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  • Open Access


    Least Squares Stochastic Finite Element Method in Structural Stability Analysis of Steel Skeletal Structures1

    Marcin Kamiński2, Jacek Szafran3

    CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.1, pp. 27-57, 2015, DOI:10.3970/cmes.2015.107.027

    Abstract Basic probabilistic characteristics and reliability indices of critical forces for high steel skeletal towers are numerically modeled by using the Stochastic, perturbation-based Finite Element Method. It is implemented together with the Weighted Least Squares Method and compared with the Monte-Carlo simulation as well as with the semi-analytical Probabilistic FEM. The Finite Element Method solution to the stability problem for a full 3D model of a tower accounts for both first and second order effects known from the engineering codes as the so-called P-delta effect. Two different Gaussian input random variables are adopted here – Young modulus of steel as well… More >

  • Open Access


    Improved Failure Mode Identification and Reliability Estimates for Electricity Transmission Towers

    Xuwen An1,2, Jianguo Hou3, P.D. Gosling4, Dong Dai5, Long Xiao6, Xiaoyi Zhou7

    CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.1, pp. 1-25, 2015, DOI:10.3970/cmes.2015.107.001

    Abstract Studies on the theory of structural system reliability includes identification of main the failure modes and calculation of inclusive failure probabilities for the structural system. The efficient and accurate identification of failure modes in structural systems is difficult and represents a key focus for research in system reliability. The fundamental theory of the branch and bound algorithm for stage critical strength is reviewed in this paper. Some deficiencies in this method are highlighted. Corresponding approaches to overcome these deficiencies are proposed. Calculated system reliability solutions to the classical model, a truss with 10 elements, indicate that the improvement measures proposed… More >

  • Open Access


    Factorial Experiment Design in the Front Velocity Modeling Approach Applied to Chromatographic Separation of Glucose and Fructose

    A. Prieto-Moreno1, L.D.Tavares Câmara2, O. Llanes-Santiago1, A. J. Silva Neto2

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.6, pp. 441-462, 2015, DOI:10.3970/cmes.2015.106.441

    Abstract This work deals with a statistical approach to the uncertainty propagation analysis when estimating the kinetic mass transfer parameters used to model a chromatographic column in the Simulated Moving Bed. The chromatographic column modeling was performed using the new front velocity approach. The uncertainty propagation analysis of operational factors intervening in the chromatographic process to estimated parameters was made using the response surface methodology. The application of the factorial experimental design allowed us to establish those operational factors showing a greater influence on continuous chromatography. Besides, the chromatographic regions, where factors cause a greater output variation as well as their… More >

  • Open Access


    Assessment of Cell-centered and Cell-vertex Finite Volume Approaches for Computation of 2D Structural Dynamics on Arbitrary Quadrilateral Grids

    Kazem Hejranfar1, Mohammad-Hadi Azampour1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.6, pp. 395-439, 2015, DOI:10.3970/cmes.2015.106.395

    Abstract In this study, cell-centered (CC) and cell-vertex (CV) finite volume (FV) approaches are applied and assessed for the simulation of two-dimensional structural dynamics on arbitrary quadrilateral grids. For the calculation of boundary nodes’ displacement in the CC FV approach, three methods are employed. The first method is a simple linear regression of displacement of boundary nodes from the displacement of interior cell centers. In the second method, an extrapolation technique is applied for this purpose and, in the third method; the line boundary cell technique is incorporated into the solution algorithm in an explicit manner. To study the effects of… More >

  • Open Access


    Hybrid Adaptive Particle Swarm Optimized Particle Filter for Integrated Navigation System

    Zhimin Chen1,2, Yuanxin Qu1, Tongshuang Zhang1, Xiaoshu Bai1, Xiaohong Tao1, Yong Liu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.6, pp. 379-393, 2015, DOI:10.3970/cmes.2015.106.379

    Abstract Particle swarm optimization algorithm based particle filter is trapping in local optimum easily, it is not able to satisfy the requirement of modern integrated navigation system. In order to solve the problem, A novel particle filter algorithm based on hybrid adaptive particle swarm optimization(HPSO-PF) is presented in this paper. This improved particle filter will conduce to finding the ideal solution domain by making use of the global convergence of artificial fish swarm and enhancement of fusion precision by guiding particles to move toward the high likelihood area through particle swarm optimization. Finally different models are used for simulation and the… More >

  • Open Access


    Long Endurance and Long Distance Trajectory Optimization for Engineless UAV by Dynamic Soaring

    B. J. Zhu1,2, Z. X. Hou1, X. Z. Wang3, Q. Y. Chen1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 357-377, 2015, DOI:10.3970/cmes.2015.106.357

    Abstract The paper presents a comprehensive study on the performance of long endurance and long distance trajectory optimization of engineless UAV in dynamic soaring. A dynamic model of engineless UAV in gradient wind field is developed. Long endurance and long distance trajectory optimization problems are modelled by non-linear optimal control equations. Two different boundary conditions are considered and results are compared: (i) open long endurance pattern, (ii) closed long endurance pattern, (iii) open long distance pattern. In patterns of (i) and (ii), the UAV return to original position with the maximum flying time in pattern (ii) , and in patterns of… More >

  • Open Access


    Differing Mapping using Ensemble of Metamodels for Global Variable-fidelity Metamodeling

    Qi Zhou1, Xinyu Shao1, Ping Jiang1,2, Longchao Cao1, Hui Zhou1, Leshi Shu1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 323-355, 2015, DOI:10.3970/cmes.2015.106.323

    Abstract Computational simulation models with different fidelity have been widely used in complex systems design. However, running the most accurate simulation models tends to be very time-consuming and can therefore only be used sporadically, while incorporating less accurate, inexpensive models into the design process may result in inaccurate design alternatives. To make a trade-off between high accuracy and low expense, variable fidelity (VF) metamodeling approaches that aim to integrate information from both low fidelity (LF) and high-fidelity (HF) models have gained increasing popularity. In this paper, a Difference Mapping Framework using Ensemble of Metamodels (DMF-EM) for global VF metamodeling is proposed.… More >

  • Open Access


    Probability Density Transitions in the FitzHugh-Nagumo Model with Lévy Noise

    Xu Yong1,2, Feng Jing1, Xu Wei1, Gu Rencai1

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.5, pp. 309-322, 2015, DOI:10.3970/cmes.2015.106.309

    Abstract In this paper, bifurcation analysis and numerical simulations are performed on the FitzHugh-Nagumo system in the presence of Lévy stable noise. The stationary probability density functions are obtained to examine the influences of noise intensity and stability index. Results show that under the influences of noise intensity and stability index, the dynamic of the FitzHugh-Nagumo model can be well characterized through the concept of stochastic bifurcation, consisting in qualitative changes of the stationary probability distribution. Then, the mean passage time between the resting and action state is investigated as functions of noise intensity and stability index of the external signal… More >

  • Open Access


    Analytical Method for Simulation of Buckling and Post-buckling Behaviour of Curved Pates

    Joo Shin Park1, Jung Kwan Seo2,3

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.4, pp. 291-308, 2015, DOI:10.3970/cmes.2015.106.291

    Abstract Ships, ship-shaped offshore structures, land-based structures and aerospace structures typically consist of various curved plate components. It is difficult to simulate the buckling and post-buckling of curved thin and/or thick plates that have characteristics of nonlinear structural mechanics, such as nonlinear behaviour when loading is applied. The elastic post-buckling behaviour of a curved plate is very complex, and accompanied by mode changes due to the occurrence of secondary buckling behaviour. Therefore, it is very important to clarify the elastic post-buckling behaviour when subjected to axial loading. The aim of this study was to derive an analytical calculation based on the… More >

  • Open Access


    An Improved Technique to Generate RogueWaves in Random Sea

    Jinghua Wang1, S Yan1, Q.W. Ma1,2

    CMES-Computer Modeling in Engineering & Sciences, Vol.106, No.4, pp. 263-289, 2015, DOI:10.3970/cmes.2015.106.263

    Abstract This paper presents an improved technique to generate rogue (freak) waves embedded in random sea based on the approach proposed by Kribel and Alsina (2000). In this method, a part of the wave energy is focused using the temporal-spatial focusing approach to generate an extreme transient wave and the rest behaves randomly. By introducing a correction term, the improved technique removes the numerical.ly spurious fluctuations of the spectra in the existing approach. Various effects of the correction are investigated numerically by using the second-order wave theory and two existing numerical. methods based on the fully nonlinear potential theory (FNPT), including… More >

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