SAKO Fumiko¹, ADACHI Yukihiro¹, SHI Qinzhong², ANDO Shigemasa², TSUCHIHASHI Masahiro², HAGIWARA Ichiro³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 229-232, 2008, DOI:10.3970/icces.2008.006.229

Abstract Satellite equipment experience severe high random acoustic loads during launch phase. [1\hbox {}] Accurate prediction of this random vibration is demanded to prevent equipmtnt from trouble. In this paper, a new approach for vibro-acoustic coupling analysis is proposed to obtain more accurate prediction. The proposed method applies Mechanical Impedance Method to vibro-acoustic coupling analysis with FEM model of structure and SEA model of sound system. \newline The analysis of simple model is conducted to study the proposed method. The result from the comparison shows this method provides more accurate prediction with structure impedance calculated from More >

N.Ishizuka¹, T.Okada², T.Ikeno², K.Shiomi², M.Okuma³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.2, pp. 145-150, 2008, DOI:10.3970/icces.2008.006.145

Abstract The accurate modeling of structures is very important for any engineering analysis such as simulation and design optimization of mechanical systems for noise and vibration. It is desired that such a modeling process should not be time-consuming and that the created model must have structural dynamic properties corresponding with the actual ones. But in practice, it is often difficult or even impossible to satisfy the desire by using conventional theoretical methods such as the Finite Element Method (FEM) when we consider actual mechanical systems which consist of many substructures. In this paper, under the assumption… More >

Boštjan Brank¹, Adnan Ibrahimbegovic² and Uroš Bohinc³

CMES-Computer Modeling in Engineering & Sciences, Vol.33, No.1, pp. 85-108, 2008, DOI:10.3970/cmes.2008.033.085

Abstract In this work we study the accuracy of modern higher-order shell finite element formulations in computation of 3d stress state in elastic shells. In that sense we compare three higher-order shell models: (i) with seven displacement-like kinematic parameters, and (ii, iii) with six displacement-like kinematic parameters plus one strain-like kinematic parameter introduced by two different versions of enhanced assumed strain (EAS) concept. The finite element approximations of all shell models are based on 4-node quadrilateral elements. Geometrically nonlinear and consistently linearized forms of considered formulations are given. Several numerical examples are presented, where computed stresses More >

Adan Vega¹, Sherif Rashed², Yoshihiko Tango³, Morinobu Ishiyama³, Hidekazu Murakawa²

CMES-Computer Modeling in Engineering & Sciences, Vol.28, No.1, pp. 1-14, 2008, DOI:10.3970/cmes.2008.028.001

Abstract Experimental observations have shown that the inherent deformation produced by multi-heating lines is not a simple addition of the inherent deformation produced by single heating lines. Therefore, to accurately predict inherent deformation, the method of superposing inherent deformation of single heating lines is not appropriate. To overcome this difficulty, the authors investigate the influence of multi-heating lines on line heating inherent deformation. First, the influence of previous heating lines on inherent deformation of overlapping, parallel and crossing heating lines is clarified. The influence of the proximity to plate side edge on inherent deformation is also More >

C. Xu¹, X. Jia², R. A. Williams², E. H. Stitt³, M. Nijemeisland³, S. El-Bachir⁴, A. J. Sederman⁴, L. F. Gladden⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.23, No.2, pp. 117-126, 2008, DOI:10.3970/cmes.2008.023.117

Abstract Existing theories and computer models for packed columns are either incapable of handling complex pellet shapes or based on over-simplified packing geometry. A digital packing algorithm, namely DigiPac, has recently been developed to fill the gap. It is capable of packing of particles of any shapes and sizes in a container of arbitrary geometry, and is a first step towards a practical computational tool for reliable predictions of packed column properties based on the actual pellet shapes. DigiPac can operate in two modes: a Monte Carlo mode in which particles undergo directional diffusive motions; and… More >

W. Brocks¹, I. Scheider¹

Structural Durability & Health Monitoring, Vol.3, No.2, pp. 69-80, 2007, DOI:10.3970/sdhm.2007.003.069

Abstract Cohesive models are used for numerical crack extension analyses in order to predict the mechanical behavior of structures in cases of crack path bifurcation. Possible applications range from the macroscopic to the microscopic scale. As an example of applications to macroscopic engineering structures, simulations of a stiffened cylindrical shell under internal pressure are presented, where a skin crack may penetrate the rib or deviate. On the micro-scale, unit-cell calculation for a fiber-reinforced material is performed, where the fiber may debond or break. More >

K.G. Wang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.3, No.1, pp. 21-28, 2007, DOI:10.3970/icces.2007.003.021

Abstract A framework of applications of multiscale modeling to property prediction of advanced materials will be briefly presented. A methodology will be shown to link micro-scale to the continuum scale, integrating micro-scale modeling of microstructure with the large Thermo-Calc© database. This paradigm is successfully applied to the case of Fe-12Ni-6Mn maraging steel. We predict the mechanical properties of the maraging steel such as hardness. We found that our predictions in hardness is in agreement with experimental data. More >

Doo Kie Kim¹, Seong Kyu Chang¹, Sang Kil Chang¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.2, No.1, pp. 29-34, 2007, DOI:10.3970/icces.2007.002.029

Abstract Accurate and realistic strength estimation before the placement of concrete is highly desirable. In this study, the advanced probabilistic neural network (APNN) was proposed to reflect the global probability density function by summing the heterogeneous local probability density function automatically determined in the individual standard deviation of variables. Currently, the estimation of the compressive strength of concrete is performed by a probabilistic neural network (PNN) on the basis of concrete mix proportions, and the PNN is improved by the iteration method. However, an empirical method has been incorporated to specify the smoothing parameter in the More >

T. Fujimoto¹, T. Nishioka²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.4, pp. 133-138, 2007, DOI:10.3970/icces.2007.001.133

Abstract In this study, applicability of various fracture path prediction theories into dynamic elasto visco-plastic fracture is discussed by the moving finite element analyses. Outline of each fracture path theory and numerical method to predict fracture path are explained. Fracture path predictions are demonstrated in the numerical specimen model under mixed mode loading, and numerical results of fracture path prediction are compared. More >

Nishioka T.¹, Fujita N.¹, Fujimoto T.¹, Kogame M.¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.1, No.3, pp. 127-132, 2007, DOI:10.3970/icces.2007.001.127

Abstract In this study, numerical simulations of mixed-mode fracture paths in dynamic fracture phenomenon are carried out by using moving finite element method based on Delaunay automatic mesh generation. In addition, the experiments under same condition was carried out, and the both results were compared. The calculated paths by the simulation agree well with the fracture paths of the experiments. More >