Papers by Author: Shi Bin Tang

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Authors: Qing Lei Yu, Chun An Tang, Zheng Zhao Liang, Shi Bin Tang
Abstract: This paper presents a new meso-mechanical analysis method of rock failure. The actual inhomogeneity of rock at meso-scale level is represented by processing the image of rock section and incorporated into Realistic Failure Process Analysis code (abbreviated as RFPA2D). Here, this numerical tool is employed to study the fracture phenomena of granite sample considering the interface strength between mineral grains. Numerical results show that interface strength has significant influence on the strength of sample and its failure mode. The larger the interface strength is, the more brittle rock samples become and the strength is bigger. With the interface strength increasing, failure mode gradually varies from intergranular frature to transgranular fracture.
Authors: Tao Xu, Shan Yong Wang, Chun An Tang, Li Song, Shi Bin Tang
Abstract: In this paper, a coupled thermal-mechanical-damage model, Material Failure Process Analysis for Thermo code (abbreviated as MFPA-thermo), was applied to investigate the formation, extension and coalescence of cracks in FRCs, caused by the thermal mismatch of the matrix and the particles under uniform temperature variations. The effects of the thermal mismatch between the matrix and fibers on the stress distribution and crack development were also numerically studied. The influences of the material heterogeneity, the failure patterns of FRCs at varied temperatures are simulated and compared with the experimental results in the present paper. The results show that the mechanisms of thermal damage and fracture of the composite remarkedably depend on the difference between the coefficients of thermal expansion of the fibers and the matrix on a meso-scale. Meanwhile, the simulations indicate that the thermal cracking of the FRCs at uniform varied temperatures is an evolution process from diffused damage, nucleation, and finally linkage of cracks.
Authors: Shi Bin Tang, Chun An Tang, Zheng Zhao Liang, Qing Lei Yu
Abstract: Thermal stresses are identified as one of the major causes of concrete failure. In order to consider the heterogeneity of concrete at mesoscopic level, and to simulate its failure processes during temperature change, a coupled thermo-mechanical model, which is on the basis of statistical damage model, is proposed. The model revealed the effect of the heterogeneity on concrete, and by analysis one of the important thermal stresses, i.e. thermal mismatch stresses, which are caused by thermal mismatch between the aggregate and mortar due to uniform change in temperature, it indicate that the presence of thermal mismatch causes stress concentration along the interface between aggregate and mortar, and the superpose of those stresses cause the crack propagation in the line of the two aggregate. The crack patterns, simulated by the proposed model, show a good agreement with the experimental results.
Authors: Tao Xu, Ju Ying Yang, Chun An Tang, Shi Bin Tang
Abstract: A coupled thermo-mechanical model is employed to analyze the thermo-mechanical behavior of a widely used laminated composite subject to temperature decrease at service conditions. Three sets of governing equations, i.e. heat transfer, thermo-mechanical deformation and damage evolution are respectively described in the model. These equations are then assembled into a coupled matrix equation using finite element formulation and then solved simultaneously at each time interval. A numerical model of two layered composites with some preexisting equal-spacing cracks along the interface in the lower layer is set up to investigate the thermal induced crack propagation due to temperature decrease. Results are presented in the form of crack propagation process in stress profiles and discussed. Numerical simulations show that the crack propagation behavior of the composites is closely dependent on the physico-mechanical properties of two layers and preexisting cracks. It is found that thermal induced cracks penetrate into the upper layer and grow in the upper layer due to the low strength of the upper layer when the model is subject to uniform temperature decrease.
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