• Title/Summary/Keyword: Free faces

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Thermal stresses and deflections of functionally graded sandwich plates using a new refined hyperbolic shear deformation theory

  • Bouchafa, Ali;Bouiadjra, Mohamed Bachir;Houari, Mohammed Sid Ahmed;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.18 no.6
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    • pp.1493-1515
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    • 2015
  • A new refined hyperbolic shear deformation theory (RHSDT), which involves only four unknown functions as against five in case of other shear deformation theories, is presented for the thermoelastic bending analysis of functionally graded sandwich plates. Unlike any other theory, the number of unknown functions involved is only four, as against five in case of other shear deformation theories. The theory presented is variationally consistent, does not require shear correction factor, and gives rise to transverse shear stress variation such that the transverse shear stresses vary parabolically across the thickness satisfying shear stress free surface conditions. The sandwich plate faces are assumed to have isotropic, two-constituent material distribution through the thickness, and the modulus of elasticity, Poisson's ratio of the faces, and thermal expansion coefficients are assumed to vary according to a power law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic ceramic material. Several kinds of sandwich plates are used taking into account the symmetry of the plate and the thickness of each layer. The influences played by the transverse shear deformation, thermal load, plate aspect ratio and volume fraction distribution are studied. Numerical results for deflections and stresses of functionally graded metal-ceramic plates are investigated. It can be concluded that the proposed theory is accurate and simple in solving the thermoelastic bending behavior of functionally graded plates.

A new innovative 3-unknowns HSDT for buckling and free vibration of exponentially graded sandwich plates resting on elastic foundations under various boundary conditions

  • Rabhi, Mohamed;Benrahou, Kouider Halim;Kaci, Abdelhakim;Houari, Mohammed Sid Ahmed;Bourada, Fouad;Bousahla, Abdelmoumen Anis;Tounsi, Abdeldjebbar;Adda Bedia, E.A.;Mahmoud, S.R.;Tounsi, Abdelouahed
    • Geomechanics and Engineering
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    • v.22 no.2
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    • pp.119-132
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    • 2020
  • In this study a new innovative three unknowns trigonometric shear deformation theory is proposed for the buckling and vibration responses of exponentially graded sandwich plates resting on elastic mediums under various boundary conditions. The key feature of this theoretical formulation is that, in addition to considering shear deformation effect, it has only three unknowns in the displacement field as in the case of the classical plate theory (CPT), contrary to five as in the first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). Material characteristics of the sandwich plate faces are considered to vary within the thickness direction via an exponential law distribution as a function of the volume fractions of the constituents. Equations of motion are obtained by employing Hamilton's principle. Numerical results for buckling and free vibration analysis of exponentially graded sandwich plates under various boundary conditions are obtained and discussed. Verification studies confirmed that the present three -unknown shear deformation theory is comparable with higher-order shear deformation theories which contain a greater number of unknowns.

A Study on the Improvement of Surface Blasting Method in Pasir Coal Mine (파시르 탄광에서의 채탄발파공법에 대한 문제점 분석 및 개선방안 연구)

  • Choi Byung-Hee;Ryu Dong-Woo;SunWoo Choon
    • Explosives and Blasting
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    • v.24 no.1
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    • pp.57-62
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    • 2006
  • The typical blasting method adopted in Pasir Coal Mine is a surface blasting technique with a single free face. It means that there is only one free face, which is usually the ground surface. This kind of blasting method is easy to use but inevitably causes enormous ground vibrations, which, in turn, can affect the stability of the slopes comprising the various boundaries of the open pit mine. In addition, the method also has the problem of lowering the blast efficiency compared to other methods such as bench blasting methods or ones with more than two free faces. In this respect, a project was launched to develop a new blasting method that is suitable for controling the ground vibration and enhancing the blast efficiency. As a part of the project, authors investigated the current blasting method as well as the overall pit developing process in the mine, and established some important guidelines that should be observed during the whole development process. This paper presents the details of the typical blasting pattern and the pit developing method in the mine, and suggests the guidelines determined from the results of the observations.

Suhomlinsky's Theory on School Education (수호믈린스키의 학교교육론)

  • Paeng, Yeong-Il
    • Korean Journal of Comparative Education
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    • v.18 no.4
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    • pp.187-206
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    • 2008
  • The research examines the discussions on school education depicted in Suhomlinsky's works. After that, their implications upon our education are discussed. The results of this research are as follows: Suhomlinsky considered the enrichment of the learners mental life as a primary goal of education. Therefore, school education must ensure that children's learning be a part of their abundant mental life, and that it must contribute to the building of children's wisdom and their becoming a whole being as humans. In this perspective, Suhomlinsky emphasized the importance of education that enriches the mental life through reading books. He insists that education through reading books is a valuable course in lifelong education, and suggests specific ways to put it into practice. He points out the need for the students' liberty to think freely in schools, and claimed that providing students with breaks and free times is a way to obtain invaluable treasures. His experinences in educational practices may provide implications that will help solve the problems our education faces today.

The Betrayal of Love, Trauma Narrative and Subjectivity Formation: Toni Morrison's A Mercy (사랑의 배반, 트라우마 서사와 주체 형성 -토니 모리슨의 『자비』)

  • Koo, Eunsook
    • Journal of English Language & Literature
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    • v.57 no.5
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    • pp.813-838
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    • 2011
  • Toni Morrison's ninth novel A Mercy delves into the colonial American history of the seventeenth century when Europeans began to migrate to the New World and when the first slaves were brought to Virginia. Morrison presents a diverse group of people such as white Europeans, an American Indian, a free black man, indentured servants, and slaves from Africa in order to explore the subjects of ownership, freedom and racism. She emphasizes the fact that most of the Europeans who came to America in the early seventeenth century were the people who were thrown out from the society such as felons, prostitutes, servants and children. By portraying how these castaways tried to settle in a new environment surrounded by unknown dangers and challenges, Morrison demystifies and reconstructs the myth of the birth of America as a nation state. In continuation of Morrison's writings about love and the betrayal of love, her novel A Mercy explores the subjects of trauma, memory and subjectivity by choosing the topic of motherly love and its betrayal which she dealt with poignantly in Beloved. The female protagonist, Florens, is given away by her mother in partial payment of debt incurred by the owner of Florens's mother. The traumatic memory of Florens's separation from her mother shapes Florence's character. She has to revisit the site of the original traumatic experiences of being given up by her mother in order to reconstruct her fragmented memory and past. The recurring dream of the traumatic incident that takes hold of Florens can be explained by the trauma theory of Freud, Cathy Caruth, Suzette Henke, and Judith Herman. The paper explores the self journey of Florens in which she faces the traumatic past and comprehends its meaning which enables her to construct her subjectivity by understanding the true meaning of being free and of owning oneself. In particular, it demonstrates how the process of writing a confession, a story about one's history, enables one to reclaim the traumatic experience and to locate it in the narrative memory.

A Study of Fashion Design using Mondrian's Neo-Plasticism - Using Textile CAD System -

  • Row Young;Lee Youn-Hee
    • The International Journal of Costume Culture
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    • v.7 no.2
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    • pp.87-102
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    • 2004
  • By introducing Mondrian's creative world into the field of fashion design, I examined how its application can satisfy not only visual expressions but also the desire of fashion design for its simplicity, individuality, and sensitivity. As a program developing designs and guiding how to produce, the textile CAD system helps to develop a variety of textile systems. In case of dying or textile printing, a variety of free expressions of print patterns and functional color simulations are possible by the configuration of colors or enlargement of design. It can also confirm the flexible simulation with a variety of color changes through the monitor by treating the knit design with dots. Especially in case of consulting for the design with ordering customers, the system is very speedy and effective, because it is possible to correct on the spot those complicated elements of designs and color sensation and see the prints in the light of marketing, processing and artistic value. Mondrian's Art, beauty of balance and proportion in the Mondrian's plastic forms, the changes of coloring and texture were added into vertical and horizontal lines and the divisions of faces for the dressmaking. Whether they were the reciprocal action of human body, texture and color or the reciprocal action of human body and colors, these changes will be interpreted differently, depending on the individuals' experiences and psychological moods of situations. The emphases of the sense are also different, depending on the activity and functionality.

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Concept Selection of NPP Construction Delay Risk Assessment Methodology Using Systems Engineering Approach

  • Hossen, Muhammed Mufazzal;Kang, Sunkoo;Jung, JC;Kim, Jonghyun
    • Journal of the Korean Society of Systems Engineering
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    • v.11 no.1
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    • pp.9-24
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    • 2015
  • Construction industry faces a lot of inherent uncertainties and issues and the construction phase of nuclear power project is not free from this risk. This paper investigates promising methodologies to be used on nuclear power plant (NPP) construction schedule delay risk assessment by using entry level systems engineering approach. This study contains how the initial concept for the risk assessment methodology has been developed. In this point of view, this work structured on three main phases: needs analysis (NA), concept exploration (CE), and concept definition (CD) through systems engineering (SE) approach. Traditionally, the SE process is applied to technical development programs but this study opens up a new avenue that SE can also be successfully applied to the development and optimization of the risk assessment model. This study provides a rational and systematic process for developing and selecting the best risk assessment model. This paper selects analytic hierarchy process (AHP) method to assess NPP construction schedule delay risk for international project. As conclusion, the proposed concept and selected method can discriminate successfully and clearly among schedule delay risk assessment methods.

A Study of the Impacts on Electronic Distribution Industry after Korea-China FTA

  • Zhang, Ming-Lai;Lee, Sung-Joon
    • The Journal of Industrial Distribution & Business
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    • v.8 no.6
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    • pp.33-40
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    • 2017
  • Purpose - This study attempted to discover the impact of the Korea-China FTA(Free Trade Agreement) on electronic products distribution industry. Strategies will be provided to expand both countries' trade after the Korea-China FTA. Research design, data, and methodology - This study analyzed the differences before and after the Korea-China FTA, using an RCA(Revealed Comparative Advantage) index, TC(Technology Sophistication Index) index and TSI(Trade Specialization Index) that considered the FTA tariff situation. Data was collected from the International Trade Statistics Database and Korea, China Customs Service. Results - The results indicate that following the Korea-China FTA, China and Korea's bilateral trade of electronic products is expected to expand, and both countries will experience net welfare gains from the markets' expansion. Korea is competitive in several key products, although it faces competition from China. China's electronic products' competitiveness have indicated an increasing trend. Conclusions - The two countries should closely cooperate and communicate with each other. Ultimately, Korea should focus on high-tech, sophisticated techniques to gain market advantage. On the other hand, with the tariff decrease as well as the labor cost and labor force base, China will greatly be able to benefit from the manufacturing of medium- to low-end products in the future.

Finite element modeling and bending analysis of piezoelectric sandwich beam with debonded actuators

  • Rao, K. Venkata;Raja, S.;Munikenche, T.
    • Smart Structures and Systems
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    • v.13 no.1
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    • pp.55-80
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    • 2014
  • The present work pays emphasis on investigating the effect of different types of debonding on the bending behaviour of active sandwich beam, consisting of both extension and shear actuators. An active sandwich beam finite element is formulated by using Timoshenko's beam theory, characterized by first order shear deformation for the core and Euler-Bernoulli's beam theory for the top and bottom faces. The problem of debondings of extension actuator and face are dealt with by employing four-region model for inner debonding and three-region model for the edge debonding respectively. Displacement based continuity conditions are enforced at the interfaces of different regions using penalty method. Firstly, piezoelectric actuation of healthy sandwich beam is assessed through deflection analysis. Then the effect of actuators' debondings with different boundary conditions on bending behavior is computationally evaluated and experimentally clamped-free case is validated. The results generated will be useful to address the damage tolerant design procedures for smart sandwich beam structures with structural control and health monitoring applications.

Free vibration analysis of magneto-rheological smart annular three-layered plates subjected to magnetic field in viscoelastic medium

  • Amir, Saeed;Arshid, Ehsan;Maraghi, Zahra Khoddami
    • Smart Structures and Systems
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    • v.25 no.5
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    • pp.581-592
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    • 2020
  • Magneto-rheological fluids and magneto-strictive materials are of the well-known smart materials which are used to control and reduce the vibrations of the structures. Vibration analysis of a smart annular three-layered plate is provided in this work. MR fluids are used as the core's material type and the face sheets are made from MS materials and is assumed they are fully bonded to each other. The structure is rested on visco-Pasternak foundation and also is subjected to a transverse magnetic field. The governing motion equations are derived based on CPT and employing Hamilton's principle and are solved via GDQ as a numerical method for various boundary conditions. Effect of different parameters on the results are considered and discussed in detail. One of the salient features of this work is the consideration of MR fluids as the core, MS materials as the faces, and all of them under magnetic field. The outcomes of this study may be led to design and create smart structures such as sensors, actuators and also dampers.