Application Of Cohesive Traction Crack Model In Crack Propagation In Concrete

The concrete structure is currently the most widely used structural forms. It hasbeen successfully applied to industrial and civil buildings. Because of characteristics ofthe materials used in the concrete structures and complexity of the environment,concrete structure will inevitably be cracking and performance deteriorated, which willresult in durability problems. The mechanical behavior within the fracture process zoneat the tip of crack in concrete can be well described by the cohesive traction crackingmodel. The softening curve of concrete, reflecting the relationship of the residualintensity and crack width after its reach tensile strength, is a significant part of thecohesive traction cracking model. In this paper, concrete crack propagation process isstudied based on extended finite element method and cohesive traction cracking model.The main works are as follows:(1)In this paper, linear softening curve and nonlinear softening curve was analyzed,and then the multi-stage curve of softening constitutive model was advanced. using thecurve of the numerical simulation results were compared with corresponding data in theliterature, shows that multi-stage softening curve on the said the softening behavior ofconcrete has a certain credibility and effectiveness.(2)Studied the cohesive traction cracking model to determine the initial cracklocation, as well as the traction-separation principle implementation used in ABAQUS,Iterative algorithm is introduced for Ⅰ type fracture extension, and The iterationalgorithm of complex crack are put forward.(3)using iterative algorithm ofⅠtype fracture extension, on the finite elementsoftware ABAQUS platform concrete beam is analyzed in the process of componentfracture crack extension process and component of the load crack mouth openingdisplacement curve, compared simulation results with the analytic solution of theproblem to verify the accuracy of numerical methods to analyze the crack propagationproblem. Compared complex crack propagation problem with experiment, the Angle ofthe crack propagation and experimental observation data are consistent. It proves thatthe extended finite element method to capture the advantage of the complex shape crackproved that the finite element capture the advantage of the complex shape crack extension. Constitutive relation is analyzed using the proposed model of crackpropagation of concrete gravity dam and crack distribution regularity of stress,Verify thevalidity of the model.