| In recent years,people have done a lot of research on the establishment of metal materials,constitutive model and fracture criterion.In the past,many scholars only considered the influence of stress triaxiality on the fracture strain of materials when studying the fracture failure of materials,and achieved many successful predictions.However,in recent years,domestic scholar Xiao Xinke found that the impact damage of metal materials is not only related to the stress triaxiality,but also to the Lorde angle.In this paper,the constitutive failure model of Taylor impact damage of W900 E steel is studied by means of numerical simulation and experiment,which is the Lode correlation of material under impact damage.The main work done in this paper is as follows:1.The quasi-static tensile test of the smooth and notched round bar specimens under room temperature,the dynamic compression test of the cylindrical specimens and the high temperature quasi-static tensile test of smoothing round bar specimens.were carried out using universal material tensile testing machine,DIC(video extensometer),Hopkinson pressure bar and high temperature furnace.In order to calibrate the Lode angle-related ASCE fracture criterion,plane strain and plane shear tests were additionally performed.According to the test data obtained from the material test,the relevant parameters in the constitutive failure model are calibrated.2.In order to study whether the Taylor impact damage behavior of W900 E is related to Lode angle,the Taylor impact test of W900 E was carried out,different deformation modes of bullets at three speeds were obtained in this experiment.3.The three-dimensional finite element simulation model of Taylor impact was established by Abaqus/standard.The fracture criterion use the Lode angle-related ASCE fracture criterion and the modified JC criterion.Verifying the Lode angle correlation of W900 E Taylor impact failure behavior by comparing numerical simulation and experimental results.In this paper,the following conclusions are obtained through the basic material test,comparing the results of numerical simulation prediction and Taylor impact test;1.The strain hardening effect and temperature softening effect of W900 E are significant,and the strain rate strengthening effect is not significant.The tensile loaddisplacement curves obtained by the simulation using the constitutive strain hardening parameters of the smooth circular bar specimen under quasi-static stretching are quite different from the plane strain and plane shear test curves,thus need to optimize constitutive strain hardening parameters.The plastic flow behavior is affected by the Lode angle parameters.2.It is concluded that for the Taylor impact damage of W900 E,the introduction of Lode angle in the fracture criterion can improve the accuracy of simulation calculation.The bullet deformation results predicted by the modified JC fracture criterion without considering the Lorde effect are all upset deformation.The predicted material toughness is significantly higher than the test results.That is,the Taylor impact damage behavior of W900 E has certain Lode angle correlation. |
