Discrete Element Simulation Of Anti Impact Properties Of Hybrid Fiber Reinforced High Strength Concrete

Two or more of the hybrid fibers are added to the concrete matrix,in which interweave the perplexing network,and have a stable effect on concrete materials,reinforce and toughening the concrete matrix,and synergy to enhance strength and toughness of the matrix.The preparation of the steel fiber volume fraction is 0 to 2 percent,polypropylene fiber volume rate is 0 to 0.1 percent,parameters of fly ash is 0 to 30 percent,silicon powder content is 0 to 20 percent,and strength grade of the HFRHSC is C40 to C80.Studying the lever of these four factors on HFRHSC mechanical property and shock resistance research,theoretical analysis and numerical simulation,the main research results are as follows:SHPB dynamic compression test study found that concrete is a strain rate sensitive material,During the SHPB test,the failure of concrete test block will occur when the strain rate sensitive ranges from 51/s to 56/s.When the strain rate is not reached,the peak stress of concrete is increased slowly.In this stage,with the change of the strain rate,the peak stress amplitude is smaller,and the test block is not obviously damaged after the SHPB test.The model of block is established by using the particle flow software EDEM,and the fine microscopic parameters of the HFRHSC are calibrated.Through the analysis of the influence of the parameters,the results show that the bond radius and bond strength of the particles are positively affected by the peak strength of the specimen,and the bond stiffness has a negative effect.EDEM is used to simulate the dynamic compression of HFRHSC,and the failure process of the specimen under transient impact is reproduced,and the failure mode of HFRHSC block is obtained.The whole process of failure of the test specimen is similar to that of the real test,which shows that the dynamic compression failure process of the HFRHSC is high reliability.