C. Frueh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.2, pp. 171-201, 2016, DOI:10.3970/cmes.2016.111.171

Abstract In recent years, probabilistic tracking methods have been becoming increasingly popular for solving the multi-target tracking problem in Space Situational Awareness (SSA). Bayesian frameworks have been used to describe the objects' of interest states and cardinality as point processes. The inputs of the Bayesian framework filters are a probabilistic description of the scene at hand, the probability of clutter during the observation, the probability of detection of the objects, the probability of object survival and birth rates, and in the state update, the measurement uncertainty and process noise for the propagation. However, in the filter derivation, the assumptions of Poisson… More >

Xiaoli Bai¹, John L. Junkins²

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.2, pp. 129-146, 2016, DOI:10.3970/cmes.2016.111.129

Abstract This paper presents Modified Chebyshev-Picard Iteration (MCPI) methods for long-term integration of the coupled orbit and attitude dynamics. Although most orbit predictions for operational satellites have assumed that the attitude dynamics is decoupled from the orbit dynamics, the fully coupled dynamics is required for the solutions of uncontrolled space debris and space objects with high area-to-mass ratio, for which cross sectional area is constantly changing leading to significant change on the solar radiation pressure and atmospheric drag. MCPI is a set of methods for solution of initial value problems and boundary value problems. The methods refine an orthogonal function approximation… More >

J.L. Read¹, A. Bani Younes², J.L. Junkins³

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.1, pp. 65-81, 2016, DOI:10.3970/cmes.2016.111.065

Abstract This paper focuses on propagating perturbed two-body motion using orbital elements combined with a novel integration technique. While previous studies show that Modified Chebyshev Picard Iteration (MCPI) is a powerful tool used to propagate position and velocity, the present results show that using orbital elements to propagate the state vector reduces the number of MCPI iterations and nodes required, which is especially useful for reducing the computation time when including computationally-intensive calculations such as Spherical Harmonic gravity, and it also converges for > 5.5x as many revolutions using a single segment when compared with cartesian propagation. Results for the Classical… More >

B. Macomber¹, A. B. Probe¹, R. Woollands¹, J. Read¹, J. L. Junkins¹

CMES-Computer Modeling in Engineering & Sciences, Vol.111, No.1, pp. 29-64, 2016, DOI:10.3970/cmes.2016.111.029

Abstract Modified Chebyshev Picard Iteration is an iterative numerical method for solving linear or non-linear ordinary differential equations. In a serial computational environment the method has been shown to compete with, or outperform, current state of practice numerical integrators. This paper presents several improvements to the basic method, designed to further increase the computational efficiency of solving the equations of perturbed orbit propagation. More >

U. Hanoglu¹, B. Šarler^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.5, pp. 447-479, 2015, DOI:10.3970/cmes.2015.109.447

Abstract The aim of this paper is to demonstrate the use of the novel Local Radial Basis Function Collocation Method (LRBFCM) [Šarler and Vertnik (2006)] in an industrial coupled thermo-mechanical problem of hot shape rolling of steel. The physical concept of such a large deformation problem is based on a two dimensional traveling slice model [Glowacki (2005)], which assumes deformation and heat flow only in the perpendicular direction to rolling. The solution is performed based on strong formulation. Elliptic Node Generation (ENG) is applied to reposition the nodes over a slice when necessary in order to sustain stability throughout the simulation.… More >

Mohammad Ilati¹, Mehdi Dehghan²

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.4, pp. 325-360, 2015, DOI:10.3970/cmes.2015.109.325

Abstract In this paper, at first, a new combined shape function is proposed. Then, based on this shape function, the meshless local weak form method is applied to find the numerical solution of time-dependent non-linear Brusselator and Gierer- Meinhardt systems. The combined shape function inherits the properties of radial point interpolation (RPI), moving least squares (MLS) and moving Kriging (MK) shape functions and is controlled by control parameters, which take different values in the domain [0;1]. The combined shape function provides synchronic use of different shape functions and this leads to more flexibility in the used method. The main aim of… More >

Chung-Fu Chen¹, Yi-Chia Cheng¹, Che-Wun Hong^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.109-110, No.3, pp. 263-283, 2015, DOI:10.3970/cmes.2015.109.263

Abstract Based on the Hellmann-Feynman theorem, which integrates the molecular dynamics simulation with computational quantum mechanics, this research simulates the ionic transport in the LiCl-KCl molten salt materials using so called “first principles molecular dynamics (FPMD)” technique without employing an empirical potential model. The main purpose of this computational FPMD focuses on the evaluation of important transport properties, such as diffusion coefficient, ionic conductivity, shear viscosity, and thermal conductivity, using the Green-Kubo relationship. All simulation results agree well with experimental data published in existing literatures within an acceptable range. FPMD calculations are proved to be a powerful tool for prediction of… More >

Jun Huang^1,2, Chaopu Zhang¹, Song Xiang², Liu Yang¹, Mingxu Yi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.5, pp. 315-330, 2015, DOI:10.3970/cmes.2015.108.315

Abstract In order to accurately predict the aerodynamic noise of the propeller, a hybrid method combining Computational Fluid Dynamics (CFD) method with Boundary Element Method (BEM) is developed in this paper. The calculation includes two steps: firstly, the unsteady viscous flow around the propeller is calculated using the CFD method to acquire the noise source information; secondly, the radiated sound pressure is calculated using BEM method in the frequency domain. In comparison with the experimental results from wind tunnel, the calculated results of aerodynamic performance are rather desirable. The simulation and experimental results of aerodynamic noise are well fitted. The directivity… More >

Surkay D. Akbarov^1,2,3, Panakh G. Panakhlı⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.2, pp. 89-112, 2015, DOI:10.3970/cmes.2015.108.089

Abstract The discrete-analytical solution method is proposed for the solution to problems related to the dynamics of the hydro-elastic system consisting of an axially-moving pre-stressed plate, compressible viscous fluid and rigid wall. The fluid flow caused by the axial movement of the plate and the pre-stresses in the plate are taken into consideration as the initial state of the system under consideration. It is assumed that the additional lineally-located time-harmonic forces act on the plate and these forces cause additional flow field in the fluid and an additional stress-strain state in the plate. The additional stress-strain state in the plate is… More >

Isa Ahmadi¹, M.M. Aghdam²

CMES-Computer Modeling in Engineering & Sciences, Vol.108, No.1, pp. 21-48, 2015, DOI:10.3970/cmes.2015.108.021

Abstract In this study, a truly meshless method based on the meshless local Petrov-Galerkin method is formulated for analysis of the elastic-plastic behavior of heterogeneous solid materials. The incremental theory of plasticity is employed for modeling the nonlinearity of the material behavior due to plastic strains. The well-known Prandtl-Reuss flow rule of plasticity is used as the constitutive equation of the material. In the presented method, the computational cost is reduced due to elimination of the domain integration from the formulation. As a practical example, the presented elastic-plastic meshless formulation is employed for micromechanical analysis of the unidirectional composite material. A… More >