Zhengzheng Cao¹, Ping Xu^1,*, Zhenhua Li², Minxia Zhang¹, Yu Zhao¹, Wenlong Shen²

CMC-Computers, Materials & Continua, Vol.54, No.2, pp. 137-159, 2018, DOI:10.3970/cmc.2018.054.137

Abstract In the traditional mining technology, the coal resources trapped beneath surface buildings, railways, and water bodies cannot be mined massively, thereby causing the lower coal recovery and dynamic disasters. In order to solve the aforementioned problems, the roadway backfilling mining technology is developed and the joint bearing mechanism of coal pillar and backfilling body is presented in this paper. The mechanical model of bearing system of coal pillar and backfilling body is established, by analyzing the basic characteristics of overlying strata deformation in roadway backfilling mining technology. According to the Ritz method in energy variation principle, the elastic solution expression… More >

Arzu Turan Dincel¹, Surkay D. Akbarov^2,3

CMC-Computers, Materials & Continua, Vol.53, No.3, pp. 249-270, 2017, DOI:10.32604/cmc.2017.053.265

Abstract This paper deals with the mathematical modelling and 3D FEM study of the energy release rate (ERR) in the band crack’s front contained in the orthotropic thick rectangular plate which is stretched or compressed initially before the loading of the crack's edge planes. The initial stretching or compressing of the plate causes uniformly distributed normal stress to appear acting in the direction which is parallel to the plane on which the band crack is located. After the appearance of the initial stress in the plate it is assumed that the crack's edge planes are loaded with additional uniformly distributed normal… More >

ZichunYang¹, Gaohui Su^1,2, Bin Chen¹

CMC-Computers, Materials & Continua, Vol.51, No.1, pp. 43-62, 2016, DOI:10.3970/cmc.2016.051.043

Abstract The molecular dynamics (MD) simulations were used to understand the heat transfer process between the gas phase and the solid skeleton in the nanoporous silica aerogels. The amorphous silica nanoparticles were generated by the MD simulations and the energy accommodation coefficient (EAC) between the gases and the nanoparticles was calculated based on the results of the nonequilibrium molecular dynamics (NEMD) simulations. The apparent thermal conductivity (ATC) of the gases between the heat source and heat sink was also obtained. The effects of the temperature, the particle diameter and the molecule type on the EAC and the ATC were investigated. The… More >

W.Xu¹, A.M. Waas²

CMC-Computers, Materials & Continua, Vol.46, No.3, pp. 165-194, 2015, DOI:10.3970/cmc.2015.046.165

Abstract Plastic deformation and splitting are two important mechanisms of energy dissipation when metal tubes undergo axial crushing. Isotropic J2 plasticity theory combined with a failure criterion is used to model axial splitting and curling of metal tubes undergoing axial crush. The proposed material model is implemented within a finite element (FE) framework using the user material subroutine VUMAT option available in the commercial code ABAQUS. Experimental results from literature are used to validate the model. The predicted splitting and curling patterns as well as the load-displacement response agree well with the experimental observations. The present material model is also used… More >

Vishal Shreyans Shah¹, Henyl Rakesh Shah², Pijush Samui³, A. Ramachra Murthy⁴

CMC-Computers, Materials & Continua, Vol.44, No.2, pp. 73-84, 2014, DOI:10.3970/cmc.2014.044.073

Abstract This paper deals with the development of models for prediction of facture parameters, namely, fracture energy and ultimate load of high strength and ultra high strength concrete based on Minimax Probability Machine Regression (MPMR) and Extreme Learning Machine (ELM). MPMR is developed based on Minimax Probability Machine Classification (MPMC). ELM is the modified version of Single Hidden Layer Feed Foreword Network (SLFN). MPMR and ELM has been used as regression techniques. Mathematical models have been developed in the form of relation between several input variables such as beam dimensions, water cement ratio, compressive strength, split tensile strength, notch depth, and… More >

Yuvaraj P¹, A Ramachra Murthy², Nagesh R Iyer³, S.K. Sekar⁴, Pijush Samui⁵

CMC-Computers, Materials & Continua, Vol.41, No.3, pp. 193-214, 2014, DOI:10.3970/cmc.2014.041.193

Abstract This paper presents fracture mechanics based Artificial Neural Network (ANN) model to predict the fracture characteristics of high strength and ultra high strength concrete beams. Fracture characteristics include fracture energy (Gf), critical stress intensity factor (KIC) and critical crack tip opening displacement (CTODc). Failure load of the beam (Pmax) is also predicated by using ANN model. Characterization of mix and testing of beams of high strength and ultra strength concrete have been described. Methodologies for evaluation of fracture energy, critical stress intensity factor and critical crack tip opening displacement have been outlined. Back-propagation training technique has been employed for updating… More >

Xue-Qian Fang^1,2, Hong-Wei Liu¹, Yong-Mao Zhao¹, Guo-Quan Nie^1,1 and Jin-Xi Liu¹

CMC-Computers, Materials & Continua, Vol.40, No.2, pp. 145-164, 2014, DOI:10.3970/cmc.2014.040.145

Abstract Electro-elastic surface/interface around nano-sized piezoelectric inclusions shows great effect on the response of piezoelectric nano-structures. In this paper, a theoretical model is proposed to examine the surface/interface effect on the electromechanical responses around a nano-sized elliptical piezoelectric inclusion embedded in an infinite piezoelectric matrix under far-field loading with an arbitrary angle, and the effect of loading angle is considered Combining the conformal mapping technique and electro-elastic surface/interface theory, a closed form solution of this problem is obtained and the interactive effect between the surface/interface and the aspect ratio of the elliptical inclusion is examined. More >

E. J. Pineda¹, B. A. Bednarcyk¹, A. M. Waas², S. M. Arnold¹

CMC-Computers, Materials & Continua, Vol.35, No.2, pp. 119-154, 2013, DOI:10.3970/cmc.2013.035.119

Abstract A mesh objective crack band model was implemented within the generalized method of cells micromechanics theory. This model was linked to a macroscale finite element model to predict post-peak strain softening in composite materials. Although a mesh objective theory was implemented at the microscale, it does not preclude pathological mesh dependence at the macroscale. To ensure mesh objectivity at both scales, the energy density and the energy release rate must be preserved identically across the two scales. This requires a consistent characteristic length or localization limiter. The effects of scaling (or not scaling) the dimensions of the microscale repeating unit… More >

Xue-Qian Fang^1,2, Ming-Juan Huang¹, Jun-Ying Wu³, Guo-Quan Nie¹, Jin-Xi Liu¹

CMC-Computers, Materials & Continua, Vol.33, No.2, pp. 199-211, 2013, DOI:10.3970/cmc.2013.033.199

Abstract In nanocomposites, coated nano-fibers are often used to obtain good performance, and the high interface-to-volume ratio shows great effect on the macroscopic effective properties of nanocomposites. In this study, the effect of interface energy around the unidirectional coated nanofibers on the effective dynamic effective properties is explicitly addressed by effective medium method and wave function expansion method. The multiple scattering resulting from the series coating nano-fibers is reduced to the problem of one typical nano-fiber in the effective medium. The dynamic effective shear modulus is obtained on the basis of the derived imperfect interface conditions. Analyses show that the effect… More >

Surkay D. Akbarov^1,2, Arzu Turan³

CMC-Computers, Materials & Continua, Vol.24, No.3, pp. 257-270, 2011, DOI:10.3970/cmc.2011.024.257

Abstract The influence of the initial finite stretching or compressing of the strip containing a single crack on the Energy Release Rate (ERR) and on the SIF of mode I at the crack tips is studied by the use of the Three-Dimensional Linearized Theory of Elasticity. It is assumed that the edges of the crack are parallel to the face planes of the strip and the ends of the strip are simply supported. The initial finite strain state arises by the uniformly distributed normal forces acting at the ends of the strip. The additional normal forces act on the edges of… More >