Y.J. Guo¹, J.A. Nairn²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 389-410, 2017, DOI:10.3970/cmes.2017.113.389

Abstract This paper presents the principles and algorithms for simulation of dynamic crack propagation in elastic bodies by the material point method (MPM), from relatively simple two-dimensional cases to full three-dimensional, mixed-mode crack propagation. The paper is intended to give a summary of the latest achievements on simulation of three-dimensional dynamic crack propagation, which is essentially an unexplored area. Application of the methodology presented in this paper to several dynamic crack propagation problems has shown that the MPM is a reliable and powerful approach for simulating three-dimensional, mixed-mode crack propagation. More >

C. F. Loeffle¹, L. Zamprogno², W. J. Mansur³, A. Bulcão⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 367-387, 2017, DOI:10.3970/cmes.2017.113.387

Abstract This study evaluates the effectiveness of a new technique that transforms domain integrals into boundary integrals that is applicable to the boundary element method. Simulations were conducted in which two-dimensional surfaces were approximated by interpolation using radial basis functions with full and compact supports. Examples involving Poisson’s equation are presented using the boundary element method and the proposed technique with compact radial basis functions. The advantages and the disadvantages are examined through simulations. The effects of internal poles, the boundary mesh refinement and the value for the support of the radial basis functions on performance More >

Hong Y. Yeh, Huan J. Keh^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 343-366, 2017, DOI:10.3970/cmes.2017.113.361

Abstract The problem of the steady migration of an axially symmetric prolate particle along its axis of revolution coinciding with the centerline of a circular capillary is investigated semi-analytically in the limit of low Reynolds number, where the viscous fluid may slip at the solid surfaces. A method of distribution of spherical singularities along the axis inside the particle is employed to establish the general solution of the fluid velocity satisfying the boundary conditions at the capillary wall and infinity. The slip condition at the particle surface is then satisfied by using a boundary collocation method… More >

M.T.C. Araújo Fernandes¹, C.O. Cardoso², W.J. Mansur³

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 325-342, 2017, DOI:10.3970/cmes.2017.113.341

Abstract A new adaptive (automatic) time stepping algorithm, called RCA (Rate of Convergence Algorithm) is presented. The new algorithm was applied in nonlinear finite element analysis of path-dependent problems. The step size is adjusted by monitoring the estimated convergence rate of the nonlinear iterative process. The RCA algorithm is relatively simple to implement, robust and its performance is comparable to, and in some cases better than, the automatic load incrementaion algorithm existent in commercial codes. Discussions about the convergence rate of nonlinear iterative processes, an estimation of the rate and a study of the parameters of More >

Ehsan Hedayati¹, Mohammad Vahedi²

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 295-323, 2017, DOI:10.3970/cmes.2017.113.307

Abstract Radius of ceramic cone can largely contribute into final solution of analytic models of penetration into ceramic/metal targets. In the present research, a modified model based on radius of ceramic cone was presented for ceramic/aluminum targets. In order to investigate and evaluate accuracy of the presented analytic model, obtained results were compared against the results of the Florence’s analytic model and also against numerical modeling results. The phenomenon of impact onto ceramic/aluminum composites were modeled using smoothed particle hydrodynamics (SPH) implemented utilizing ABAQUS Software. Results indicated that, with increasing initial velocity and ceramic thickness and… More >

Zhengzheng Cao¹, Feng Du^2,3,4, Zhenhua Li², Qinting Wang¹, Ping Xu¹, Haixiao Lin¹

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 275-293, 2017, DOI:10.3970/cmes.2017.113.287

Abstract The stability of ore pillar in mine is essential for the safe and efficient mining. Based on the energy evolvement rule in ore pillar and roadway roof system, the roadway roof and ore pillar are treated as energy release body and energy dissipation body, respectively. Therefore, the double-block mechanical model is established with energy dissipation body and energy release body, and the energy mechanism of ore pillar instability is obtained, based on the fold catastrophe mathematical theory. The research result indicates that the dynamic instability of ore pillar is a physical instability problem caused by… More >

Ali Bekir YILDIZ¹

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 261-274, 2017, DOI:10.3970/cmes.2017.113.273

Abstract In this paper, a computer-based systematic and efficient formulation method is presented for obtaining the network functions of linear or linearized time-invariant dynamic circuits. The method employs the modified nodal approach to obtain the system equations. The technique is based on developing a matrix formulation for modelling network functions. By using both symbolic manipulation of algebraic expressions and numeric processes, the network functions are expressed with a matrix-based method. Application examples are given to illustrate the features of the method. More >

J.C. Tang¹, C.M. Fu^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.3, pp. 239-259, 2017, DOI:10.3970/cmes.2017.113.249

Abstract In this paper, an efficient interval analysis method called dimension-reduction interval analysis (DRIA) method is proposed to calculate the bounds of response functions with interval variables, which provides a kind of solution method for uncertainty analysis problems of complex structures and systems. First, multi-dimensional function is transformed into multiple one-dimensional functions by extending dimension reduction method to the interval analysis problem. Second, all the one-dimensional functions are transformed to standard quadratic form by second order Taylor expansion method. As a result, the multi-dimensional function is approximately represented by the functions that each interval variable occurs More >

Sanjay Mittal¹, Anubhav Dwivedi¹

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.2, pp. 219-237, 2017, DOI:10.3970/cmes.2017.113.229

Abstract Linear Stability Analysis (LSA) of parallel shear flows, v ia local and global approaches, is presented. The local analysis is carried out by solving the Orr-Sommerfeld (OS) equation using a spectral-collocation method based on Chebyshev polynomials. A stabilized finite element formulation is employed to carry out the global analysis using the linearized disturbance equations in primitive variables. The local and global analysis are compared. As per the Squires theorem, the two-dimensional disturbance has the largest growth rate. Therefore, only two-dimensional disturbances are considered. By its very nature, the local analysis assumes the disturbance field to… More >

Sadık Alper YILDIZEL¹, Muhammet Ensar YİĞİT², Gökhan KAPLAN³

CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.2, pp. 203-218, 2017, DOI:10.3970/cmes.2017.113.211

Abstract Glass fibre reinforced concrete placement technique generates losses due to rebound effects of the already sprayed concrete particles. Rebounded concrete amount cause a significant difference between the initial mix design and emplaced mix compositions. Apart from the structural differences, it comes with a cost increase which was resulted by the splashed concrete amount. Many factors such as viscosity and quantity of mixes dominate this rebound amount in sprayed glass fibre reinforced concrete applications depending on production technologies and processes; however, this research focuses on the spray distance and the angle of the spray gun which More >