Numerical Simulation Of Dynamic Mechanical Properties Of Two-gradation Random Distribution Polygonal Aggregate Concrete

Concrete has the advantages of pressure resistance,corrosion resistance,good permeability,wide source,low price and easy to make.As the most widely used building material,It is widely used in civil engineering,oceanographic engineering,defense construction and other military and civil fields.In addition to the normal design load,the concrete also needs to bear the dynamic load,such as impact and explosion.And it should have the capability of resisting impact and penetration.In order to explore anti-explosion capacity of two-gradation concrete with polygonal coarse aggregate and the influence of different coarse aggregate gradation and shape on the dynamic mechanical properties of concrete,the dynamic mechanical properties of two-gradation concrete with polygonal coarse aggregate was analyzed by using finite element software ANSYS/LS-DYNA and the poster processing software LS-PREPOST.The specific research is as follows:(1)The dynamic impact test of concrete with SHPB test device was used to analyze the experimental results;The study used the APDL language to write the aggregate release program,prepared random distribution of polygon aggregate,and then built the finite element model of concrete.(2)The study analyzed the effect of particle size and volume fraction of polygonal coarse aggregate and specimen size on the dynamic mechanical behavior of two-gradation concrete.The dynamic characteristics of concrete are studied by changing the grade and aggregate shape of the concrete,and then the relationship between coarse aggregate shape,gradation and concrete bearing capacity can be analyzed.The main conclusions are as follows:①Under impact load,the microcrack mainly occurs in the large strain region,then rapidly expands,leading to damage.As the impact velocity increases,the area of crushing becomes larger and the number of broken pieces increases;②Simulated results showed that two-gradation concrete was rate-dependent and had size-effect;③With the Growth in the maximum diameter of polygonal coarse aggregate,the bearing capacity of two-gradation concrete declines.The bearing capacity of two-gradation concrete increased first,and then decreased with the middle diameter and volume score of polygonal coarse aggregate.With the increase of the minimum diameter,the bearing capacity of two-gradation concrete declined;④When the concrete gradation is changed from single stage to two-stage,the bearing capacity is increased;⑤Compared with the bearing capacity of round coarse aggregate concrete,the bearing capacity of polygonal coarse aggregate concrete is higher.