Effect Of Surface Processing Integrity On Self-organization Behavior Of Shear Bands In Cylinder

The destruction of metal cylindrical shells under extreme conditions has always been one of the focuses of defense aviation and military industry.Adiabatic shear fracture is a common failure phenomenon of metal cylindrical shells when they are subjected to explosive loads.It is important and valuable to study the formation mechanism of adiabatic shear fracture in the field of military industry and aerospace.In this paper,Two-dimensional plane strain models of 45 carbon steel cylindrical shells with different plastic layers and different surface geometric defects were established by using the finite element simulation software ANSYS/Workbench software to numerically simulate the TWC test.The effects of plastic layer and surface geometric defects on the adiabatic shear behavior of 45 carbon steel cylindrical shells were study with equivalent plastic,train,stress,shear band pattern analysis and other methods.And it is the following conclusions:(1)The number of nucleation of the cylindrical shell shear band increased and the shielding effect of the development of cylindrical shell shear band are more distinct with increasing the thickness of the plastic layer on the inner surface of the shell.And the plastic layer changes the development direction of shear in the area of the 45 carbon steel cylinder,forming a single-rotation phenomenon of the shear band.When the thickness of the plastic layer on the inner surface of the cylinder is small,the number of shear band cores in the cylinder is less than that of the cylinder without plastic layer Medium shear band nucleation;when the thickness of the plastic layer increases to a certain extent,the shear band nucleation of the cylindrical shell with the plastic layer is greater than the shear band nucleation of the cylindrical shell without the plastic layer(2)The cylindrical shell first forms a shear band at the surface defect with the disturbance amplitude of the surface defect increases,the development speed and width of the shear band in the cylindrical shell increase,and the shielding effect of the main shear band on the surrounding shear band increases.However,the disturbance amplitude has no obvious influence on the direction of the final shear band.Using the influence law of the surface abrupt change point geometry point on the shear band,by designing the geometry of the surface defect on the inner surface of the cylinder,the development direction of multiple shear bands in the cylinder is controlled,and the single spiral distribution shear is obtained by simulation Cut with patterns.(3)With the increase of the defect density on the inner surface of the cylinder,the distance between the geometric mutation points of the inner surface of the cylinder is reduced and the influence of the shielding effect on the development of the shear band of the cylinder is enhanced.The new shear band shape in the area around the main shear band is also reduced.nuclear.