Study On Dynamic Compression Performance Of Barite Concrete Based On SHPB Test

Because of rich raw materials,low price and excellent radiation resistance,barite concrete has been widely used in national defense,medical treatment,nuclear energy construction and other special projects.However,at present,the research of this material is still on its quasi-static mechanical properties,and the dynamic research of this material at medium and high strain rate is very few.Therefore,in order to supplement the dynamic research of Barite Concrete under impact load,the following two works have been completed:（1）Adopting theφ100mm split Hopkinson pressure bar（SHPB）device of University of South China,under the 5 loading conditions,the dynamic compression tests of barite concrete and ordinary concrete with 3 strength grades of C30,C40 and C50 were carried out respectively.Under the strain rate of 31s^-1-128s^-1,the differences and similarities of the dynamic compression properties of the two materials are compared and analyzed.In consideration of the influence of the strength grade of the materials,the test results are described in five major points,namely,the test reliability analysis,the test phenomenon,the original waveform,the stress-strain curve and the strain rate effect.（2）Under this test condition,the SHPB simulation analysis of Barite Concrete is completed by LS-DYNA program and K&C model.Compared with the experimental data,the simulation also made a comprehensive consideration of the dynamic compressive properties of barite concrete under the influence of strength grade factors from 4 aspects,including specimen failure,stress-strain curve,dynamic compressive strength and dynamic compression deformation.At last,according to the results of experiment and simulation,this paper completed a comprehensive qualitative analysis of the dynamic compression response of Barite Concrete under the strain rate of 23s^-1-128s^-1,which provided a reference for the design,analysis and application of the material under the impact load.The results show that:（1）With the increase of strain rate,the failure mode of Barite Concrete follows the evolution process from fracture to crushing,and with the increase of strength grade,the above failure evolution process of material will slow down.（2）Compared with ordinary concrete,the critical position of rate sensitivity of Barite Concrete will be relatively delayed,and the critical value of strain rate may be between 62s^-1-101s^-1.（3）The mechanical properties of Barite Concrete have strain rate effect.With the increase of strain rate,the compressive strength and compressive strength DIF value（Dynamic Increase Factor）,peak strain and ultimate strain of materials will increase to varying degrees.Under the same loading condition,with the increase of strength grade,the brittleness of the specimen increases,the ductility decreases,and the DIF value of compressive strength slightly decreases.