Finite Element Analysis And Simulation Of Concrete Experiment Based On Meso-mechanics

The relationship between the macro-mechanical properties of concrete and its micro component materials can be established by the meso-mechanical analysis method and numerical simulation.Compared with the traditional macro experiments of concrete,the meso-mechanics numerical simulation of concrete can overcome the limitations of macro experiments conditions and solve time-consuming and laborious defects,but how to choose a more reasonable numerical model and expand the application scenarios still need to be supplemented.In this disertation,the mesomodeling of concrete random aggregate model,the numerical simulation of concrete failure,and the influcing factor analysis of meso-material value are completed.The multi-scale numerical model of concrete is established and extended in the macro scale.At the same time,the meso analysis method is used to simulate the experiment process and improve the meso model of concrete.This method provides more application scenarios for the simulation of meso-mechanics.Based on the meso-mechanical analysis method of concrete,the generation method of aggregate and interfacial transition zone,the embedding mode of cohesive elements and the selection of material parameters in the modeling process of random aggregate model are deeply studied.In the process of modeling,the whole process of automatic modeling of geometric model is realized,and the recommended value of material information is given,forming a complete set of concrete finite element simulation methodology based on meso-mechanics.At the same time,the numerical simulation of the failure process of concrete under tension and compression is realized based on the meso model.Compared with the macro model,the change of damage and cracking morphology in the failure process of concrete can be observed more directly.The control variable analysis of the important material parameters in the concrete meso numerical model is carried out,and the results of the numerical analysis are compared with the requirements of the code.In the meso model of concrete,the shape and distribution of aggregate will change the development form and position of cracks.Increasing the tensile strength of the interface transition zone can increase the overall tensile performance of concrete.At the same time,its elastic modulus has no direct impact on the tensile performance of concrete.The relative strength relationship between meso materials will directly affect the development mode of cracks.In order to improve the efficiency of calculation,the multi-scale model modeling methodology is given.Based on this model,the cracking process of concrete beam under vertical load is simulated,and the vertical crack development process in the middle area of the beam is directly observed.The cohesive model is applied to the numerical simulation of the cracking process on the macro level of concrete innovatively,and the simulation effect of shear failure o f short concrete columns in the process of one-way compression failure is realized.Based on the process of self-healing of concrete cracks,the whole morphology,products and self-healing effect of cracks in the process of self-healing of concrete cracks were recorded and studied for 180 days.On the basis of observation and test,using the "actived and disactived element" technology in ABAQUS,combined with Monte Carlo method and the idea of element equivalence,the numerical simulation of concrete crack self-healing process is realized,and the evaluation method of concrete crack repair is improved.This research shows that the modeling methodology of concrete meso model proposed in this paper can effectively improve the efficiency of the modeling process,and at the same time,it can directly show the development process of cracks in the process of concrete failure.Besides,the application of cohesive model at the macro level can keep the effect of simulated cracking and high calculation efficiency.Base d on the experimental results,a numerical model of crack self-healing with time variable is proposed to evaluate the repair effect of concrete cracks directly from the meso material level.