Study And Simulational Analysis Of The Mismatch Cross-sectional Area Effect On SHPB Experiment

The test results of material dynamic mechanics parameters are not always accurat byusing the split hopkinson pressure bar(SHPB) experimental device,especially for thematerial of high strain rate and the small strain.The main factors of the experimental erroris that the cross-section area of the specimen does not match with the pressure bar.Thisarticle will use the experiment and simulation method to establish experimental errorcorrection scheme, so as to reduce the error of the experimental test results.The article will use the SHPB experiment to test mechanical parameters of fivedifferent cross-section specimen.The dynamic compression simulation of specimen is byusing nonlinear finite element software,so as to observe the deformation of specimenunder the loading process,as well as transverse deformation of pressure bar contactingwith the specimen,and by comparing the simulation results with the experimental resultsto analysis the numerical simulation method is feasible or not.The function relationbetween the concave quantity of presssure bar and influence factors by dimension analysismethod,and the mathematical model of expemental error is established by using numericalexperiments to determine the main factors of concave quantity.The correction scheme ofmathematical model of experimental error and adding the revised block method haveestablished by aiming at the influence factors,and select the most optimal correctionscheme by compared with the results.The experimental results show that the elastic modulus of the specimen is greaterwith the increasing of the cross-section of specimen-pressure bar,but the deformation ofthe specimen is smaller.The simulation results show that the elastic sag is appeared in thecontact surface between pressure bar with the specimen,and the analyzing results showthat the numerical simulation method is feasible.The mathematical model of the test errorshows that the cross-section area ratio and load are the main factors that influence theexperimental error,and others can be ignored.Through the results of the error correctionscheme of mathematical model,the elastic modulus of specimen has improved aftercorrection,but is still large error with the real elastic modulus.The results of adding blockmethod show that the elastic modulus of specimen has great improvement after correction,and is small with the real elastic modulus.The adding block method is more feasible bycomprassion of two kinds of experimental error correction scheme.