RESEARCH ON NON-PRANDTL SOLUTION OF COARSE PLANE PUNCH PIN PRESSED IN THE SEMI-UNFINITE BODY IN SLIP LINE TEACHING

It is difficult for students to understand that the calculation results of smooth punch and coarse punch pin pressed into semi-unfinite body are the same in slip line teaching. A non-Prandtl slip line field of coarse punch pin pressed into semi-unfinite body is proposed and constructed. Compared with solution of Prandtl field, the unit pressure and coefficient of stress state are increased by 11% because of friction. Furthermore, the normal stress in x direction is increased by about 82% compared with the calculation results of smooth punch pin pressed in semi-unfinite body. The calculation results reflect accurately the influence of friction on increasing plastic deformation force, and it is helpful for students to study and apply the slip line theory.