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A combined experimental and numerical method for structural response assessment applied to cable-stayed footbridges

  • Kossakowski, Pawel G.
    • Advances in Computational Design
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    • v.2 no.3
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    • pp.143-163
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    • 2017
  • This paper presents a non-destructive testing method for estimating the structural response of cable-stayed footbridges. The approach combines field measurements with a numerical static analysis of the structure. When the experimental information concerning the structure deformations is coupled with the numerical data on the structural response, it is possible to calculate the static forces and the design tension resistance in selected structural elements, and as a result, assess the condition of the entire structure. The paper discusses the method assumptions and provides an example of the use of the procedure to assess the load-carrying capacity of a real steel footbridge. The proposed method can be employed to assess cable-stayed structures including those made of other materials, e.g., concrete, timber or composites.

Genetic algorithms for balancing multiple variables in design practice

  • Kim, Bomin;Lee, Youngjin
    • Advances in Computational Design
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    • v.2 no.3
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    • pp.241-256
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    • 2017
  • This paper introduces the process for Multi-objective Optimization Framework (MOF) which mediates multiple conflicting design targets. Even though the extensive researches have shown the benefits of optimization in engineering and design disciplines, most optimizations have been limited to the performance-related targets or the single-objective optimization which seek optimum solution within one design parameter. In design practice, however, designers should consider the multiple parameters whose resultant purposes are conflicting. The MOF is a BIM-integrated and simulation-based parametric workflow capable of optimizing the configuration of building components by using performance and non-performance driven measure to satisfy requirements including build programs, climate-based daylighting, occupant's experience, construction cost and etc. The MOF will generate, evaluate all different possible configurations within the predefined each parameter, present the most optimized set of solution, and then feed BIM environment to minimize data loss across software platform. This paper illustrates how Multi-objective optimization methodology can be utilized in design practice by integrating advanced simulation, optimization algorithm and BIM.

Triangular units based method for simultaneous optimizations of planar trusses

  • Mortazavi, Ali;Togan, Vedat
    • Advances in Computational Design
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    • v.2 no.3
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    • pp.195-210
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    • 2017
  • Simultaneous optimization of trusses which concurrently takes into account design variables related to the size, shape and topology of the structure is recognized as highly complex optimization problems. In this class of optimization problems, it is possible to encounter several unstable mechanisms throughout the solution process. However, to obtain a feasible solution, these unstable mechanisms somehow should be rejected from the set of candidate solutions. This study proposes triangular unit based method (TUBM) instead of ground structure method, which is conventionally used in the topology optimization, to decrease the complexity of search space of simultaneous optimization of the planar truss structures. TUBM considers stability of the triangular units for 2 dimensional truss systems. In addition, integrated particle swarm optimizer (iPSO) strengthened with robust technique so called improved fly-back mechanism is employed as the optimizer tool to obtain the solution for these class of problems. The results obtained in this study show the applicability and efficiency of the TUBM combined with iPSO for the simultaneous optimization of planar truss structures.

Two rectangular elements based on analytical functions

  • Rezaiee-Pajand, Mohammad;Karimipour, Arash
    • Advances in Computational Design
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    • v.5 no.2
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    • pp.147-175
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    • 2020
  • To achieve appropriate stresses, two new rectangular elements are presented in this study. For reaching this aim, a complementary energy functional is used within an element for the analysis of plane problems. In this energy form, the Airy stress function will be used as a functional variable. Besides, some basic analytical solutions are found for the stress functions. These trial functions are matched with each element number of degrees of freedom, which leads to a number of equations with the anonymous constants. Subsequently, according to the principle of minimum complementary energy, the unknown constants can be expressed in terms of displacements. This system can be rewritten in terms of the nodal displacement. In this way, two new hybrid-rectangular triangular elements are formulated, which have 16 and 40 degrees of freedom. To validate the outcomes, extensive numerical studies are performed. All findings clearly demonstrate accuracies of structural displacements, as well as, stresses.

Finite element based modeling and thermal dynamic analysis of functionally graded graphene reinforced beams

  • Al-Maliki, Ammar F.H.;Ahmed, Ridha A.;Moustafa, Nader M.;Faleh, Nadhim M.
    • Advances in Computational Design
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    • v.5 no.2
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    • pp.177-193
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    • 2020
  • In the present research, dynamic analysis of functionally graded (FG) graphene-reinforced beams under thermal loading has been carried out based on finite element approach. The presented formulation is based on a higher order refined beam element accounting for shear deformations. The graphene-reinforced beam is exposed to transverse periodic mechanical loading. Graphene platelets have three types of dispersion within the structure including uniform-type, linear-type and nonlinear-type. Convergences and validation studies of derived results from finite element approach are also presented. This research shows that the resonance behavior of a nanocomposite beam can be controlled by the GPL content and dispersions. Therefore, it is showed that the dynamical deflections are notably influenced by GPL weight fractions, types of GPL distributions, temperature changes, elastic foundation and harmonic load excitation frequency.

Magneto-thermo-elastic response of exponentially graded piezoelectric hollow spheres

  • Allam, M.N.M.;Tantawy, R.;Zenkour, A.M.
    • Advances in Computational Design
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    • v.3 no.3
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    • pp.303-318
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    • 2018
  • This article presents a semi-analytical solution for an exponentially graded piezoelectric hollow sphere. The sphere interacts with electric displacement, elastic deformations, electric potentials, magneto-thermo-elasticity, and hygrothermal influences. The hollow sphere may be standing under both mechanical and electric potentials. Electro-magneto-elastic behavior of magnetic field vector can be described in the hollow sphere. All material, thermal and magnetic properties of hollow sphere are supposed to be graded in radial direction. A semi-analytical technique is improved to deduce all fields in which different boundary conditions for radial stress and electric potential are presented. Numerical examples for radial displacement, radial and hoop stresses, and electric potential are investigated. The influence of many parameters is studied. It is seen that the gradation of all material, thermal and magnetic properties has particular effectiveness in many applications of modern technology.

Properties and Anti-diabetic Effect of 7-O-p-Fluorobenzoylchrysin (7-O-파라플루오로벤조일크라이신의 물성 및 혈당강하효과)

  • 심상희;신준수;김명범;김화정;김원기;김성진;김박광
    • Biomolecules & Therapeutics
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    • v.6 no.3
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    • pp.256-260
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    • 1998
  • -7-o-p-Fluorobenzoylchrysin was synthesized by condensing p-flouorbenzoic acid with chrysin in organic solvent, and its structure was identified by NMR, MS, UV, and IR. We also investigated the physicochemical properties, hypoglycemic effect, and the quantitative analysis method of this compound. The correlation coefficient of calibration curve on this compound was approximately 0.9945 by absorption spectrophotometry and 0.9989 by high perfornance liqid chromatography 7-o-p-Fluorobenzoylchrysin was resolved in 6.014 min by reversed-phase HPLC column with solvents consisting of methanol (80%) and 10mM phosphoric acd. Its blood glucose inhibition rate is 20.7%.

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Effect of stiffened element and edge stiffener in strength and behaviour of cold formed steel built-up beams

  • Manikandan, P.;Sukumar, S.
    • Advances in Computational Design
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    • v.1 no.2
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    • pp.207-220
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    • 2016
  • The aim of this study is to investigate the effect of stiffened element and edge stiffener in the behaviour and flexural strength of built-up cold-formed steel beams. An experimental and analytical analysis of CFS channel sections in four different geometries is conducted, including simple channel sections, a stiffened channel section with or without edge stiffeners. Nonlinear finite element models are developed using finite element analysis software package ANSYS. The FEA results are verified with the experimental results. Further, the finite element model is used for parametric studies by varying the depth, thickness, and the effect of stiffened element, edge stiffener and their interaction with compression flanges on stiffened built-up cold-formed steel beams with upright edge stiffeners. In addition, the flexural strength predicted by the finite element analysis is compared with the design flexural strength calculated by using the North American Iron and Steel Institute Specifications for cold-formed steel structures (AISI: S100-2007) and suitable suggestion is made.

Seismic behavior of concrete gravity dams

  • Varughese, Jiji Anna;Nikithan, Sreelakshmi
    • Advances in Computational Design
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    • v.1 no.2
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    • pp.195-206
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    • 2016
  • Dams play a vital role in the development and sustainment in a country. Failure of dams leads to the catastrophic event with sudden release of water and is of great concern. Hence earthquake-resistant design of dams is of prime importance. The present study involves static, modal and transient analyses of dam-reservoir-foundation system using finite element software ANSYS 15. The dam and the foundation are modeled with 2D plane strain element "PLANE 42" and the reservoir by fluid acoustic element "FLUID 29" with proper consideration of fluid-structure interaction. An expression for the fundamental period of concrete dams is developed based on modal analysis. Seismic response of gravity dams subjected to earthquake acceleration is evaluated in terms of peak displacement and stress.

Increasing the performance of energy harvesting in vibration mode shapes

  • Jabbari, Majid;Ghayour, Mostafa;Mirdamadi, Hamid Reza
    • Advances in Computational Design
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    • v.1 no.2
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    • pp.155-173
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    • 2016
  • This paper presents a method of design for the energy harvesting of a piezoelectric cantilever beam. Vibration modes have strain nodes where the strain distribution changes in the direction of the beam length. Covering the strain nodes of the vibration modes with continuous electrodes effects a cancellation of the voltages outputs. The use of segmented electrodes avoids cancellations of the voltage for multi-mode vibration. The resistive load affects the voltage and generated power. The optimum resistive load is considered for segmented and continuous electrodes, and then the power output is verified. One of the effective parameters on energy harvesting performance is the existence of concentrated mass. This topic is studied in this paper. Resonance and off-resonance cases are considered for the harvester. In this paper, both theoretical and experimental methods are used for satisfactory results.