C. Janna¹, M. Ferronato¹, G. Gambolati¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 239-244, 2008, DOI:10.3970/icces.2008.006.239

Abstract The geomechanical simulation of a faulted producing reservoir is a strongly non-linear problem due to the non-elastic behaviour of the depleted rocks and especially to the contact constraint prescribed on the fault surfaces. With penalty interface elements for the fault modeling the stiffness matrix may be severely ill-conditioned and the solution by the Preconditioned Conjugate Gradient requires the development and the implementation of ad hoc preconditioners. The present communication investigates the performance of a multilevel incomplete factorization aimed at enhancing convergence and reducing the computational cost of a non-linear geomechanical simulation. More >

M. Baldinger¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 233-238, 2008, DOI:10.3970/icces.2008.006.233

Abstract The aim of this paper is to demonstrate how the new highest technology can be used to develop and optimize the manufacturing plant. Based on the results of a preliminary study and other observations made during the last year, it was decided to bring a new technology in its factory. On the basis of climbing demand and the ever bigger nascent variety with the production of self loading wagons, the machine-factory is modernized by a mounting-street for self loading wagons. The use of RFID-technology, tied into an ERP-System, led to a clear optimization of the production-process. More >

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 area-excitation analysis than from point-excitation… More >

Daizhong Su¹, Wenjie Peng²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 221-228, 2008, DOI:10.3970/icces.2008.006.221

Abstract Finite element analysis (FEA) has proved to be a useful method to analyse the strength of worm gears; however, it is usually time consuming and difficult for parametric design, and, hence, it is difficult to apply FEA for design optimisation. To overcome this problem, artificial neural network and genetic algorithm are utilised in this research to optimise worm gear design based on FEA results. A new type of worm drive, an involute cylindrical worm matting with an involute helical gear, is taken as an vehicale to illustrate the approach developed. More >

A. M. Mughal¹, K. Iqbal²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 215-220, 2008, DOI:10.3970/icces.2008.006.215

Abstract Human voluntary movements are complex physical phenomenon and there are several physiological factors that control the movement and transient response, steady state position, speed of motion and other characteristics. Many experimentalists described variety of variables important for human balance and movement such as center of mass, center of pressure, ground reaction forces etc. In this study, we discuss a bipedal model for biomechanical sit to stand movement with optimal controller design. The cost optimization for gain scheduling is based upon physiological variables of center of mass, head position, and ground reaction forces. Our simulation results shows that movement profiles improve… More >

V.I. Alshits^1,2, R.K. Kotowski^1,3, P. Tronczyk¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 207-214, 2008, DOI:10.3970/icces.2008.006.207

Abstract The magnetoplastic effect manifests itself in a transformation of the structure of the impurity pinning centers in crystals exposed to an external magnetic field which modifies their mechanical properties. As a result, an ordinary nonmagnetic crystal becomes a smart material whose physical properties may be controlled by means of the external magnetic treatment. The basic features of this phenomenon and its established physical mechanisms are discussed. A series of results of experimental studies and computer simulations of the magnetoplastic effect are presented. More >

S. Lentzen¹, R. Schmidt¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.4, pp. 201-206, 2008, DOI:10.3970/icces.2008.006.201

Abstract In the present work the significance of considering geometrical nonlinearity in the application of piezoelectric materials in order to improve the dynamic and stability characteristics of thin structures is shown. For the numerical investigations a finite shell element has been used which employs strain displacement relations based on the first-order shear deformation moderate rotation theory. An ANS formulation has been used to overcome membrane and shear locking. Two numerical examples are shown. The first example deals with increasing the critical buckling load by incorporating piezoelectric layers into the structure. In the second example the nonlinear vibrations of a cantilevered beam… More >

I. Yoshida ¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 195-200, 2008, DOI:10.3970/icces.2008.006.195

Abstract A priori information is discussed in order to overcome the ill-posedness of damage detection. We compared Gauss and Laplace distributions to express the uncertainties of a priori information. Uncertainty level of a priori and observation information is related to the balance of a priori and observation terms in the objective function. Maximum likelihood method is used to determine the balance adaptively. The method is examined through numerical simulations of identification problem to detect damage of a bridge based on coupling vibration with moving vehicles. More >

Y. Shimamura¹, Y. Shibata², K. Tohgo³, H. Araki⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 189-194, 2008, DOI:10.3970/icces.2008.006.189

Abstract Polylactic acid (PLA) is a biodegradable plastic made from lactic acid, and can be produced by renewable raw materials. The mechanical properties of PLA are, however, not sufficient for structural materials. In our study, carbon nanofiber reinforced PLA was fabricated to overcome the deficiency of PLA and the mechanical properties were measured at room and elevated temperatures. Vapor grown carbon fiber (VGCF) was used for reinforcement. Three point bending specimens were fabricated by using injection molding, and then bending stiffness, bending strength and fracture toughness were measured for amorphous and crystallized specimens. As a result, it is shown that the… More >

A.Iwasaki¹, K.Yuguchi², A.Todoroki³, Y.Shimamura⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 183-188, 2008, DOI:10.3970/icces.2008.006.183

Abstract The present study is about study on the diagnostic accuracy of the unsupervised damage diagnosis method named SI-F method. For the health monitoring of existing structures, modeling of entire structure or obtaining data sets after creating damage for training is almost impossible. This raises significant demand for development of a low-cost diagnostic method that does not require modeling of entire structure or data on damaged structure. Therefore, the present study proposes a low-cost unsupervised statistical diagnostic method for structural damage detection. The proposed method statistically diagnoses structural condition by means of investigating the change of a response surface which conducts… More >