Alireza Sarebanha^1,*, Andreas H. Schellenberg², Matthew J. Schoettler³, Gilberto Mosqueda⁴, Stephen A. Mahin^†

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.3, pp. 693-717, 2019, DOI:10.32604/cmes.2019.04846

Abstract Hybrid simulation can be a cost effective approach for dynamic testing of structural components at full scale while capturing the system level response through interactions with a numerical model. The dynamic response of a seismically isolated structure depends on the combined characteristics of the ground motion, bearings, and superstructure. Therefore, dynamic full-scale system level tests of isolated structures under realistic dynamic loading conditions are desirable towards a holistic validation of this earthquake protection strategy. Moreover, bearing properties and their ultimate behavior have been shown to be highly dependent on rate-of-loading and scale size effects, especially under extreme loading conditions. Few… More >

Changwei Huang^1,*, Philip A. Williams²

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 261-272, 2019, DOI:10.32604/cmes.2019.06681

Abstract This paper examines the evolution of the interfacial deflection energy release rates in multilayered structures under four-point bending. The J-integral and the extended finite element method (XFEM) are adopted to investigate the evolution of the interfacial deflection energy release rates of composite structures. Numerical results not only verify the accuracy of analytical solutions for the steady-state interfacial deflection energy release rate, but also provide the evolutionary history of the interfacial deflection energy release rate under different crack lengths. In addition, non-dimensional parametric analyses are performed to discuss the effects of normalized ratios of the crack length, the elastic modulus, and… More >

John D. Clayton^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 333-350, 2019, DOI:10.32604/cmes.2019.06342

Abstract A theory invoking concepts from differential geometry of generalized Finsler space in conjunction with diffuse interface modeling is described and implemented in finite element (FE) simulations of dual-phase polycrystalline ceramic microstructures. Order parameters accounting for fracture and other structural transformations, notably partial dislocation slip, twinning, or phase changes, are dimensionless entries of an internal state vector of generalized pseudo-Finsler space. Ceramics investigated in computations are a boron carbide-titanium diboride (B₄C-TiB₂) composite and a diamond-silicon carbide (C-SiC) composite. Deformation mechanisms-in addition to elasticity and cleavage fracture in grains of any phase-include restricted dislocation glide (TiB₂ phase), deformation twinning (B₄C and β-SiC… More >

Yana Wang^1,2,3,4, Ruodi Jia^1,5, Fengrui Liu^1,5,6,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.1, pp. 215-234, 2019, DOI:10.32604/cmes.2019.06542

Abstract Delamination and matrix cracking are two common failure mechanisms in composite structures, and are usually coupled with each other, leading to multiple failures pattern. This paper proposed a fast damage prediction methodology for composite laminated structures based on the ply-by-ply 2D (two dimensional) FE model of composite laminates in the transverse plane. The layer-wise 2D FE model was firstly used in conjunction with the integrated XFEM/CE strategy, which simulated the interface delamination with cohesive elements and the intra-ply matrix crack with XFEM (extended finite element method). To realize ply-by-ply 2D FE (finite element) modeling of composite laminates, two 2D material… 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 >

Zhijie Huang^1,2,3, Zuyu Chen^1,2,3, Xiaodan Ren^4,*, Jing Hu³, Xuedong Zhang³, Lu Hai⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 139-155, 2019, DOI:10.31614/cmes.2019.04596

Abstract Damage and threats to hydraulic and submarine structures by underwater explosions (UNDEXs) have raised much attention. The centrifuge model test, compared to prototype test, is a more promising way to examine the problem while reducing cost and satisfying the similitude requirements of both Mach and Froude numbers simultaneously. This study used a systematic approach employing centrifuge model tests and numerical simulations to investigate the effects of UNDEXs on an air-backed steel plate. Nineteen methodical centrifuge tests of UNDEXs were conducted. The shock wave pressure, bubble oscillation pressure, acceleration and the strain of the air-backed steel plate were recorded and compared… More >

Gaoyang Li¹, Xiaorui Song², Aike Qiao³, Makoto Ohta^4,5,*

CMES-Computer Modeling in Engineering & Sciences, Vol.117, No.2, pp. 143-155, 2018, DOI:10.31614/cmes.2018.04100

Abstract For patients with type 2 diabetes, the evaluation of pulse waveform characteristics is helpful to understand changes in arterial stiffness. However, there is a lack of comprehensive analysis of pulse waveform parameters. Here, we aimed to investigate the changes in pulse waveform characteristics in patients with type 2 diabetes due to increased arterial stiffness. In this study, 25 patients with type 2 diabetes and 50 healthy subjects were selected based on their clinical history. Age, height, weight, blood pressure, and pulse pressure were collected as the subjects’ basic characteristics. The brachial-ankle pulse wave velocity (baPWV) was collected as an index… More >

Mena E. Tawfik^{1, 2}, Peter L. Bishay^{3, *}, Edward A. Sadek¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.1, pp. 105-129, 2018, DOI:10.3970/cmes.2018.115.105

Abstract Monte Carlo Simulations (MCS), commonly used for reliability analysis, require a large amount of data points to obtain acceptable accuracy, even if the Subset Simulation with Importance Sampling (SS/IS) methods are used. The Second Order Reliability Method (SORM) has proved to be an excellent rapid tool in the stochastic analysis of laminated composite structures, when compared to the slower MCS techniques. However, SORM requires differentiating the performance function with respect to each of the random variables involved in the simulation. The most suitable approach to do this is to use a symbolic solver, which renders the simulations very slow, although… More >

Junmeng Li¹, Yanli Huang¹, Wenyue Qi¹, Guoqiang Kong¹, Tianqi Song¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.1, pp. 85-103, 2018, DOI:10.3970/cmes.2018.115.085

Abstract In fully mechanized solid backfilling mining (FMSBM), the loose gangues backfill body (LGBB) that filled into the goaf becomes the main body of bearing the overburden load. The deformation resistance of LGBB is critical for controlling overburden movement and surface subsidence. During the process of load bearing, LGBB will experience grain crushing, which has a significant effect on its deformation resistance. Gangues block will be accompanied with obvious acoustic emissions (AE) features in process of slipping, flipping and damaging. Under confined compression test, monitoring the AE parameters of LGBB can reveal the impact mechanism of grain crushing on LGBB deformation.… 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 the RCA algorithm are presented.… More >