Research On Cupronickel B10 Dynamic Pure Shear Constitutive Model Based On Spilt Hopkinson Pressure Bar Test

As a mainstream advanced technology,High-speed cutting has been deeply researched.Under High-speed cutting conditions,shear and compress deformation are simultaneity in the primary zone.So the internal friction of materials certainly exist in the primary zone.The inner friction of material is directly affected by the ratio of shear yield stress to compress yield stress(?s/?s)of the workpiece material,but it is difficult to directly research the composite stress under High-speed cutting conditions.Using dynamic mechanical experiments to simulate High-speed deformation in High-speed cutting,study the dynamic characteristic of materials,and establish the constitutive model,which is an excellent method for studying the stress under High-speed deformation of the material.At present,there is no suitable High-speed pure shear deformation experimental device and its constitutive model,and there is no internal friction model based on High-speed shear deformation.Cupronickel B10 is selected as the material basis.Through the research method of the dynamic pure shear test of the split Hopkinson pressure bar(SHPB),a pure shear JC constitutive model of B10 material including strain hardening benefit and strain rate strengthening benefit was established.In this paper,a new high strain rate pure shear experimental device is designed.This paper used this new device to complete the dynamic pure shear test of B10 material based on SHPB,the strain rate range is 8400?20600s-1.The quasi-static pure shear test is performed by the new device under the strain rate of 10-3s-1.The pure shear constitutive model of B10 material including strain hardening and strain rate strengthening was established.Finally,combined with the existing B10 material compression constitutive model,based on the ratio of(?s/?s,),the shear-compression(internal friction)constitutive model of B10 material is established.According to the shear-compression strain empirical ratio(?),the internal friction coefficient curve is drawn.In this paper,it is found that the shear fracture of B10 material requires large strain,and the rheological property is obvious when the strain rate is below 17400 s-1,but the thermal softening effect is dominant when the strain rate is above 18800 s-1.It is also found that the internal friction coefficient of B10 material has a maximum value of 0.52 near the compressive strain of 0.46.Under the high-speed cutting condition,the maximum internal friction coefficient of B10 material is 0.52,which is very close to the classical Mises criterion.But it's different to the classical theory,the internal friction coefficient is not a constant.In this paper,the problem of a high strain rate pure shearing device is solved.The pure shear constitutive model of the material is innovatively established for pure shear deformation.The shear-compression constitutive model of the material is innovatively built,based on the ratio of(?s/?s).The shear-compression constitutive model provides a theoretical basis for studying the internal friction problem of workpiece materials in high speed cutting.And have a certain degree of guiding significance for high-speed cutting.