Research On Formability Of Perforated Sheet In Incremtal Forming

Incremental forming technology as a kind of flexible manufacturing technology,related research has made great development,but incremental forming process of perforated sheet is still in the initial research stage.With the wide application of perforated sheet,further studying formability on incremental forming of perforated sheet for the development of incremental forming of perforated sheet and expanding incremental forming application fields has a good role in promoting.This paper uses incremental sheet forming and incremental sheet punching on the perforated sheet.The related fundamental problem on the formability of perforated sheet incremental forming is studied through the experiment and numerical simulation.Through the fixed angle cone cup experiment verified the feasibility of perforated sheet incremental forming,the results show that: in the two kinds of incremental forming process,circular hole in the deformed areas of perforated sheet is becoming into an elliptical hole;compared to the incremental sheet punching,incremental perforated sheet forming has relatively larger forming angler and smaller circular hole deformation.Through the perforated sheet numerical simulation,the results show that : the two incremental forming process are plane strain,the circular hole in forming region becoming into elliptical hole,and consistent with the experiment;the thickness variation is follows the sine law;contrasted to incremental sheet punching,incremental perforated sheet forming fluctuated range in strain,thickness and thinning rate are smaller;however,compared with incremental sheet forming,the mises equivalent stress fluctuated range of the incremental perforated sheet punching is smaller,and the forming force is smaller.Based on numerical simulation,using the Cockcroft&Latham criterion predicted the rupture failure in perforated sheet incremental forming,and the judged results show that: rupture failure predicted results of incremental perforated sheet punching is accorded with experimental results,the predicted result of incremental sheet forming has a certain error.In addition,the influence of process parameters on the formability of incremental forming in the perforated sheet is studied through experiments and numerical simulation.The results show that: in the process of incremental sheet forming,increasing the layer feed,with the decreased the forming limit angle,and tool diameter and feed speed of the incremental sheet forming has little effect on forming limit angle.When the perforated sheet circular hole diameter remain unchanged,increasing the center distance of hole size,forming limit angle of incremental sheet punching does not increased.Keep the perforated sheet holes center distance unchanged,corresponding to increase perforated sheet circular holes diameter size,incremental sheet punching limit angle is increased.Moreover,with the increase of the forming depth in process of incremental sheet forming,the region of the deformation in incremental sheet forming is increased first and then decreased,with the increase of deformation layer feed and speed,the deformation of the whole perforated sheet in forming region is relatively increased.