Multi-crack Test And Numerical Simulation Of Reinforced Concrete Beams

The failure of reinforced concrete structures or components is the result of damage caused by the generation and development of cracks.With the socio-economic development and technological progress,concrete buildings are developing in a comprehensive direction with complex shapes and various functions.The development of cracks in the process of destruction is analyzed using computer technology as an auxiliary or even the main method.Examining the existing numerical analysis methods,many scholars use single or two cracks as simulation results for analysis of cracks,and rarely give numerical analysis results consistent with the actual situation.In view of the above phenomena,this paper uses a common component reinforced concrete bending beam to carry out numerical analysis of concrete with multiple cracks.The accuracy of numerical simulation depends on the rationality of material theory selection under related issues and the handling of interactions between different materials.In view of the two major mechanical characteristics of concrete materials,such as stiffness degradation and irreversible deformation during the actual stress process,this paper uses the theory of plastic damage(CDP),which combines classical plasticity theory and damage theory,to analyze crack propagation.On the basis of the existing research on the model,we explain in depth the differences between the concepts of damage in CDP and damage theory,as well as the value methods.With the help of ABAQUS finite element software,a material nonlinear numerical model for simulating the failure behavior of reinforced concrete beams is established,and a fully bonded relationship is adopted for the action between steel and concrete.Based on the comparison of four-point bending test and numerical simulation of reinforced concrete beams,the development path of multiple cracks in reinforced concrete beams is studied.Based on the good agreement between the two results,the bond slip behavior between reinforced and concrete is extended and simulated.The analysis results show that: 1)The damage factors were used to judge the cracking failure of concrete,and the multiple cracks with complete bond simulation evolution were expressed in the form of continuous damage bands,and the distribution of damage bands was consistent with the crack development path during the failure process of the test beam.2)Based on the study of multiple cracks,the bearing capacity of the fully bonded simulated beam exists within the range ofexperimental values;in the comparison of the load-displacement curves,the overall stiffness of the finite element model during the failure process is greater than that of the test.3)Although the bearing capacity of the bonded-slip simulation beam is reduced to be close to the test minimum,the load-displacement curve calculated by the bonded-slip simulation beam relative to the fully-bonded simulation beam is more suitable for the test in the middle of loading.And the evolved damage bands are highly consistent with the test results.