| Because of its wide use as a major construction material in practice, concrete has attracted much attention regarding its fracture and failure study.The influence of slow crack propagation ahead of the crack tip upon the nonlinearity observed in the typical load-deflection response of the concrete specimen. Crack has significant influence on endurance, safety and bearing capacity of concrete structure and has become an importantindex for determining whether concrete structure shall be strengthened.The extended finite element method (XFEM) is a numerical method for modeling discontinuities within the classical finite element framework developed in recent years. In this paper, use it is advantage to the application of fracture mechanics, using the virtual crack closure technique to calculate the strain energy release rate, the application of the maximum circumferential stress fracture criterion to determine the direction of crack. Based on the linear elastic mechanics, carried out a large gate_dam cracks the process to numerical simulation. This paper research content mainly includes the following aspects:(1) The theory of fracture mechanics and basic principles of extended finite element method are researched. Introduced in detail the calculation of stress intensity factor of numerical method and crack representation in the extended finite element method.(2) Based on the extended finite element method, calculated two classic frac-ture mechanics stress intensity factor and the calculated results with the analytical solution compared to verify the correctness of the calculation method. In addition, on the basis of linear elastic mechanics, the four-point shear concrete model of crack propagation analysis, the crack propagation paths were compared with experimental results, analysis of its influencing factors. (3) Select a large concrete Gate_dam project for the study, three-dimensional solid model is established, used the extended finite element method numerical simulation analysis to study the release flood waters washed sand road section crack propagation law and the safety of the dam, and further study the foundation for crack propagation. |
PDF Full Text Request