Numerical Simulation Research On SHBP Experiment Of Concrete Based On Mesoscopic Mechanics

Concrete is widely used in all types of construction projects nowadays because of its excellent mechanical properties. Concrete is not only under static loads, but also bear the collision impact and explosion dynamic load, especially such as pier, dam, mine safety support engineering and military protection engineering, relating to people’s livelihood and national security. It is increasingly important and urgent to study mechanical properties under dynamic load and failure process and failure criterion.Most previous studies will deem concrete to mean and homogenized macroscopic continuum, but actually the material inside includes coarse aggregate concrete, cement mortar, weak aggregate interfacial transition zone around the pores and cracks, showing a multiphase uneven resistance, especially at high speed dynamic action,the impact of each phase medium properties of concrete will be highlighted. Hopkinson(SHPB) experiment is the most widely used method to study the dynamic properties of the concrete, which were born or validated with many dynamic properties of concrete research results. Therefore, the paper has important value and significance of studying the influence of Hopkinson(SHPB) experimental results to concrete aggregate size and content, mortar strength, interface from the microscopic point.Summarize the main factors influencing the dynamic strength of concrete from a lot of literature at home and abroad. Display dynamic analysis using ANSYS / LS-DYNA, around each phase of the sensitivity of medium strength concrete action to start work.The specific work is as follows:(1) The paper has produced random position of aggregate particles in the specimens in cylinder, and established two-phase and three-phase mesoscopic numerical model by using the Monte Carlo method,generating finite element mesh automatically, and recognizing variousunits and assign material parameters automatically.(2) The paper has derived aggregate and mortar HJC effective constitutive model parameters through experiments and theoretical studies.(3) Establish concrete SHPB computing model, combining one-dimensional stress wave theory and concrete strength effectiveness rate correlation, validation of the model.(4) Design numerical experiments from the two-phase and three-phase model, the parameters of each phase studied include: the combined effect of aggregate gradation, aggregate content, mortar strength and interfacial strength of the overall dynamic strength concrete.