Zhiyu Guo*, Yuting Wu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.3, pp. 161-164, 2019, DOI:10.32604/icces.2019.05490

Abstract Generally, the greater the difference between evaporation and condensation temperature of ORC(Organic Rankie Cycle) is, the higher system efficiency and the larger expansion ratio will be [1,2]. Fig. 1 shows that net efficiency of theoretical cycle and expansion ratio of ORC system changes with evaporation temperature when condensing temperature is 313 K (R123 and HFO-1336mzz (Z) are selected). More >

Yoshihiro Ochiai¹, Vladimir Sladek²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.6, pp. 525-536, 2004, DOI:10.3970/cmes.2004.006.525

Abstract The conventional boundary element method (BEM) uses internal cells for the domain integralsCwhen solving nonlinear problems or problems with domain effects. This paper is concerned with conversion of the domain integral into boundary ones and some non-integral terms in a three-dimensional BIEM, which does not require the use of internal cells. This method uses arbitrary internal points instead of internal cells. The method is based on a three-dimensional interpolation method in this paper by using a polyharmonic function with volume distribution. In view of this interpolation method, the three-dimensional numerical integration is replaced by boundary ones and preceding calculation of… More >

Changqing Miao¹, Yintao Wei², Xiangqiao Yan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.6, pp. 519-534, 2013, DOI:10.3970/cmes.2013.095.519

Abstract By using a hybrid displacement discontinuity method, the interactions of three parallel square-hole cracks in an infinite plate subjected to internal pressure are investigated in this paper. Numerical examples are included to illustrate that the numerical approach is very simple and effective for calculating the stress intensity factors (SIFs) of complex plane crack problems. Many numerical results of the SIFs are given and discussed. It is found that a square hole has a shielding effect on crack(s) emanating from the hole. The finding perhaps has an important meaning in engineering. More >

Bingfei Liu¹, Guansuo Dui^2,3, Lijun Xue², Benming Xie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.3, pp. 239-260, 2013, DOI:10.32604/cmes.2013.094.239

Abstract Analytical solutions are derived for the macroscopic behaviors of a Shape Memory Alloy (SMA) thick-walled cylinder subjected to internal pressure and radial temperature gradient. The Tresca transformation criterion and linear hardening are used. Equations are given for the radial and circumferential stresses, transformation strains and martensite volume fractions at both the elastic step and the transformation step. Numerical results are presented and in good agreement with the finite element simulations. More >

Y.C. Shiah¹, C. L. Tan², R.F. Lee¹

CMES-Computer Modeling in Engineering & Sciences, Vol.69, No.2, pp. 167-198, 2010, DOI:10.3970/cmes.2010.069.167

Abstract In this paper, fully explicit, algebraic expressions are derived for the first and second derivatives of the Green's function for the displacements in a three dimensional anisotropic, linear elastic body. These quantities are required in the direct formulation of the boundary element method (BEM) for determining the stresses at internal points in the body. To the authors' knowledge, similar quantities have never previously been presented in the literature because of their mathematical complexity. Although the BEM is a boundary solution numerical technique, solutions for the displacements and stresses at internal points are sometimes required for some engineering applications. To this… More >

Cheng-Hung Huang¹, Chi-An Chen¹

CMES-Computer Modeling in Engineering & Sciences, Vol.36, No.1, pp. 1-22, 2008, DOI:10.3970/cmes.2008.036.001

Abstract A three-dimensional shape identification problem (or inverse geometry problem) in estimating the unknown irregular shape of internal cavity by using the steepest descent method (SDM) and a general purpose commercial code CFD-RC is examined in this study based on the simulated measured temperature distributions on the outer surface by infrared thermography. The advantage of calling CFD-RC as a subroutine in the present shape identification problem lies in its characteristics of easily-handling the problem considered here since the auto mesh function of CFD-RC enables the handling of this moving boundary problem. \newline Three test cases are performed to test the validity… More >

Chein-Shan Liu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.12, No.3, pp. 161-180, 2006, DOI:10.3970/cmes.2006.012.161

Abstract Materials' internal spacetime may bear certain similarities with the external spacetime of special relativity theory. Previously, it is shown that material hardening and anisotropy may cause the internal spacetime curved. In this paper we announce the third mechanism of mixed-control to cause the curvedness of internal spacetime. To tackle the mixed-control problem for a Prager kinematic hardening material, we demonstrate two new formulations. By using two-integrating factors idea we can derive two Lie type systems in the product space of M^m+1⊗Mⁿ⁺¹. The Lie algebra is a direct sum of so(m,1)⊕so(n,1), and correspondingly the symmetry group is a direct product of… More >

Caibin Zeng¹, Qigui Yang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.59, No.1, pp. 65-78, 2010, DOI:10.3970/cmes.2010.059.065

Abstract In this paper, a fractional order model is established to describe HIV internal viral dynamics involving HAART effect. First, the model is proved to possess non-negative solutions as desired in any population dynamics. Then, a detailed analysis is carried out to study the stability of equilibrium points. Numerical simulations are presented to illustrate the stability analysis. More >

Cheng-Hung Huang¹, Meng-Ting Chaing¹

CMES-Computer Modeling in Engineering & Sciences, Vol.53, No.2, pp. 153-180, 2009, DOI:10.3970/cmes.2009.053.153

Abstract A three-dimensional thermal tomography problem (or inverse geometry problem) in estimating the unknown irregular shape of interfacial enclosure (or surface) for a multiple region domain with an internal cavity by using the steepest descent method (SDM) and a general purpose commercial code CFD-ACE+ is examined in the present work based on the simulated measured temperature distributions on the outer surface obtained by infrared thermography. The advantage of calling CFD-ACE+ as a subroutine in this thermal tomography problem lies in its characteristics of easily-handling the moving boundary problem considered here since it has the function of automatic grid generation. Three test… More >

Q. Ma¹, C. Levy², M. Perl³

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.2, pp. 95-110, 2008, DOI:10.3970/cmes.2008.029.095

Abstract Networks of radial and longitudinally-coplanar, internal, surface cracks are typical in rifled, autofrettaged, gun barrels. In two previous papers, the separate effects of large arrays of either radial or longitudinally-coplanar semi-elliptical, internal, surface cracks in a thick-walled, cylindrical, pressure vessel under both ideal and realistic autofrettage were studied. When pressure is considered solely, radial crack density and longitudinal crack spacing were found to have opposing effects on the prevailing stress intensity factor, K_IP. Furthermore, the addition of the negative stress intensity factor (SIF), K_IA, resulting from the residual stress field due to autofrettage, whether ideal or realistic, tended to decrease… More >