Dan Ma^{1, 2}, Hongyu Duan², Qi Zhang^{3, *}, Jixiong Zhang¹, Wenxuan Li², Zilong Zhou², Weitao Liu⁴

CMC-Computers, Materials & Continua, Vol.65, No.3, pp. 2123-2141, 2020, DOI:10.32604/cmc.2020.011430

Abstract Gas fracturing, which overcomes the limitation of hydraulic fracturing, is a potential alternative technology for the development of unconventional gas and oil resources. However, the mechanical principle of gas fracturing has not been learned comprehensively when the fluid is injected into the borehole. In this paper, a damagebased model of coupled thermal-flowing-mechanical effects was adopted to illustrate the mechanical principle of gas fracturing. Numerical simulation tools Comsol Multiphysics and Matlab were integrated to simulate the coupled process during the gas fracturing. Besides, the damage evolution of drilling areas under several conditions was fully analyzed. Simulation results indicate that the maximum… More >

Xiaodan Ren^1,*, Tiancan Huang²

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 411-413, 2020, DOI:10.32604/cmes.2020.012603

Abstract This article has no abstract. More >

Yatin Suri¹, Sheikh Zahidul Islam^{1, *}, Mamdud Hossain¹

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.2, pp. 297-337, 2020, DOI:10.32604/fdmp.2020.08421

Abstract The distribution of proppant injected in hydraulic fractures significantly affects the fracture conductivity and well performance. The proppant transport in thin fracturing fluid used during hydraulic fracturing in the unconventional reservoirs is considerably different from fracturing fluids in the conventional reservoir due to the very low viscosity and quick deposition of the proppants. This paper presents the development of a threedimensional Computational Fluid Dynamics (CFD) modelling technique for the prediction of proppant-fluid multiphase flow in hydraulic fractures. The proposed model also simulates the fluid leak-off behaviour from the fracture wall. The Euler-Granular and CFD-Discrete Element Method (CFD-DEM) multiphase modelling approach… More >

Meijuan Shan^{1, 2}, Libin Zhao^{2, *}, Wei Huang³, Fengrui Liu², Jianyu Zhang^{4, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 101-127, 2020, DOI:10.32604/cmes.2020.09099

Abstract The high demands for load-carrying capability and structural efficiency of composite-metal bolted joints trigger in-depth investigations on failure mechanisms of the joints in hygrothermal environments. However, few studies have been presented to exhaustively reveal hygrothermal effects on the failure of CFRP-metal bolted joints, which differ from CFRP-CFRP or metal-metal bolted joints because of the remarkably different material properties of CFRPs and metals. In this paper, hygrothermal effects on tensile failures of single-lap and double-lap CFRP-aluminum bolted joints were experimentally and numerically investigated. A novel numerical model, in which a hygrothermal-included progressive damage model of composites was established and elastic-plastic models… More >

D. O. Redchyts¹, E. A. Shkvar^{2, *}, S. V. Moiseienko³

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.1, pp. 91-103, 2020, DOI:10.32604/fdmp.2020.07933

Abstract A method to evaluate the properties of turbulent flow in proximity to the vehicle and close to the ground surface has been elaborated. Numerical simulations have been performed on the basis of the Unsteady Reynolds-averaged Navier-Stokes equations (URANS) written with respect to an arbitrary curvilinear coordinate system. These equations have been solved using the Spalart-Allmaras differential one-parametric turbulence model. The method of artificial compressibility has been used to improve the coupling of pressure and velocity in the framework of a finite volume approach. Time-averaged distributions of pressure fields, velocity components, streamlines in the entire area and near the tractor-trailer, as… More >

Shuo Yang¹, Yuanhai Li^{1, 2, ∗}, Xiaojie Tang^{1, 2}, Jinshan Liu^{1, 2}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.2, pp. 633-659, 2020, DOI:10.32604/cmes.2020.07919

Abstract The deformation and damage evolution of sandstone after heat treatment greatly influence the efficient and safe development of deep geothermal energy extraction. To investigate this issue, laboratory confined compression tests and numerical simulations were conducted on pre-holed sandstone specimens after heat treatment. The laboratory test results show that the failure modes are closely related to the heat treatment temperature, with increasing treatment temperature, the failure modes change from mixed and shear modes to a splitting mode. The cracks always initiate from the sidewalls of the hole and then propagate. The failure process inside the hole proceeds as follows: calm period,… More >

Muyi Guo¹, Yan Cai¹, Zhiyong Li^1,2,*

Molecular & Cellular Biomechanics, Vol.16, Suppl.1, pp. 49-49, 2019, DOI:10.32604/mcb.2019.05727

Abstract Observational studies have identified angiogenesis from the adventitial vasa vasorum and intraplaque hemorrhage (IPH) as critical factors in atherosclerotic plaque progression and destabilization. Here we propose a mathematical model incorporating intraplaque neovascularization and hemodynamic calculation for the quantitative evaluation of atherosclerotic plaque hemorrhage. An angiogenic microvasculature based on histology of a patient’s carotid plaque is generated by two-dimensional nine-point model of endothelial cell migration. Three key cells (endothelial cells, smooth muscle cells and macrophages) and three key chemicals (vascular endothelial growth factors, extracellular matrix and matrix metalloproteinase) are involved in the intraplaque angiogenesis model, and described by the reaction-diffusion partial… More >

Vincenzo Gulizzi^1,2, Piervincenzo Rizzo^2,3, Alberto Milazzo⁴

Structural Durability & Health Monitoring, Vol.10, No.1, pp. 19-54, 2014, DOI:10.3970/sdhm.2014.010.019

Abstract The electromechanical impedance (EMI) method is one of the many nondestructive evaluation approaches proposed for the health monitoring of aerospace, civil, and mechanical structures. The method consists of attaching or embedding one or more wafer-type piezoelectric transducers (PZTs) to the system of interest, the host structure, and measuring certain electrical characteristics of the transducers. As these characteristics are also related to the impedance of the host structure, they can be used to infer the mechanical properties of the monitored structure. In the study presented in this paper, we utilize the EMI to monitor the quality of adhesively bonded joints. A… More >

F. Caputo, G. Lamanna, A. Soprano¹

Structural Durability & Health Monitoring, Vol.7, No.4, pp. 283-296, 2011, DOI:10.3970/sdhm.2011.007.283

Abstract The present paper deals with a numerical investigation on hybrid bolted joints between unidirectional, quasi isotropic Carbon Fiber Reinforced Polymer (CFRP) composite and aluminium alloy plates, subjected to traction loads. CFRP composite materials are widely used in aerospace applications, where requirements of weight reduction and structural high performances are very compelling. Composite materials generally present high resistance to fatigue and corrosion but the presence of joints in the structure can cause structural problems and then decrease the structural reliability of jointed component.
A hybrid bolted joint constituted of a metal plate, made of aluminium alloy, and a carbon fiber reinforced… More >

S. Baragetti¹, F. Tordini²

Structural Durability & Health Monitoring, Vol.3, No.3, pp. 165-176, 2007, DOI:10.3970/sdhm.2007.003.165

Abstract The effect of a TiN PVD (Physical Vapor Deposition) coating on the fatigue behaviour of the titanium alloy Ti-6Al-4V was investigated. Fatigue tests were performed on coated and uncoated, both smooth and 120° V-notched, specimens in order to evaluate the influence of the coating on the substrate fatigue resistance. Numerical analyses were carried out in order to determine the stress distributions below the specimen surface and on the coating. Several coating elastic moduli were used in such calculations. The residual stress gradient induced by the coating process deposition and the substrate plasticization were also taken into account with FEM. The… More >