Study On Failure Process Of Reinforced Concrete Structure Based On Peridynamics

Reinforced concrete structure is widely used in construction,bridge,national defense engineering and other projects.Its damage is often accompanied by the germination and expansion of cracks.The appearance of cracks not only causes the discontinuity of the structure,but also affects the stress distribution around the cracks,greatly reduces the rigidity of the structure,and finally leads to serious cracks and even fracture surfaces,which brings great safety to the project All hidden dangers may cause major property losses and casualties.Because the accurate analysis of the failure process of reinforced concrete structure is the basis of studying its failure mechanism and evaluating its performance,how to accurately analyze the process of crack growth has been one of the key issues in the research of reinforced concrete structure.In the field of civil engineering,the numerical method based on traditional continuum mechanics,represented by the finite element method,has been widely used.However,when simulating the discontinuity in the process of structural failure,such as the crack initiation and propagation,there will be the problem that the partial derivative does not exist in the discontinuity,so it can not accurately describe the structural failure.Peridynmics(PD)is a numerical method based on the idea of nonlocal action,which takes the integral form as the equation of motion.It solves the singularity problem of traditional continuum mechanics in dealing with the discontinuous problem.It has unique advantages in simulating the crack initiation and propagation.It has become the research hotspot of international computational mechanics and engineering simulation and related fields.However,the traditional Peridynmics model(PMB)still faces the limitation of Poisson’s ratio when simulating structural failure.On the basis of PMB model,considering the rotation of material point pairs,this paper breaks through the limit of Poisson’s ratio to a certain extent,adopts the damage model which can describe the tensile compression anisotropy and fracture characteristics of concrete materials,introduces the grading loading,dynamic relaxation,balance convergence criteria and rigid body impact contact algorithm,and establishes a near model which can accurately describe the failure process of reinforced concrete structure Peridynamics Micropolar model.Firstly,the accuracy of the Peridynmics Micropolar model of reinforced concrete structure proposed in this paper is verified by the quantitative calculation of linear elasticity,three-point bending failure and kalthoff-Winkler impact test simulation of plain concrete beam.Then,in order to simulate the bond slip between steel and concrete,this paper introduces the weakening coefficient of tensile micromodule and bending micromodule,selects the appropriate weakening coefficient through the pull-out test simulation,simulates the four point bending of reinforced concrete beam under the action of quasi-static force,analyzes the crack propagation process and the final failure form of reinforced concrete beam with shear span ratio And the shear failure of cantilever beam is simulated.Then the drop impact of reinforced concrete beam is simulated,and the response and failure mode of concrete beam with or without web reinforcement are studied.Finally,the problem of reinforced concrete slab impacted by projectile is simulated and analyzed.The whole process of reinforced concrete slab failure under the same impact energy is studied,and the influence of different constraints on the failure process of concrete slab is studied.It provides an effective new way to solve the failure simulation of reinforced concrete structure in civil engineering.