K. C. Liu¹, S. M. Arnold²

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 35-65, 2013, DOI:10.3970/cmc.2013.035.035

Abstract It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the influence of many of these scale specific architectural features of woven ceramic composite are examined stochastically at both the macroscale (woven repeating unit cell (RUC)) and structural More >

Taicong Chen¹, Haitao Ma¹, Wei Gao²

CMES-Computer Modeling in Engineering & Sciences, Vol.87, No.3, pp. 239-270, 2012, DOI:10.3970/cmes.2012.087.239

Abstract Monte Carlo simulation method has been used extensively in probabilistic analyses of engineering systems and its popularity has been growing. While it is widely accepted that the simulation results are asymptotically accurate when the number of samples increases, certain exceptions do exist. The major objectives of this study are to reveal the conditions of the applicability of Monte Carlo method and to provide new insights into the accuracy of the simulation results in stochastic structural analysis. Firstly, a simple problem of a spring with random axial stiffness subject to a deterministic tension is investigated, using… More >

James D.Turner, Manoranjan Majji, John L. Junkins

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.1, pp. 11-12, 2011, DOI:10.3970/icces.2011.016.011

Abstract Modeling uncertainty for nonlinear systems is often handled by developing a mathematical model, defining suitable parameters, establishing suitable initial conditions and numerically integrating the system response in order to study the behavior of the system. The potential range of behaviors that can be realized is assessed by varying the model parameters, integrating the response, and recording the changes in the system behaviors. In theory this process is straightforward for implementing. The only potential barrier to carrying out the repeated integrations of the system dynamics is the availability of powerful computer resources that can provide the… More >

C. Wang¹, W. Gao¹, C.W. Yang¹, C.M. Song¹

CMC-Computers, Materials & Continua, Vol.25, No.1, pp. 19-46, 2011, DOI:10.3970/cmc.2011.025.019

Abstract The random interval response and probabilistic interval reliability of structures with a mixture of random and interval properties are studied in this paper. Structural stiffness matrix is a random interval matrix if some structural parameters and loads are modeled as random variables and the others are considered as interval variables. The perturbation-based stochastic finite element method and random interval moment method are employed to develop the expressions for the mean value and standard deviation of random interval structural displacement and stress responses. The lower bound and upper bound of the mean value and standard deviation More >

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

CMC-Computers, Materials & Continua, Vol.24, No.3, pp. 183-208, 2011, DOI:10.3970/cmc.2011.024.183

Abstract The structural analysis of a particulate composite with randomly distributed hard spheres is presented based on a model proposed earlier. The structural factors considered include the distribution of interparticle distances and the conditions for particle agglomeration. The interparticle distance was characterized by the nearest particle distance (NPD) and the distance derived from Delaunay triangulation (DT). The distances were calculated for every particle in the particle set and analyzed in the form of a cumulative distribution function (CDF). The CDF provides two parameters: the representation of particles which are in very close proximity to their neighbors More >

C. R. A. Silva¹, H. P. Azikri de Deus¹, G.E. Mantovani², A.T. Beck³

CMES-Computer Modeling in Engineering & Sciences, Vol.67, No.2, pp. 119-150, 2010, DOI:10.3970/cmes.2010.067.119

Abstract In this paper, the Askey-Wiener scheme and the Galerkin method are used to obtain approximate solutions to stochastic beam bending on Winkler foundation. The study addresses Euler-Bernoulli beams with uncertainty in the bending stiffness modulus and in the stiffness of the foundation. Uncertainties are represented by parameterized stochastic processes. The random behavior of beam response is modeled using the Askey-Wiener scheme. One contribution of the paper is a sketch of proof of existence and uniqueness of the solution to problems involving fourth order operators applied to random fields. From the approximate Galerkin solution, expected value More >

J. Zidek¹ , J. Kucera¹, J. Jancar¹

CMC-Computers, Materials & Continua, Vol.16, No.1, pp. 51-74, 2010, DOI:10.3970/cmc.2010.016.051

Abstract It has been shown that in particulate filled composites, a cross-property relationship exists between various transport properties (e.g., electrical conductivity, mechanical reinforcement, gas permeation) of a macroscale composite. Thus, knowledge of the effective mechanical properties of a composite immediately places bounds on its electrical conductivity or gas permeation behavior. Using these bounds allows us to predict the phase dispersion state that optimizes one or multiple properties of the composite and, thus, the knowledge of how spatial arrangement of filler particles at their given content affects physical properties of the composite can be valuable. In this More >

M.A. Arafin, J.A. Szpunar

The International Conference on Computational & Experimental Engineering and Sciences, Vol.13, No.3, pp. 59-60, 2009, DOI:10.3970/icces.2009.013.059

Abstract This paper introduce a novel approach for face image segmentation base on Voronoi Diagram (VD) technique. We used intensity value and region pixels value for enhance preprocessing step on gray-scale image. The method for locating and extraction face/head boundary are applied feature point of the original image which are useful dual tessellation of the VD is know as Delaunay Triangulation (DT). A target of experiment is reported face image segmentation that uses still face image from BioID database. The result of this method clearly demonstrates the segmentation which performs in comparison with another method in More >

Sudib K. Mishra¹, J. K. Paik², S. N. Atluri¹

CMES-Computer Modeling in Engineering & Sciences, Vol.50, No.1, pp. 67-96, 2009, DOI:10.3970/cmes.2009.050.067

Abstract We present a simulation based study, by combining several models involving multiple time scales and physical processes, which govern the interfacial stress corrosion cracking (SCC) in grain boundaries, layered composites or bi-materials, and the mechanisms of inhibition using `smart' agents. The inhibiting agents described herein, automatically sense the initiation of damage, migrate to the sites and delay the corrosion kinetics involved in the process. The phenomenon of SCC is simulated using the lattice spring model (for the mechanical stresses), coupled with a finite difference model of diffusing species, causing the dissolution of the interfacial bonds.… More >

M.A.Arafin¹, J.A.Szpunar²

CMC-Computers, Materials & Continua, Vol.14, No.2, pp. 125-140, 2009, DOI:10.3970/cmc.2009.014.125

Abstract A novel microstructure, texture and grain boundary character based model has been proposed to simulate the intergranular crack propagation behavior in textured polycrystalline materials. The model utilizes the Voronoi algorithm and Monte Carlo simulations to construct the microstructure with desired grain shape factor, takes the texture description of the materials to assign the orientations of the grains, evaluates the grain boundary character based on the misorientation angle - axis calculated from the orientations of the neighboring grains, and takes into account the inclination of grain boundaries with respect to the external stress direction. Markov Chain More >