Fractal Simulation Analysis Of Crack Propagation Path Of Reinforced Concrete Beams

Damage Cracking Behavior of reinforced concrete structures has attracted more and more attention,and many scholars through the test of reinforced concrete beams to study the beam surface crack growth.While the main theoretical basis is still the traditional classic damage and fracture mechanics theory,the assumption of concrete fracture surface and crack propagation path is flat and smooth.But the actual cracking of concrete material is not the case.In view of concrete crack surface irregularity and roughness,research on reinforced concrete beam crack propagation path by using the traditional mechanics theory will cause the inaccuracy of the results.In this paper,fractal geometry theory and fracture mechanics theory are used to analyze the problem of the irregularity of the crack propagation path,and on the basis of summarizing the existing research,through the comparison of the related data of four point bending test and numerical simulation of reinforced concrete beam,to study the following problems,the mechanical characteristics of cracks in reinforced concrete beams,the relationship between the fractal characteristics of the beam crack propagation path and the corresponding mechanical parameters,and the simulation of the fractal expansion of concrete cracks.The specific research work is as follows:(1)Based on the theory of fracture mechanics,the internal damage and fracture mechanism of reinforced concrete members are analyzed,and clearly understand the process of crack propagation,generation and propagation of concrete.On the basis of this,the crack formation and expansion of concrete and other brittle materials are studied by using the virtual crack propagation model.(2)In order to give full consideration to the irregularity and roughness of the crack propagation path,the fractal theory and the fracture mechanics theory are combined.The crack growth law of reinforced concrete beam is analyzed by the fractal curve to construct the concrete crack boundary and through the relationship between the fractal dimension and the corresponding fracture parameters,the evolution law of crack propagation in reinforced concrete beams is analyzed.(3)By means of four point bending test of reinforced concrete beams,the crack propagation paths of reinforced concrete beams are studied by fractal theory.Come to the conclusion that the relationship between external load,crack width,and fracture energy of concrete material and the fractal dimension of crack propagation path.The fractal dimension can be used as a basic parameter for evaluating the crack propagation of concrete materials.(4)Finite element numerical simulation of reinforced concrete beam is carried out by using the extended finite element method,to further research on stress distribution in the crack propagation process of test beam under different loads and its path fractal characteristics.It is concluded that the numerical simulation and the experimental results have good agreement with the experimental results.(5)Based on the test of reinforced concrete beams,It is proved that the fractal dimension can describe the variation characteristics of damage and fracture parameters of concrete materials,and simulate the expansion path of concrete crack with the basic principle of fractal interpolation.