• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.32 no.2
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• pp.164-176
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• 1996

The main intention of this paper is to develop and compare the algorithm based on finite element procedures for nonlinear transient dynamic analysis which has combined effects of material and geometric nonlinearities. Incremental equilibrium equations based on the principle of virtual work are derived by the finite element approach. For the elasto - plastic large deformation analysis of shells and the determination of the displacement-time configuration under time-varying loads, the explicit, implicit and combined explicit-implicit time integration algorithm is adopted. In the time structure is selected and the results are compared with each others. Isoparametric 8-noded quadrilateral curved elements are used for shell structure in the analysis and for geometrically nonlinear elastic behaviour, a total Lagrangian coordinate system was adopted. On the other hands, material nonlinearity is based on elasto-plastic models with Von-Mises yield criteria. Thus, the combined explicit-implicit time integration algorithm is benefit in general case of shell structure, which is the result of this paper.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.217-222
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• 2015

In this paper, a study was conducted for the optimization through shear web of shape the Edison program in wind power blade. We measured the displacement and stress distribution through two optimization methods to select the model with the smallest displacement and stress values. Before running the analysis, We try to find the inflection point through the shear web of the model and then analyze by introducing the geometric nonlinearity. The first optimization variables are introduced by the pitch angle and three web shapes. Third model such a honeycomb structure is good way to get an advantage for bending test. According to a method of previous optimization, third model is chosen and then the thickness of the web and blade as a variable is introduced, it is extracted as a result of displacement and the maximum stress per mass.

• Wind and Structures
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• v.7 no.1
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• pp.55-70
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• 2004

Aerostatic instability of a suspension bridge may suddenly appears when the deformed shape of the structure produces an increase in the value of the three components of displacement-dependent wind loads distributed in the structure. This paper investigates the aerostatic stability of suspension bridges using an advanced nonlinear method based on the concept of limit point instability. Particular attention is devoted to aerostatic stability analysis of symmetrical suspension bridges. A long-span symmetrical suspension bridge (Hu Men Bridge) with a main span of 888 m is chosen for analysis. It is found that the initial configuration (symmetry or asymmetry) may affect the instability configuration of structure. A finite element software for the nonlinear aerostatic stability analysis of cable-supported bridges (NASAB) is presented and discussed. The aerostatic failure mechanism of suspension bridges is also explained by tracing aerostatic instability path.

• Smart Structures and Systems
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• v.18 no.1
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• pp.17-29
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• 2016

In this paper, the possibility of using human induced loading (HIL) to detect a decrease of tension in the cable-stays of an existing footbridge is investigated. First, a reliable finite elements model of an existing footbridge is developed by calibration with experimental data. Next, estimates of the tension in the cables are derived and their dependency on the modal features of the deck is investigated. The modelling of the HIL is briefly discussed and used to perform the nonlinear, large strain, dynamic finite elements analyses. The results of these analyses are assessed with focus on characterizing the time histories of the tension in the cables under pedestrian crossing and their effects on the deck response for different initial conditions. Finally, the control perspective is introduced in view of further research.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2002.10a
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• pp.287-294
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• 2002

An automatic design method of steel frames using nonlinear analysis is developed. The geometric nonlinearity is considered by the use of stability functions. A direct search method is used as an automatic design technique. The unit value of each member is evaluated by using LRFD Interaction equation. The member with the largest unit value Is replaced one by one with an adjacent larger member selected in the database. The weight of the steel frame is taken as an objective function. Load-carrying capacities, deflections, interstory drifts, and ductility requirement are used as constraint functions. Case study of a three-dimensional two story frame are presented.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.175-178
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• 2005

The major object of this paper is to propose a nonlinear finite element analysis(FEA) technique of steel coupling beams-wall connections governed panel shear failure using ABAQUS. Detailed finite element models are created by studying the monotonic load response of the designed steel coupling beams-wall connections. The developed models account for the effect of material inelasticity, concrete cracking, panel shear failure and geometric nonlinearity. In order to verify the proposed FEA model, this study attended experiment considered parameters to the steel beam : face bearing plates, and horizontal ties. And the analytical result attended by the proposed FEA model validated through comparisons with the experimental results. Finally, the study estimated the analytical values compared with ASCE Design Guidelines. At this time, the analysis showed good agreement between the theoretical and experimental results.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2003.10a
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• pp.285-292
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• 2003

The soft structure can make large space more effectively, and its construction is easy and simple as well. However, it is not easy to realize this in the actual space. Therefore, two works are needed to be done for effective and accurate construction of soft structures. First, making a working scenario to complete the final objective form; second revising construction errors occurred in the middle of the actual works. These works are called constructional analysis. At this time, geometric nonlinearity should be considered to reflect the sensitivity by the initial stress of flexible structures, constructional analysis comes down to a nonlinear problem after all. This study approaches nonlinear constructional analysis with the numerical method for adjusting stress of cable-dome structures which are a soft structure system, and then verifies it.

• Structural Engineering and Mechanics
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• v.15 no.4
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• pp.463-476
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• 2003

This paper deals with nonlinear asymmetric dynamic buckling of clamped laminated angle-ply composite spherical shells under suddenly applied pressure loads. The formulation is based on first-order shear deformation theory and Lagrange's equation of motion. The nonlinearity due to finite deformation of the shell considering von Karman's assumptions is included in the formulation. The buckling loads are obtained through dynamic response history using Newmark's numerical integration scheme coupled with a Newton-Raphson iteration technique. An axisymmetric curved shell element is used to investigate the dynamic characteristics of the spherical caps. The pressure value beyond which the maximum average displacement response shows significant growth rate in the time history of the shell structure is considered as critical dynamic load. Detailed numerical results are presented to highlight the influence of ply-angle, shell geometric parameter and asymmetric mode on the critical load of spherical caps.

• Structural Engineering and Mechanics
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• v.53 no.1
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• pp.131-146
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• 2015

In the present paper a three-dimensional non-linear truss element and a short computer program for the modeling and predicting approximate lateral deflections in thin glass plates by the method of incremental loading are proposed. Due to the out-of-plane large deflections of thin glass plates compared to the plate thickness within each loading increment, the equilibrium and stiffness conditions are written with respect to the deformed structure. An application is presented on a thin fully tempered monolithic rectangular glass plate, laterally supported around its perimeter subjected to uniform wind pressure. The results of the analysis are compared with published experimental results and found to have satisfactory approximation. It is also observed that the large deflections of a glass plate lead to a part substitution of the bending plate behavior by a tensioned membrane behavior which is favorable.

• Steel and Composite Structures
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• v.17 no.6
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• pp.867-890
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• 2014

This paper deals with the geometric nonlinear bending analysis of laminated composite stiffened plates subjected to uniform transverse loading. The eight-noded degenerated shell element and three-noded degenerated curved beam element with five degrees of freedom per node are adopted in the present analysis to model the plate and stiffeners respectively. The Green-Lagrange strain displacement relationship is adopted and the total Lagrangian approach is taken in the formulation. The convergence study of the present formulation is carried out first and the results are compared with the results published in the literature. The stiffener element is reformulated taking the torsional rigidity in an efficient manner. The effects of lamination angle, depth of stiffener and number of layers, on the bending response of the composite stiffened plates are considered and the results are discussed.