficiency, compared to a horizontal one the optimal range of the inclined angle is 10°<β<20°. The developed wave absorber was installed at KRISO's square basin, and is working effectively for various model tests.

INFINITELY MANY SOLUTIONS FOR (p(x), q(x))-LAPLACIAN-LIKE SYSTEMS

  • Heidari, Samira;Razani, Abdolrahman
    • Communications of the Korean Mathematical Society
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    • v.36 no.1
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    • pp.51-62
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    • 2021
  • Variational method has played an important role in solving problems of uniqueness and existence of the nonlinear works as well as analysis. It will also be extremely useful for researchers in all branches of natural sciences and engineers working with non-linear equations economy, optimization, game theory and medicine. Recently, the existence of infinitely many weak solutions for some non-local problems of Kirchhoff type with Dirichlet boundary condition are studied [14]. Here, a suitable method is presented to treat the elliptic partial derivative equations, especially (p(x), q(x))-Laplacian-like systems. This kind of equations are used in the study of fluid flow, diffusive transport akin to diffusion, rheology, probability, electrical networks, etc. Here, the existence of infinitely many weak solutions for some boundary value problems involving the (p(x), q(x))-Laplacian-like operators is proved. The method is based on variational methods and critical point theory.

Project Learning Enablers within Fragmented Construction Projects

  • Alashwal, Ali Mohammed
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.588-592
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    • 2015
  • Many studies have affirmed a negative influence of fragmentation on learning and knowledge sharing in construction projects. However, the literature overlooked enablers of learning within this context. The purpose of this paper is to explore the factors that facilitate project learning and ways to negate any unbecoming effects of fragmentation. Qualitative study used to explore the enablers through interviews administered to 11 top management individuals working in different construction projects in Malaysia. The findings revealed the following factors: participation, relationships, togetherness, and roles of project leader and coordinator. The role of boundary objects was also highlighted including information technology (IT), contract and procedures, drawings, specifications, and reports. The outcome of this paper initiates the development of a model for better knowledge creation and sharing in construction projects. The significance of this model stems from its ability to connection both the characteristics of construction project and project learning theories using the enablers. It is envisaged that future work will be to confirm the model in a quantitative study.

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How is the inner contour of objects encoded in visual working memory: evidence from holes (물체 내부 윤곽선의 시각 작업기억 표상: 구멍이 있는 물체를 중심으로)

  • Kim, Sung-Ho
    • Korean Journal of Cognitive Science
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    • v.27 no.3
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    • pp.355-376
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    • 2016
  • We used holes defined by color similarity (Experiment 1) and binocular disparity (Experiment 2) to study how the inner contour of an object (i.e., boundary of a hole in it) is encoded in visual working memory. Many studies in VWM have shown that an object's boundary properties can be integrated with its surface properties via their shared spatial location, yielding an object-based encoding benefit. However, encoding of the hole contours has rarely been tested. We presented objects (squares or circles) containing a bar under a change detection paradigm, and relevant features to be remembered were the color of objects and the orientation of bars (or holes). If the contour of a hole belongs to the surrounding object rather than to the hole itself, the object-based feature binding hypothesis predicts that the shape of it can be integrated with color of an outer object, via their shared spatial location. Thus, in the hole display, change detection performance was expected to better than in the conjunction display where orientation and color features to be remembered were assigned to different parts of a conjunction object, and comparable to that in a single bar display where both orientation and color were assigned into a single bar. However, the results revealed that performance in the hole display did not differ from that in the conjunction display. This suggests that the shape of holes is not automatically encoded together with the surface properties of the outer object via object-based feature binding, but encoded independently from the surrounding object.

The Effect of Initial α' on Low and High Cycle Fatigue Behavior of STS 304 Stainless Steel (STS 304 강의 저주기 및 고주기 피로에 있어 초기 마르텐사이트의 영향)

  • Lee, Hyun-Seung;Sin, Hyung-Ju;Kim, Song-Hee
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.331-339
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    • 2001
  • Zero to tension fatigue tests and strain controlled fatigue tests were carried out to find how initial strain induced martensite, ${\alpha}^{\prime}$ affects low and high cycle fatigue behavior and fatigue crack growth mechanisms. Microscopic study and phase analysis were carried out with TEM, SEM, EDAX, Optical Microscope, Ferriscope, and X-ray diffractometry. The amount of Initial ${\alpha}^{\prime}$ was controlled from 0% to 33% by controlling the temperatures for cold working and heat treatment. Lower contents of initial ${\alpha}^{\prime}$ showed higher fatigue resistance in low cycle fatigue but lower fatigue resistance in high cycle fatigue because it is ascribed to the more transformation of ${\alpha}^{\prime}$ martensite during low cycle fatigue and higher ductility. In high cycle fatigue, fatigue life is attributed to the strength and phase transformation of austenite into ${\alpha}^{\prime}$ during fatigue was negligible. ${\gamma}$ boundary, ${\gamma}/twin$ boundary, and ${\gamma}/{\alpha}^{\prime}$ boundary were found to be the preferred site of fatigue crack initiation.

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The Numerical Analysis of Fluid Flow in the Tube Cleaning System (튜브 클리닝 시스템 내부의 유동 특성에 관한 수치해석적 연구)

  • Jung, Kyung-Chul;Lee, Chi-Woo
    • Journal of Power System Engineering
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    • v.18 no.1
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    • pp.63-68
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    • 2014
  • The numerical analysis of fluid flow in the tube cleaning system is examined. The working flow used in this study is seawater, and the temperature change is not considered as the temperature change of seawater in the tube cleaning system is negligible. Also, the analysis is performed under the assumption of steady state. The screens of complicated morphologies are simplified for the analysis, and only one fourth of the tube cleaning system is modeled as the system has a symmetrical shape. The velocity inlet boundary condition is employed for the seawater inlet, whereas the outflow boundary condition is employed for two seawater outlets. In applying the outflow boundary condition for the system with more than two outlets, the flow rate can be arbitrarily assigned. In the analysis, the finite-volume method based numerical analysis tool, the pressure based solver, the standard k-$\varepsilon$ model are utilized, and the under relaxation factor is modified appropriately. From the analysis, the distribution of velocity vectors, pressure and path lines are obtained, and the physical characteristics of fluid flow in the tube cleaning system is well-examined.

Study of Cam and Follower Contacts with the Mixed Concepts of EHL and Boundary Lubrication (EHL과 경계 윤활의 혼합 개념에 의한 캠과 종동물의 접촉 현상에 대한 연구)

  • 장시열
    • Tribology and Lubricants
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    • v.15 no.4
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    • pp.343-353
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    • 1999
  • The role of viscosity index improver's(Ⅶ) additives for modem engine lubrication is complex. Under the condition of atmosphere or low shear rate, the characteristics of Ⅶ added lubricant is verified and quoted frequently for mathematical model of lubricant behavior. However, recent research shows that added lubricant has the characteristics of shear thinning at high shear rate condition although it performs well enough over the whole range of working temperature. At high shear rate, they show significant decrease of apparent viscosity irrespective of temperature. Many experimental researches verify that Ⅶ added lubricant shows boundary film layer formation on the solid surface as well as shear thinning effect by its polymeric molecular characteristics. The intend of our research is to verify the effects of Ⅶ from the viewpoint of continuum mechanics, because conventional Reynolds'equation with only pressure-viscosity relation cannot fully predict the lubricant behavior under the Ⅶ added condition. In these aspects, Reynolds'equation of Newtonian fluid model lacks the reflection of real fluid behavior and there is no way to explain the non-linear characteristics of Ⅶ added lubricant. In this research, we mathematically modeled the Ⅶ added lubricant behaviors which are the characteristics of non-Newtonian fluid behavior at high shear rate and boundary film formation on the solid surface. The consideration of elastic deformation in the contact region is also included in our computation and finally the converged film pressure and the film thickness with elastic deformation are obtained. The results are compared with those of Newtonian fluid model.

Interferences Between Work and NonWork In the Context of Smartwork: The Role of Boundary Strength and Autonomy

  • Yong-Young Kim;Sangjo Oh;Heejin Lee;Kyung Jin Cha
    • Asia pacific journal of information systems
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    • v.29 no.4
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    • pp.547-570
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    • 2019
  • With the advances of information technologies, the interest in SmartWork including extended version of telework and flexible work are increasing, and various types of SmartWork attempted to make working time and place flexible with the goal of work and life balance. Despite its emphasis on work and life balance, SmartWork is expected to make the boundaries between work and nonwork blur and role conflicts occur more than before, and thus the goal of work and life balance becomes more distant. A number of SmartWork users are significantly increasing in Korea, but little is known concerning the antecedents and mechanisms to explain psychological work and interferences in the SmartWork environment. In this paper, using boundary theory, we empirically investigate factors affecting the interferences at both work and nonwork domains. The results, based on data collected from SmartWork users in one of the biggest telecommunication companies in Korea where SmartWork is adopted and extensively used, suggest the factors may be affecting differently interferences at the work and nonwork domains.