Tengjin Zhao¹, Jing Zhang¹, Zhilin Li², Zhiyue Zhang^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.1, pp. 83-104, 2019, DOI:10.32604/cmes.2019.04483

Abstract The validity of the tangent linear model (TLM) is studied numerically using the example of the Lorenz equations in this paper. The relationship between the limit of the validity time of the TLM and initial perturbations for the Lorenz equations is investigated using the Monte Carlo sampling method. A new error function between the nonlinear and the linear evolution of the perturbations is proposed. Furthermore, numerical sensitivity analysis is carried to establish the relationship between parameters and the validity of the TLM, such as the initial perturbation, the prediction time, the time step size and so on, by the method… More >

Jin Yang¹, Tao Li¹, Gang Liang^1,*, Wenbo He², Yue Zhao³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.1, pp. 1-23, 2019, DOI:10.32604/cmes.2019.04727

Abstract Deep Learning presents a critical capability to be geared into environments being constantly changed and ongoing learning dynamic, which is especially relevant in Network Intrusion Detection. In this paper, as enlightened by the theory of Deep Learning Neural Networks, Hierarchy Distributed-Agents Model for Network Risk Evaluation, a newly developed model, is proposed. The architecture taken on by the distributed-agents model are given, as well as the approach of analyzing network intrusion detection using Deep Learning, the mechanism of sharing hyper-parameters to improve the efficiency of learning is presented, and the hierarchical evaluative framework for Network Risk Evaluation of the proposed… More >

M. Nagaraj^1,*, A. John Presin Kumar², C. Ezilarasan³, Rishab Betala⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 679-692, 2019, DOI:10.31614/cmes.2019.04924

Abstract The paper proposes a simulated 3D Finite Element Model (FEM) for drilling of Nickel based super alloy known as Nimonic C-263. The Lagrangian finite element model-based simulations were performed to determine the thrust force, temperature generation, effective stress, and effective strain. The simulations were performed according to the L27 orthogonal array. A perfect plastic work piece was assumed, and the shape is considered to be cylindrical. The spindle speed, feed rate, and point angle were considered as the input parameters. The work piece was modeled by Johnson–Cook (JC) material model and tungsten carbide (WC) was chosen as the drill bit… More >

Liwei Wu¹, Dan Huang^1,*, Yepeng Xu¹, Lei Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 561-581, 2019, DOI:10.31614/cmes.2019.04347

Abstract Strain hardening and strain rate play an important role in dynamic deformation and failure problems such as high-velocity impact cases. In this paper, a non-ordinary state-based peridynamic model for failure and damage of concrete materials subjected to impacting condition is proposed, taking the advantages of both damage model and non-local peridynamic method. The Holmquist-Johnson-Cook (HJC) model describing the mechanical character and damage of concrete materials under large strain, high strain rate and high hydrostatic pressure was reformulated in the framework of non-ordinary state-based peridynamic theory, and the corresponding numerical approach was developed. The proposed model and numerical approach were validated… More >

Zhanqi Cheng¹, Zhenyu Wang¹, Zhongtao Luo^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 509-527, 2019, DOI:10.31614/cmes.2019.04339

Abstract In this work, a bond-based peridynamics (PD) model was built to analyze the dynamic fracture of shale material. Both the the convergence studies and the result of dynamic crack propagation were presented. As well-known, crack propagation, aggregation, and bifurcation play an critical role in the failure analysis of brittle materials such as shale. The dynamic crack propagation and branching analysis of shale by using the PD method were discussed. Firstly, the valid and accuracy of the PD model for the rock materials was verified by comparing with the existed numerical results. Secondly, we discussed the convergence both with uniform grid… More >

Masaki Izawa¹, Ryota Araki¹, Tatsuro Suzuki¹, Kaito Watanabe², Kazuhito Misaji^3,*

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.3, pp. 493-507, 2019, DOI:10.31614/cmes.2019.04470

Abstract Primary purpose of this research is to create a three-dimensional musculoskeletal mathematical model of a driver of a car using a motion capture system. The model is then used in an analysis of drive torque around joints and attached muscles as a vehicle travels in different travel modes and damping force settings to examine ‘burdens’ for the driver. Previous studies proposed a method of quantifying the degree of musculoskeletal load in simple human motion from the changes in drive torque around joints and attached muscles. However, examination of the level of burdens for the driver while driving using this method… More >

Zhaoli Tian^1,2, Yunlong Liu^1,2,*, Shiping Wang¹, A Man Zhang¹, Youwei Kang³

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 397-423, 2019, DOI:10.31614/cmes.2019.04419

Abstract The low frequency load of an underwater explosion bubble and the generated waves can cause significant rigid motion of a ship that threaten its stability. In order to study the fluid-structure interaction qualitatively, a two-dimensional underwater explosion bubble dynamics model, based on the potential flow theory, is established with a double-vortex model for the doubly connected bubble dynamics simulation, and the bubble shows similar dynamics to that in 3-dimensional domain. A fully nonlinear fluid-structure interaction model is established considering the rigid motion of the floating body using the mode-decomposition method. Convergence test of the model is implemented by simulating the… More >

Jie Wang¹, Wei Jiang^1,*, Qi Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 377-395, 2019, DOI:10.31614/cmes.2019.01836

Abstract A elastic-plastic fatigue crack growth (FCG) finite element model was developed for predicting crack growth rate under cyclic load. The propagation criterion for this model was established based on plastically dissipated energy. The crack growth simulation under cyclic computation was implemented through the ABAQUS scripting interface. The predictions of this model are in good agreement with the results of crack propagation experiment of compact tension specimen made of 304 stainless steel. Based on the proposed model, the single peak overload retardation effect of elastic-plastic fatigue crack was analyzed. The results shows that the single peak overload will reduce the accumulation… More >

Davood Afshari^1,*, Soheil Mirzaahamdi¹, Zuheir Barsoum²

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 275-290, 2019, DOI:10.31614/cmes.2019.03880

Abstract The use of magnesium alloys has been rapidly increased due to their ability to maintain high strengths at light weights. However weldability of steels and aluminum alloys by using resistance spot weld (RSW) process is a major issue, because it cannot be directly utilized for magnesium alloys. In this study, a structural-thermal-electrical finite element (FE) model has been developed to predict the distribution of residual stresses in RSW AZ61 magnesium alloy. Thermophysical and thermomechanical properties of AZ61 magnesium alloy have been experimentally determined, and have been used in FE model to increase the accuracy of the model. X-ray diffraction (XRD)… More >

Tianliang Qin¹, Libin Zhao^2,3,*, Jifeng Xu¹, Fengrui Liu^2,3,4, Jianyu Zhang⁵

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 157-176, 2019, DOI:10.31614/cmes.2019.04379

Abstract Progressive damage models (PDMs) have been increasingly used to simulate the failure process of composite material structures. To accurately simulate the damage in each ply, 3D PDMs of composite materials have received more attention recently. A characteristic element length (CEL), which is an important dimensional parameter of PDMs for composite materials, is quite difficult to obtain for 3D elements, especially considering the crack directions during damage propagation. In this paper, CEL models for 3D elements in PDMs of unidirectional composite structures are presented, and their approximate formulae are deduced. The damage in unidirectional composite materials can be divided into fiber… More >