J. Zidek^1,2, J. Kucera¹, J. Jancar^1,2

CMC-Computers, Materials & Continua, Vol.28, No.3, pp. 213-230, 2012, DOI:10.3970/cmc.2012.028.213

Abstract The paper presents a combination of worm-like chain numerical models and one with a finite set of nano-particles. The primary objective of the models was to analyze the distribution of space in a system filled by particles. Information on the distribution of space was compared to properties of chains inside the set of particles. The set of nanoparticles was constructed with a tool generating a finite set of particles that is randomly distributed in a given space. The particles have a prescribed volume fraction and uniform size. First, the proportions of chains and particles were… More >

Hsuan-Teh Hu¹, Jun-Ming Chen²

CMC-Computers, Materials & Continua, Vol.28, No.3, pp. 181-212, 2012, DOI:10.3970/cmc.2012.028.181

Abstract Free vibration analyses of laminated curved panels subjected to axial compressive forces are carried out by employing the Abaqus finite element program. The fundamental frequencies of these composite laminated curved panels with a given material system are then maximized with respect to fiber orientations by using the golden section method. Through a parametric study, the significant influences of the end conditions, the panel aspect ratio, the panel curvature and the compressive force on the maximum fundamental frequencies and the associated optimal fiber orientations are demonstrated and discussed. More >

C. Jiang^1,2, X. Han¹, D. Li³

CMC-Computers, Materials & Continua, Vol.27, No.3, pp. 275-304, 2012, DOI:10.3970/cmc.2011.027.275

Abstract For optimization or decision-making problems with interval uncertainty, the interval comparison relation plays a very important role, as only based on it a better or best decision can be determined. In this paper, a new kind of interval comparison relation termed as reliability-based possibility degree of interval is proposed to give quantitative evaluations on "how much better" of one interval than another, which is more suitable for engineering reliability analysis and numerical computation than the existing relations. In the new relation, the range of the comparing values is extended into the whole real number field, and the precise comparison More >

E. Ferretti¹, M.C. Bignozzi²

CMC-Computers, Materials & Continua, Vol.27, No.3, pp. 231-274, 2012, DOI:10.3970/cmc.2011.027.231

Abstract In this study, the results of an in-situ experimental program on the performance of concrete taxiways are presented. The experimental program has been undertaken at the Guglielmo Marconi airport of Bologna (Italy). It concerns two portions of the taxiway, one built with plain concrete and one with rubberized concrete. Each portion has been instrumented with strain gauges embedded in concrete for the acquisition of vertical strains. The results of the experimentation are discussed in view of possible applications to the computational analysis of the stress field induced into pavements by aircrafts. More >

A. Ramachandra Murthy¹, Nagesh R. Iyer¹, B.K. Raghu Prasad²

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.6, pp. 459-480, 2012, DOI:10.3970/cmes.2012.089.459

Abstract This paper presents the details of crack growth study and remaining life assessment of concrete specimens made up of high strength concrete (HSC, HSC1) and ultra high strength concrete (UHSC). Flexural fatigue tests have been conducted on HSC, HSC1 and UHSC beams under constant amplitude loading with a stress ratio of 0.2. It is observed from the studies that (i) the failure patterns of HSC1 and UHSC beams indicate their ductility as the member was intact till the crack propagated up to 90% of the beam depth and (ii) the remaining life decreases with increase… More >

Leiting Dong^1,2, Satya N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.5, pp. 417-458, 2012, DOI:10.3970/cmes.2012.089.417

Abstract Two-dimensional weakly-singular Symmetric Galerkin Boundary Elements (SGBEMs) are developed, following the work of [Han and Atluri (2003)], using non-hypersingular integral equations for tractions. Specifically, the present 2D SGBEM is used to compute the stress intensity factors for arbitrary-shaped line cracks, including embedded, edge, branching, and intersecting cracks. The computed stress intensity factors show high accuracy, even with very coarse meshes. The non-collinear mixed-mode fatigue growth analysis of cracks requires a very minimal effort¡ªsimply extending the cracks by adding an element to each crack tip, in the direction of the crack-growth as determined by a physics-based… More >

A.R.Ervilha^1,2, F.A.Sousa¹, J.M.C.Pereira¹, J.C.F.Pereira¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.5, pp. 361-387, 2012, DOI:10.3970/cmes.2012.089.361

Abstract Faster than real time stochastic fire spread predictions are reported using a Non-Intrusive Spectral Projection (NISP) method based on Polynomial Chaos expansion and Graphic Processing Units (GPUs). The fireLib BEHAVE model together with a raster surface fire growth algorithm was implemented using the Compute Unified Device Architecture (CUDA) programming language. The uncertainty generated by the four random variables considered (wind speed, wind direction, fuel moisture, and fuel load) is quantified in the stochastic solution. Stochastic simulation of an idealized vegetation fire in a realistic complex terrain is obtained with speed-ups as high as 176 when More >

Deli Gao¹, Feng Qian¹, Huikai Zheng¹

CMES-Computer Modeling in Engineering & Sciences, Vol.89, No.1, pp. 1-16, 2012, DOI:10.3970/cmes.2012.089.001

Abstract In deepwater wells for exploration and exploitation of oil & gas, the wellhead structure is of importance, and the annular pressure cannot be released after the casing hanger is set. The pressure changes in the casing annuli, caused by the temperature changes during the drilling and production processes, will increase the risk of failure of the casing. Therefore, a study of the safety of the casing in deepwater wells, by considering the complex engineering factors, will be of both academic as well as practical significance. In this paper, a model for the interactions among the… More >

Chih-Wen Chang^1,2, Chein-Shan Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.4, pp. 269-292, 2012, DOI:10.3970/cmes.2012.088.269

Abstract In this article, we utilize an optimal vector driven algorithm (OVDA) to cope with the nonlinear heat conduction problems (HCPs). From this set of nonlinear ordinary differential equations, we propose a purely iterative scheme and the spatial-discretization of finite difference method for revealing the solution vector x, without having to invert the Jacobian matrix D. Furthermore, we introduce three new ideas of bifurcation, attracting set and optimal combination, which are restrained by two parameters g and a. Several numerical instances of nonlinear systems under noise are examined, finding that the OVDA has a fast convergence More >

G. Trapani¹, T. Kipouros¹, A. M. Savill¹

CMES-Computer Modeling in Engineering & Sciences, Vol.88, No.2, pp. 107-140, 2012, DOI:10.3970/cmes.2012.088.107

Abstract This paper presents the development and the application of a multi-objective optimization framework for the design of two-dimensional multi-element high-lift airfoils. An innovative and efficient optimization algorithm, namely Multi-Objective Tabu Search (MOTS), has been selected as core of the framework. The flow-field around the multi-element configuration is simulated using the commercial computational fluid dynamics (cfd) suite Ansys cfx. Elements shape and deployment settings have been considered as design variables in the optimization of the Garteur A310 airfoil, as presented here. A validation and verification process of the cfd simulation for the Garteur airfoil is performed… More >