Open Access
ARTICLE
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 >
Open Access
ARTICLE
Xue-cong Liu1, Qing Zhang1,2, Xiao-zhou Xia1
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 411-427, 2017, DOI:10.3970/cmes.2017.113.411
Abstract The manuscript titled “The Stable Explicit Time Stepping Analysis with a New Enrichment Scheme by XFEM,” has been retracted from the Computer Modeling in Engineering & Sciences (CMES), vol. 113, no. 4. Retraction of this article is made upon the request of the authors, Xue-cong Liu, Qing Zhang, and Xiao-zhou Xia. The authors submitted their manuscript on October 7, 2017, and the authors later made a separate request to withdraw their submission when it was still being reviewed. Due to the glitches of the old submission system and failed communications between the managing editor and the corresponding author, the withdraw… More >
Open Access
ARTICLE
Yi Xue1,2,3
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 429-441, 2017, DOI:10.3970/cmes.2017.113.429
Abstract The lack of research on the effect of diffusion on methane extraction leads to low methane concentration and low utilization. The Comsol Multiphysics software is used to solve the numerical gas and solid coupled model which considers the diffusion of coal matrix, fracture seepage, permeability evolution and coal deformation. The simulation results reveal the effect of diffusion process on methane migration. The gas diffusion rate is relatively high in the initial stage. With the increase in time, the difference between coal fractures and coal matrix blocks becomes lower and the gas diffusion rate decreases gradually. The gas seepage rate decreases… More >
Open Access
ARTICLE
Sunil Kr. Jha1, Zulfiqar Ahmad2
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 443-459, 2017, DOI:10.3970/cmes.2017.113.443
Abstract Microbial population and enzyme activities are the significant indicators of soil strength. Soil microbial dynamics characterize microbial population and enzyme activities. The present study explores the development of efficient predictive modeling systems for the estimation of specific soil microbial dynamics, like rock phosphate solubilization, bacterial population, and ACC-deaminase activity. More specifically, optimized subtractive clustering (SC) and Wang and Mendel's (WM) fuzzy inference systems (FIS) have been implemented with the objective to achieve the best estimation accuracy of microbial dynamics. Experimental measurements were performed using controlled pot experiment using minimal salt media with rock phosphate as sole carbon source inoculated with… More >
Open Access
ARTICLE
V. Thiyagarajan1, P. Somasundaram2
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 461-473, 2017, DOI:10.3970/cmes.2017.113.461
Abstract This paper proposes a novel single phase symmetrical and asymmetrical type extendable multilevel inverter topology with minimum number of switches. The basic circuit of the proposed inverter topology consist of four dc voltage sources and 10 main switches which synthesize 9-level output voltage during symmetrical operation and 17-level output voltage during asymmetrical operation. The comparison between the proposed topology with conventional and other existing inverter topologies is presented in this paper. The advantages of the proposed inverter topology includes minimum switches, less harmonic distortion and minimum switching losses. The performance of the proposed multilevel inverter topology has been analyzed in… More >
Open Access
ARTICLE
Meng Li1, Kanhua Su1, Zijian Li2, Dongjie Li3, Lifu Wan1
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 475-495, 2017, DOI:10.3970/cmes.2017.113.475
Abstract With the consideration of the randomness of complex geologic parameters for ultra-deep wells, an uncertainty analysis method is presented for the extrusion load on casing in ultra-deep wells through complex formation at a certain confidence level. Based on the extrusion load model for casing in ultra-deep wells and the prerequisite of integrity of formation-cement ring-casing, the probability and statistics theory is introduced and the sensitivity analysis on the uncertainty of extrusion load on casing is conducted. The distribution types of each formation parameters are determined statistically. The distribution type and distribution function of the extrusion load on casing are derived.… More >
Open Access
ARTICLE
Y. Sadeghi Ferezghi1, M.R. Sohrabi1, S.M Mosavi Nezhad 2, *
CMES-Computer Modeling in Engineering & Sciences, Vol.113, No.4, pp. 497-520, 2017, DOI:10.3970/cmes.2017.113.497
Abstract In this paper, dynamic behavior of non-symmetric Functionally Graded (FG) cylindrical structure under shock loading is carried out. Dynamic equations in the polar coordinates are drawn out using Meshless Local Petrov-Galerkin (MLPG) method. Nonlinear volume fractions are used for radial direction to simulate the mechanical properties of Functionally Graded Material (FGM). To solve dynamic equations of non-symmetric FG cylindrical structure in the time domain, the MLPG method are combined with the Laplace transform method. For computing the inverse Laplace transform in the present paper, the Talbot algorithm for the numerical inversion is used. To verify the obtained results by the… More >