Nazia Afrin^a, Yijin Mao^a, Yuwen Zhang^a,*, J. K. Chen^a, Robin Ritter^b, Alan Lampson^b, Jonathan Stohs^c

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-8, 2016, DOI:10.5098/hmt.7.7

Abstract A three-dimensional numerical simulation is conducted for a complex process in a laser-material system, which involves heat and mass transfer in a compressible gaseous phase and chemical reaction during laser irradiation on a urethane paint coated on a stainless steel substrate. A finite volume method (FVM) with a co-located grid mesh that discretizes the entire computational domain is employed to simulate the heating process. The results show that when the top surface of the paint reaches a threshold temperature of 560 K, the polyurethane starts to decompose through chemical reaction. As a result, combustion products CO₂, H₂O and NO₂ are… More >

Tantan Zhu^*, Yao Li

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 457-477, 2021, DOI:10.32604/cmes.2021.014284

Abstract Punch shear tests have been widely used to determine rock shear mechanical properties but without a standard sample geometric dimension suggestion. To investigate the impacts of sample geometric dimensions on shear behaviors in a punch shear test, simulations using Particle Flow Code were carried out. The effects of three geometric dimensions (i.e., disk diameter, ratio of shear surface diameter to disk diameter, and ratio of disk height to shear surface diameter) were discussed. Variations of shear strength, shear stiffness, and shear dilatancy angles were studied, and the fracture processes and patterns of samples were investigated. Then, normal stress on the… More >

Lin Pan, Jinhong Xia, Hongxing Han^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.6, pp. 1219-1228, 2020, DOI:10.32604/fdmp.2020.010545

Abstract In this paper, the discrete element method (DEM) is used to study the microstructure of expansive soils. The results of the numerical calculations are in agreement with the stress-strain triaxial test curve that is obtained for a representative expansive soil. Biaxial compression tests are conducted for different confining pressures (50 kpa, 100 kpa, and 150 kpa). Attention is paid to the following aspects: deviatoric stress, boundary energy, friction energy, bond energy, strain energy, kinetic energy, and the contact force between grains when the test specimen is strained and to the effect of the different confining pressures on the internal crack… More >

Abierdi¹, Yuzhou Xiang², Haiyi Zhong², Xin Gu², Hanlong Liu^{2, 3}, Wengang Zhang^{2, 3, *}

CMC-Computers, Materials & Continua, Vol.63, No.2, pp. 825-844, 2020, DOI:10.32604/cmc.2020.07946

Abstract Tunnel excavation is a complicated loading-unloading-reloading process characterized by decreased radial stresses and increased axial stresses. An approach that considers only loading, is generally used in tunnel model testing. However, this approach is incapable of characterizing the unloading effects induced by excavation on surrounding rocks and hence presents radial and tangential stress paths during the failure process that are different from the actual stress state of tunnels. This paper carried out a comparative analysis using laboratory model testing and particle flow code (PFC^2D)-based numerical simulation, and shed light upon the crack propagation process and, microscopic stress and force chain variations… More >