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 >

J. Useche¹, P. Sollero², E.L. Albuquerque², L. Palermo³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 175-182, 2008, DOI:10.3970/icces.2008.006.175

Abstract The computational fracture analysis of cracked thick plates repaired with adhesively bonded composite patches using a boundary element formulation is presented. The shear deformable cracked isotropic plate was modeled using the Reissner's plate theory. In order to model the repair, a three parameter boundary element formulation, based on Kirchhoff's theory for symmetric layered composite plates was established. Interaction forces and moments between the cracked plate and the composite repair were modeled as distributed loads. Coupling equations, based on kinematic compatibility and equilibrium considerations for the adhesive layer, were established. In-plane shear-deformable model with transversal stiffness was considered in order to… More >

S. Kobayashi¹, J. Ji¹, H. Morikawa¹, D. Tang², D. N. Ku³

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 169-174, 2008, DOI:10.3970/icces.2008.006.169

Abstract The increase of the blood velocity in the distal side of the stenosis causes negative transmural pressure, and atheroscrerotic plaque is compressed, furthermore, the stenosis may cause the collpase which leads the rupture of the plaque. The resultant compression may be important in the development of atherosclerotic plaque fracture and subsequent thrombosis or distal embolization. We have developed stenosis models made of polyvinyl alcohol hydrogel, which closely approximate an arterial disease situation, and performed pulsatile flow experiments. Valsalva's maneuver and cough cause a sharp rise in jugular venous pressure to greater than 50 mmHg. Such transient pressure increases within the… More >

Mijia Yang¹, Qiao Pizhong²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.6, No.3, pp. 157-168, 2008, DOI:10.3970/icces.2008.006.157

Abstract A new fatigue model suitable for polymer matrix composites is proposed, based on dimensional analysis of testing and material variables involved in a fatigue test. The new model has a good physical and theoretical foundation based on progressive damage, and unifies all the material and testing parameters into one general equation. Especially, the model can be simplified to the Goodman relation or Gerber relation when capturing the effect of mean stresses. The model suggested can be used to substitute the classical S-N curves and reduce the testing number by 50{\%} required by ASTM standards. A series of experiments have also… More >