• Title/Summary/Keyword: structural parameter

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Optimization of a telescope movable support structure by means of Volumetric Displacements

  • Ortega, Nestor F.;Robles, Sandra I.
    • Structural Engineering and Mechanics
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    • v.31 no.4
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    • pp.393-405
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    • 2009
  • The Purpose of this paper is to show the applicability of a methodology, developed by the authors, with which to perform the mechanical optimization of space truss structures strongly restricted. This methodology use a parameter call "Volumetric Displacement", as the Objective Function of the optimization process. This parameter considers altogether the structure weight and deformation whose effects are opposed. The Finite Element Method is employed to calculate the stress/strain state and the natural frequency of the structure through a structural linear static and natural frequency analysis. In order to show the potentially of this simple methodology, its application on a large diameter telescope structure (10 m) considering the strongly restriction that became of its use, is presented. This methodology, applied in previous works on continuous structures, such as shell roof and fluid storage vessels, is applied in this case to a space truss structure, with the purpose of generalize its applicability to different structural topology. This technique could be useful in the morphology design of deployable and retractable roof structures, whose use has extensively spread in the last years.

Structural Response of Underground LNG Storage Tank (Parameter Study for Design Conditions) (지하식 LNG 저장탱크의 설계 조건에 따른 거동분석)

  • 곽효경;이광모;송종영
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.2
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    • pp.219-235
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    • 2002
  • This paper deals with parametric studies of the structural response of underground LNG storage tanks according to change in design conditions. In the design of underground LNG storage tank, it is requited to determine the optimal tank shape and dimension to represent a more improved structural behavior under many loading conditions and load combinations. Consequently, main factors which affect to the structural response of LNG storage tanks from planning and design up to maintenance, are investigated, and the differences in structural behavior due to those factors are analyzed. On the basis of the obtained results item parametric studies, a guideline for a more reasonable design is introduced.

Edge wave propagation in an Electro-Magneto-Thermoelastic homogeneous plate subjected to stress

  • Kakar, Rajneesh;Kakar, Shikha
    • Structural Engineering and Mechanics
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    • v.53 no.6
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    • pp.1201-1214
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    • 2015
  • This paper introduces the combined effect of electric field, magnetic field and thermal field on edge wave propagating in a homogeneous isotropic prestressed plate of finite thickness and infinite length. The dispersion relation of edge wave has been obtained by using classical dynamical theory of thermoelasticity. The phase velocity has been computed and shown graphically for various initial stress parameter, electro-magneto parameter, electric parameter and thermoelastic coupling parameter.

Influence of exterior joint effect on the inter-story pounding interaction of structures

  • Favvata, Maria J.;Karayannis, Chris G.;Liolios, Asterios A.
    • Structural Engineering and Mechanics
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    • v.33 no.2
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    • pp.113-136
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    • 2009
  • The seismic induced interaction between multistory structures with unequal story heights (inter-story pounding) is studied taking into account the local response of the exterior beam-column joints. Although several parameters that influence the structural pounding have been studied sofar, the role of the joints local inelastic behaviour has not been yet investigated in the literature as key parameter for the pounding problem. Moreover, the influence of the infill panels as an additional parameter for the local damage effect of the joints on the inter-story pounding phenomenon is examined. Thirty six interaction cases between a multistory frame structure and an adjacent shorter and stiffer structure are studied for two different seismic excitations. The results are focused: (a) on the local response of the critical external column of the multistory structure that suffers the hit from the slab of the adjacent shorter structure, and (b) on the local response of the exterior beam-column joints of the multistory structure. Results of this investigation demonstrate that the possible local inelastic response of the exterior joints may be in some cases beneficial for the seismic behaviour of the critical column that suffers the impact. However, in all the examined cases the developing demands for deformation of the exterior joints are substantially increased and severe damages can be observed due to the pounding effect. The presence of the masonry infill panels has also been proved as an important parameter for the response of the exterior beam-column joints and thus for the safety of the building. Nevertheless, in all the examined inter-story pounding cases the presence of the infills was not enough for the total amelioration of the excessive demands for shear and ductility of the column that suffers the impact.

Structural Change Analysis in a Real Interest Rate Model (실질금리 결정모형에서의 구조변화분석)

  • 전덕빈;박대근
    • Korean Management Science Review
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    • v.18 no.1
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    • pp.119-133
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    • 2001
  • It is important to find the equilibrium level of real interest rate for it affects real and financial sector of economy. However, it is difficult to find the equilibrium level because like the most macroeconomic model the real interest model has parameter instability problem caused by structural change and it is supported by various theories and definitions. Hence, in order to cover these problems structural change detection model of real interest rate is developed to combine the real interest rate equilibrium model and the procedure to detect structural change points. 3 equations are established to find various effects of other interest-related macroeconomic variables and from each equation, structural changes are found. Those structural change points are consistent with common expectation. Oil Crisis (December, 1987), the starting point of Economic Stabilization Policy (January, 1982), the starting point of capital liberalization (January, 1988), the starting and finishing points of Interest deregulation (January, 1992 and December, 1994), Foreign Exchange Crisis (December, 1977) are detected as important points. From the equation of fisher and real effects, real interest rate level is estimated as 4.09% (October, 1988) and dependent on the underlying model, it is estimated as 0%∼13.56% (October, 1988), so it varies so much. It is expected that this result is connected to the large scale simultaneous equations to detect the parameter instability in real time, so induces the flexible economic policies.

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A parameter calibration method for PFC simulation: Development and a case study of limestone

  • Xu, Z.H.;Wang, W.Y.;Lin, P.;Xiong, Y.;Liu, Z.Y.;He, S.J.
    • Geomechanics and Engineering
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    • v.22 no.1
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    • pp.97-108
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    • 2020
  • The time-consuming and less objectivity are the main problems of conventional micromechanical parameters calibration method of Particle Flow Code simulations. Thus this study aims to address these two limitation of the conventional "trial-and-error" method. A new calibration method for the linear parallel bond model (CM-LPBM) is proposed. First, numerical simulations are conducted based on the results of the uniaxial compression tests on limestone. The macroscopic response of the numerical model agrees well with the results of the uniaxial compression tests. To reduce the number of the independent micromechanical parameters, numerical simulations are then carried out. Based on the results of the orthogonal experiments and the multi-factor variance analysis, main micromechanical parameters affecting the macro parameters of rocks are proposed. The macro-micro parameter functions are ultimately established using multiple linear regression, and the iteration correction formulas of the micromechanical parameters are obtained. To further verify the validity of the proposed method, a case study is carried out. The error between the macro mechanical response and the numerical results is less than 5%. Hence the calibration method, i.e., the CM-LPBM, is reliable for obtaining the micromechanical parameters quickly and accurately, providing reference for the calibration of micromechanical parameters.

Development of Parameter-based 3D Object Generation System by Using Virtual Reality for Construction Project Design Phase (가상현실을 이용한 건설공사 설계단계의 파라미터기반 3D객체 생성체계 구축방안)

  • Kang, Leen-Seok;Kwon, Jung-Hui;Moon, Jin-Seok;Moon, Hyoun-Seok;Gi, Sang-Bok
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.108-113
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    • 2008
  • Virtual construction (VC) system enables project manager to visually check mistakes in design materials by using virtual reality technology. In using VC system, to make 3D object by each construction element is still tedious work. This study suggests an improved method to make 3D object by using parameter-based 3D generation function. The IDEFO model to organize the process for the function. A VC system by this function was developed in this study and the function was verified by a bridge project in this system.

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Structural Change and Stability in a Long-Run Parameter (장기모수의 구조변화와 안정성)

  • Kim, Tae-Ho
    • Communications for Statistical Applications and Methods
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    • v.18 no.4
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    • pp.495-505
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    • 2011
  • This study performs statistical tests for stability of a long-run relationship in the telecommunication market system by identifying the time path of a recursively estimated cointegration parameter. A dummy variable is used to recover stability for the period that the hypothesis of stable cointegration is rejected, and then a proper cointegrating relation is derived. A dummy variable appears to reflect the structural change in the cointegrating relation according to the analytical results for the error correction term.

Elastic Critical Load of Non-symmetrically Tapered Columns by Numerical Method (수치해석법에 의한 비대칭 변단면 기둥의 탄성 임계하중)

  • 신세욱;김선혜;이수곤
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.04a
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    • pp.11-18
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    • 1999
  • For the proper design of a slender compression member, the exact determination of the elastic critical load is crucial, In the cases of non-prismatic compression members, the determinations of the elastic critical load cannot be usually expressed in closed forms. h this paper, the non-symmetrically tapered compression members with arbitrary boundary conditions me analysed by using the finite element method to determine the elastic critical load. The main parameters considered in the numerical analysis are the In Parameter, $\alpha$ and the sectional property parameter, m. To generaliza the unmerical analysis, of the computed results for each sectional parameter, m are presented in algebraic equations, which agrees fairy well with those by F.E.M in most cases.

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