Analysis Of The Mechanical Behavior Of Cracking Concrete Surfaces

Normally, cracks in the concrete components will be carried out along the most unfavorable position. However, cracking concrete components is not completely unable to continue to bear the load, both sides of the crack surface are rough and irregular, so it can produce certain size friction after sliding. Once the concrete slides, it can form the shear stress, which resists loads acting together with the shear reinforcement. As for the concrete structures after cracking, how much the shear stress can pass? Whether has the coefficient mathematical statistics regularity of shear transferring? The current research did not get an exact conclusion. This paper put forward a proposition on analysis of mechanics behavior of cracking concrete surfaces, aiming at resolving the mechanical behavior of two matching rough concrete cracking, thus providing the mechanical theory of foundation for concrete components crack propagation region of shearing force calculation.This paper was based on the theory of contact mechanics, through the comparative analysis people found that the rough outline of cracking concrete, showing self affine similarity characteristics, is similar to the fractal contact model. Therefore, we can apply fractal theory to study rough concrete contact interface. This paper generated the concrete rough contact interface respectively through the adoption of the corrected midpoint displacement method and W-M function method, which belong to the fractal theory, then with the help of nonlinear finite element software ABAQUS, I established a contact model of concrete material as analysis object, and carried on the numerical analysis.Contact model in this paper was adopted the shape of the ball cap for asperity contact. This paper firstly analyzed the relationship of a pair of asperity contact with the pressure of contact and the area of contact, then obtained the nonlinear relation curve. Then graph shows the relationship of the contact pressure-area and contact pressure-displacement, comparing with the budget results of the Hertz theory, I found that the present results were very close to the budget results with Hertz theory, so as to verified the correctness of the model. In order to verify the influence of rough surface morphology of contact area, with different friction coefficient in the model, finally found that the friction factor of a single asperity has a little of impact on the contact area.In order to further verify the asperity contact on the mechanical behavior characteristics, this paper expanded the contact model by extending a pair of asperity to seven pairs contact to contact, and 14 balls cap height belonged to the modified exponential fitting of gauss distribution. Through the analysis and calculation of ABAQUS, got the relationship between the enlarged contact pressure and contact area. The results showed that considering the multiple asperities, the relationship of contact pressure-area was linear relation, and the friction factor was stable. The ratio of tangential force and vertical force coefficient conforms to the linear decrease, and in conformity with the W-M model theory.