• Title/Summary/Keyword: variable foundation

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Parametric Studies of Flexural Free Vibrations of Circular Strip Foundations with Various End Constraints Resting on Pasternak Soil (경계조건 변화에 따른 Pasternak 지반으로 지지된 원호형 띠기초의 휨 자유진동에 관한 변수연구)

  • Lee, Byoung-Koo;Li, Guang-Fan;Kang, Hee-Jong;Yoon, Hee-Min
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.9
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    • pp.835-846
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    • 2007
  • This paper deals with the flexural free vibrations of circular strip foundation with the variable breadth on Pasternak soil. The breadth of strip varies with the linear functional fashion, which is symmetric about the mid-arc. Differential equations governing flexural free vibrations of such strip foundation are derived, in which the elastic soil with the shear layer, i.e. Pasternak soil, is considered. Effects of the rotatory and shear deformation are included in the governing equations. Differential equations are numerically solved to calculate the natural frequencies and mode shapes. In the numerical examples, the hinged-hinged, hinged-clamped and clamped-clamped end constraints are considered. Four lowest frequency parameters accompanied with their corresponding mode shapes are reported and parametric studies between frequency parameters and various system parameters are investigated.

A Study on the Face Image to Color of Make-up (색채 메이크업에 의한 얼굴이미지 연구)

  • Song, Mi-Young;Park, Oak-Reon;Ha, Jong-Kyung
    • Fashion & Textile Research Journal
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    • v.7 no.5
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    • pp.527-534
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    • 2005
  • The purpose of this research is to study face images according to color of make-up was made by computer graphic simulation. The various facial images can be helpful for choosing suitable make-up color planning. In order to find out the differences of face images by make-up color, three different foundations and seven eye-shadows, six lips were applied on the round face model. Make-up Image Scale was used the scale of seven point modified the S-D method. Data were analyzed by Varimax perpendicular rotation method, Duncan's Multiple Range Test, Three-way ANOVA. As the result of make-up image perception analysis, a factor structure was divided into mildness, modernness, elegance, unique. The factor of mildness, modernness, unique affected on the foundation color. Foundation color was found out to be influential variable to distinguish color perception abilities. Also, the foundation, eye-shadow, lip color were influenced interactively on the perception of elegance factor. Pink color was important color, influenced on the mildness factor. Gray and purple color were influenced on the modernness factor. Mildness factor was perceived as the most bright foundation but unique factor was perceived as the most dark foundation. Then, the foundation, eye-shadow, lip color were influenced interactively on the perception of facial images. The results can be effectively applied to today's marketing and color design management which is focused on the product's emotional image in customer's mind.

The Effect of Green Foundation on the Visual Preference (시각적 선호에 있어서 Green Foundation의 효과에 관한 연구)

  • 조동범;염도의
    • Journal of the Korean Institute of Landscape Architecture
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    • v.13 no.1
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    • pp.95-107
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    • 1985
  • This study is purposed to investigate the role of grasses as the Green Foundation effect on the visual preference to flowering tree and shrub being the principal elements of natural landscape early in the spring. As the flowering shrub materials, Rhododendron mucronulatum and Forsythia Kreana were adopted. Total 48 slides were photographed at the 8 different lawn areas with the 6 planting combinations of flowering shrub materials, and 10 landscape variables - dimensional and color - were measured and preference scores were taken by slide evaluations. The results were : 1) The visual preference to the landscape of flowering shrub in the lawn area was changed with the different lawn situations. 2) With important 4 variables, multilinear regression model was established, hence Y =40.4 + 9.6($X_1$) -7.8($X_2$) -26.8($X_3$) + 15.2($X_4$) where, Y : estimated preference score $X_1$: perimeter of flower zone $X_2$: value of green covered zone $X_3$: hue of green covered zone $X_4$: chroma of green covered zone 3) Most effective variable was 'hue of green covered zone', hence the more green the lawn area ism the more preferred landscape or the more effective green foundation is.

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Mathematical formulations for static behavior of bi-directional FG porous plates rested on elastic foundation including middle/neutral-surfaces

  • Amr E. Assie;Salwa A. Mohamed;Alaa A. Abdelrahman;Mohamed A. Eltaher
    • Steel and Composite Structures
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    • v.48 no.2
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    • pp.113-130
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    • 2023
  • The present manuscript aims to investigate the deviation between the middle surface (MS) and neutral surface (NS) formulations on the static response of bi-directionally functionally graded (BDFG) porous plate. The higher order shear deformation plate theory with a four variable is exploited to define the displacement field of BDFG plate. The displacement field variables based on both NS and on MS are presented in detail. These relations tend to get and derive a new set of boundary conditions (BCs). The porosity distribution is portrayed by cosine function including three different configurations, center, bottom, and top distributions. The elastic foundation including shear and normal stiffnesses by Winkler-Pasternak model is included. The equilibrium equations based on MS and NS are derived by using Hamilton's principles and expressed by variable coefficient partial differential equations. The numerical differential quadrature method (DQM) is adopted to solve the derived partial differential equations with variable coefficient. Rigidities coefficients and stress resultants for both MS and NS formulations are derived. The mathematical formulation is proved with previous published work. Additional numerical and parametric results are developed to present the influences of modified boundary conditions, NS and MS formulations, gradation parameters, elastic foundations coefficients, porosity type and porosity coefficient on the static response of BDFG porous plate. The following model can be used in design and analysis of BDFG structure used in aerospace, vehicle, dental, bio-structure, civil and nuclear structures.

Modeling wave propagation in graphene sheets influenced by magnetic field via a refined trigonometric two-variable plate theory

  • Fardshad, R. Ebrahimi;Mohammadi, Y.;Ebrahimi, F.
    • Structural Engineering and Mechanics
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    • v.72 no.3
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    • pp.329-338
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    • 2019
  • In this paper, the magnetic field influence on the wave propagation characteristics of graphene nanosheets is examined within the frame work of a two-variable plate theory. The small-scale effect is taken into consideration based on the nonlocal strain gradient theory. For more accurate analysis of graphene sheets, the proposed theory contains two scale parameters related to the nonlocal and strain gradient effects. A derivation of the differential equation is conducted, employing extended principle of Hamilton and solved my means of analytical solution. A refined trigonometric two-variable plate theory is employed in Kinematic relations. The scattering relation of wave propagation in solid bodies which captures the relation of wave number and the resultant frequency is also investigated. According to the numerical results, it is revealed that the proposed modeling can provide accurate wave dispersion results of the graphene nanosheets as compared to some cases in the literature. It is shown that the wave dispersion characteristics of graphene sheets are influenced by magnetic field, elastic foundation and nonlocal parameters. Numerical results are presented to serve as benchmarks for future analyses of graphene nanosheets.

A Meta-Analysis of the Variables Related with Social Support for Female Marriage Immigrants (여성결혼이민자의 사회적 지지와 관련 변인 메타분석)

  • Lee, Eun-Joo;Jun, Mi-Kyung
    • Journal of Families and Better Life
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    • v.31 no.5
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    • pp.125-141
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    • 2013
  • This research aims to integrate study results through a meta-analysis of previous studies on the variables related with social support for female marriage immigrants. Based on the results, this study established the foundation of an integrated social support system for female marriage immigrants which considers both the functional perspective and structural perspective of social support, and suggested plans for an efficient support system. All social support was positively associated with female marriage immigrants marriage life, child-rearing behavior and attitude, reduction of stress and depression and psychological stability. In relation to the effect size of each variable related with all social support, the marriage variable had the biggest relationship with it, followed by the parenting variable, the psychological variable and the stress variable in that order. With reference to the relationship with related variables according to the sub-domain of social support, from the structural perspective, spousale support showed a high relationship with the marriage variable and the stress variable. It was also especially, very highly related with the marriage variable. In addition, a married woman's family support and expert support had an intermediate relationship with the marriage variable, and the husband's family support and friend support had a low relationship with it. From the functional perspective, material support had a very high relationship with the marriage variable, whereas it had a low relationship with the stress variable and the psychological variable. Emotional support was also highly related with marriage variable, but showed an intermediate or low relationship with the psychological variable and the stress variable. On the other hand, informational support displayed an intermediate relationship with the stress variable and the psychological variable, and a high relationship with the marriage variable. Lastly, evaluative support had a high relationship with the marriage variable and the psychological variable. Based on these results, this study proposed plans for an integrated social support system as follows. First, education ought to be provided for the spouses, and support for marital adjustment should be offered. Second, there plans should be made for continuous bonding with the family of origin, and support should be given to address changes in awareness of the relationship with the husband's parents. Third, it is required to revitalize the local community and self-help groups, and provide the female marriage immigrants with opportunities to participate in social activities.

Contact buckling behaviour of corrugated plates subjected to linearly varying in-plane loads

  • Dong, Jianghui;Ma, Xing;Zhuge, Yan;Mills, Julie E.
    • Steel and Composite Structures
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    • v.29 no.3
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    • pp.333-348
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    • 2018
  • An analytical method is developed for analysing the contact buckling response of infinitely long, thin corrugated plates and flat plates restrained by a Winkler tensionless foundation and subjected to linearly varying in-plane loadings, where the corrugated plates are modelled as orthotropic plates and the flat plates are modelled as isotropic plates. The critical step in the presented method is the explicit expression for the lateral buckling mode function, which is derived through using the energy method. Simply supported and clamped edges conditions on the unloaded edges are considered in this study. The acquired lateral deflection function is applied to the governing buckling equations to eliminate the lateral variable. Considering the boundary conditions and continuity conditions at the border line between the contact and non-contact zones, the buckling coefficients and the corresponding buckling modes are found. The analytical solution to the buckling coefficients is also expressed through a fitted approximate formula in terms of foundation stiffness, which is verified through previous studies and finite element (FE) method.

Free vibration analysis of embedded nanosize FG plates using a new nonlocal trigonometric shear deformation theory

  • Besseghier, Abderrahmane;Houari, Mohammed Sid Ahmed;Tounsi, Abdelouahed;Mahmoud, S.R.
    • Smart Structures and Systems
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    • v.19 no.6
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    • pp.601-614
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    • 2017
  • In this work, free vibration analysis of size-dependent functionally graded (FG) nanoplates resting on two-parameter elastic foundation is investigated based on a novel nonlocal refined trigonometric shear deformation theory for the first time. This theory includes undetermined integral variables and contains only four unknowns, with is even less than the conventional first shear deformation theory (FSDT). Mori-Tanaka model is employed to describe gradually distribution of material properties along the plate thickness. Size-dependency of nanosize FG plate is captured via the nonlocal elasticity theory of Eringen. By implementing Hamilton's principle the equations of motion are obtained for a refined four-variable shear deformation plate theory and then solved analytically. To show the accuracy of the present theory, our research results in specific cases are compared with available results in the literature and a good agreement will be demonstrated. Finally, the influence of various parameters such as nonlocal parameter, power law indexes, elastic foundation parameters, aspect ratio, and the thickness ratio on the non-dimensional frequency of rectangular FG nanoscale plates are presented and discussed in detail.

The Optimization of Truss Structures with Genetic Algorithms

  • Wu, Houxiao;Luan, Xiaodong;Mu, Zaigen
    • Journal of Korean Association for Spatial Structures
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    • v.5 no.3 s.17
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    • pp.117-122
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    • 2005
  • This paper investigated the optimum design of truss structures based on Genetic Algorithms (GA's). With GA's characteristic of running side by side, the overall optimization and feasible operation, the optimum design model of truss structures was established. Elite models were used to assure that the best units of the previous generation had access to the evolution of current generation. Using of non-uniformity mutation brought the obvious mutation at earlier stage and stable mutation in the later stage; this benefited the convergence of units to the best result. In addition, to avoid GA's drawback of converging to local optimization easily, by the limit value of each variable was changed respectively and the genetic operation was performed two times, so the program could work more efficiently and obtained more precise results. Finally, by simulating evolution process of nature biology of a kind self-organize, self-organize, artificial intelligence, this paper established continuous structural optimization model for ten bars cantilever truss, and obtained satisfactory result of optimum design. This paper further explained that structural optimization is practicable with GA's, and provided the theoretic basis for the GA's optimum design of structural engineering.

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A four variable refined nth-order shear deformation theory for mechanical and thermal buckling analysis of functionally graded plates

  • Fahsi, Asmaa;Tounsi, Abdelouahed;Hebali, Habib;Chikh, Abdelbaki;Adda Bedia, E.A.;Mahmoud, S.R.
    • Geomechanics and Engineering
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    • v.13 no.3
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    • pp.385-410
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    • 2017
  • This work presents a simple and refined nth-order shear deformation theory for mechanical and thermal buckling behaviors of functionally graded (FG) plates resting on elastic foundation. The proposed refined nth-order shear deformation theory has a new displacement field which includes undetermined integral terms and contains only four unknowns. Governing equations are obtained from the principle of minimum total potential energy. A Navier type analytical solution methodology is also presented for simply supported FG plates resting on elastic foundation which predicts accurate solution. The accuracy of the present model is checked by comparing the computed results with those obtained by classical plate theory (CPT), first-order shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). Moreover, results demonstrate that the proposed theory can achieve the same accuracy of the existing HSDTs which have more number of variables.