Xiangyan Tang¹, Qidong Zheng^1,*, Jieren Cheng^1,2, Victor S. Sheng³, Rui Cao¹, Meizhu Chen¹

CMC-Computers, Materials & Continua, Vol.60, No.3, pp. 1263-1281, 2019, DOI:10.32604/cmc.2019.06173

Abstract The existing network security situation assessment methods cannot effectively assess the Distributed denial-of-service (DDoS) attack situation. In order to solve these problems, we propose a DDoS attack situation assessment method via optimized cloud model based on influence function. Firstly, according to the state change characteristics of the IP addresses which are accessed by new and old user respectively, this paper defines a fusion feature value. Then, based on this value, we establish a V-Support Vector Machines (V-SVM) classification model to analyze network flow for identifying DDoS attacks. Secondly, according to the change of new and old IP addresses, we propose… More >

M. Ozisik^1,*, M. A. Mehdiyev², S. D. Akbarov^2,3

CMC-Computers, Materials & Continua, Vol.54, No.2, pp. 103-136, 2018, DOI:10.3970/cmc.2018.054.103

Abstract The dynamics of the moving-with-constant-velocity internal pressure acting on the inner surface of the hollow circular cylinder surrounded by an infinite elastic medium is studied within the scope of the piecewise homogeneous body model by employing the exact field equations of the linear theory of elastodynamics. It is assumed that the internal pressure is point-located with respect to the cylinder axis and is axisymmetric in the circumferential direction. Moreover, it is assumed that shear-spring type imperfect contact conditions on the interface between the cylinder and surrounding elastic medium are satisfied. The focus is on the influence of the mentioned imperfectness… More >

Yi Xue^1,2,3, Faning Dang², Rongjian Li², Liuming Fan², Qin Hao⁴, Lin Mu², Yuanyuan Xia²

CMC-Computers, Materials & Continua, Vol.54, No.1, pp. 43-59, 2018, DOI:10.3970/cmc.2018.054.043

Abstract In the seepage-stress-damage coupled process, the mechanical properties and seepage characteristics of coal are distinctly different between pre-peak stage and post-peak stage. This difference is mainly caused by damage of coal. Therefore, in the process of seepage and stress analysis of coal under the influence of excavation or mining, we need to consider the weakening of mechanical properties and the development of fractures of damaged coal. Based on this understanding, this paper analyzes the influence of damage on mechanics and seepage behavior of coal. A coupled model is established to analyze the seepage-stress-damage coupled process of coal. This model implemented… 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 >

L.S. Melro^1,2, L.R. Jensen¹

CMC-Computers, Materials & Continua, Vol.53, No.2, pp. 109-127, 2017, DOI:10.3970/cmc.2017.053.111

Abstract Molecular dynamics simulations were applied in order to calculate the Young’s modulus of graphene functionalized with carboxyl, hydroxyl, carbonyl, hydrogen, methyl, and ethyl groups. The influence of the grafting density with percentages of 3, 5, 7, and 10% and the type of distribution as a single cluster or several small clusters were also studied. The results show that the elastic modulus is dependent on the type of functional groups. The increasing coverage density also evidenced a decrease of the Young’s modulus, and the organization of functional groups as single cluster showed a lesser impact than for several small clusters. Furthermore,… More >

Mohamed I. A. Othman^1,2,3, W. M. Hasona^2,4, Nehal T. Mansour^2,5

CMC-Computers, Materials & Continua, Vol.45, No.3, pp. 203-220, 2015, DOI:10.3970/cmc.2015.045.203

Abstract The problem of the generalized thermoelastic medium for three different theories under the effect of a gravitational field is investigated. The Lord- Shulman, Green-Naghdi III, three-phase-lag theories are discussed with twotemperature. The normal mode analysis is used to obtain the analytical expressions of the displacement components, force stress, thermodynamic temperature and conductive temperature. The numerical results are given and presented graphically, when the thermal force is applied. Comparisons are made with the results predicted by three-phase-lag model, Green-Naghdi III and Lord-Shulman theories in the presence and absence of gravity as well as two temperature. More >

Ridha Djebali¹, Mohsen Toujani², Bernard Pateyron³

CMC-Computers, Materials & Continua, Vol.37, No.3, pp. 147-160, 2013, DOI:10.3970/cmc.2013.037.147

Abstract In this paper a study of the atmospheric plasma spraying process was conducted. The Jets&Poudres code was used to solve the partial differential equations for the conservation of mass, momentum and energy involved in the problem together with the K-e turbulent model. The Taguchi technique was used to study the influence of processing factors on droplet impact properties obtained on dense zirconia (ZrO₂) under H₂Ar75% plasma gas that allow optimal functioning condition. The test of the operating parameters for the studied ranges showed that the "thermal power" factor plays a key role on the state of sprayed powder. It was… More >

K. C. Liu¹, S. M. Arnold²

CMC-Computers, Materials & Continua, Vol.35, No.1, pp. 35-65, 2013, DOI:10.3970/cmc.2013.035.035

Abstract It is well known that failure of a material is a locally driven event. In the case of ceramic matrix composites (CMCs), significant variations in the microstructure of the composite exist and their significance on both deformation and life response need to be assessed. Examples of these variations include changes in the fiber tow shape, tow shifting/nesting and voids within and between tows. In the present work, the influence of many of these scale specific architectural features of woven ceramic composite are examined stochastically at both the macroscale (woven repeating unit cell (RUC)) and structural scale (idealized using multiple RUCs).… More >

Jia-Liang Le¹, Bing Xue¹

CMC-Computers, Materials & Continua, Vol.34, No.3, pp. 251-264, 2013, DOI:10.3970/cmc.2013.034.251

Abstract It has been recently shown that the nominal structural strength of metal-composite structures depends on the structure size, and such dependence is strongly influenced by the stress singularities. Nevertheless, previous studies only focused on structures that exhibit very strong stress singularities, which are close to the crack-like stress singularity. In the actual engineering designs, due to the mismatch of material properties and complex structural geometries, many metalcomposite structures may contain stress singularities that are much weaker than the crack-like stress singularity. This paper presents a numerical study on the size dependence of scaling of fracture of metal-composite hybrid structures for… More >

X. H. Du¹, X. P. Shen¹

CMC-Computers, Materials & Continua, Vol.20, No.3, pp. 225-242, 2010, DOI:10.3970/cmc.2010.020.225

Abstract Aim of this paper is to estimate the integrity of liquefied natural gas (LNG) prestressed storage tank under seismic influence. The coupled Eulerian-Lagrangian (CEL) analysis technique is used to simulate the fluid-structure interaction between LNG and the cylinder of LNG prestressed storage tank. The 3-D model of LNG has been dispersed by Eulerian mesh that is different from traditional analysis method which is called the added mass method. Meanwhile, both of the 3-D models of prestressed rebar and concrete structure are dispersed by Lagrangian mesh. Following conclusions are obtained: 1) Natural frequency of the whole model has been obtained by… More >