Simulation of shearing by node separation method

Abstract The objective of the present work is to clarify ductile fracture phenomena in bulk metal forming, by means of finite-element analyses and experiments. We have developed a computer program, based on a conventional computer program of the finite-element method, with which the behavior of crack growth after ductile fracture can be analyzed. The phenomenon that a material is divided into two materials upon shearing has been simulated by the program, and the following results were obtained. First, in order to perform a precise simulation, we have developed a method of representing the sharp change in the direction of material flow at the tool corners, a method of controlling tool displacement so that an element is fractured in each step and a method of separating nodes at fracture. Second, analytical results of the shape of the sheared surface, the shape of the fractured surface, the length of the sheared surface, the length of the fractured surface and the relationship between the punch displacement and punch force are found to agree with the experimental results. Hence, we have confirmed the validity of the methods.

[1]  A. Atkins,et al.  On cropping and related processes , 1980 .

[2]  F. W. Travis,et al.  Static and dynamic blanking of steel of varying hardness , 1970 .

[3]  Paulo A.F. Martins,et al.  Fracture predicting in bulk metal forming , 1996 .

[4]  Kozo Osakada,et al.  Simulation of severe plastic deformation by finite element method with spatially fixed elements , 1983 .

[5]  A. Needleman,et al.  Void Growth and Local Necking in Biaxially Stretched Sheets , 1978 .

[6]  A. Moisan,et al.  Finite Element Analysis of Ductile Fracture and Defects Formation in Cold and Hot Forging , 1990 .

[7]  A. J. Organ,et al.  Some factors affecting the quality of cropped billets , 1967 .

[8]  Z. Marciniak,et al.  The mechanics of sheet metal forming , 1992 .

[9]  Kazutake Komori.  Simulation of chevron crack formation and evolution in drawing , 1999 .

[10]  Taylan Altan,et al.  Material fracture and burr formation in blanking results of FEM simulations and comparison with experiments , 1996 .

[11]  J. M. Jalinier,et al.  Damage in sheet metal forming—I. Physical behavior , 1982 .

[12]  N. N. Kishore,et al.  Finite-element analysis of the blanking process , 1989 .

[13]  Bradley Dodd,et al.  Ductile fracture and ductility , 1987 .

[14]  J. Rice,et al.  Limits to ductility set by plastic flow localization , 1978 .

[15]  V. Tvergaard.  Numerical study of localization in a void-sheet , 1989 .

[16]  N. Fleck,et al.  Softening by void nucleation and growth in tension and shear , 1989 .

[17]  W. Johnson,et al.  The effects of temperature, speed and strain-rate on the force and energy required in blanking , 1967 .

[18]  S. Clift,et al.  Fracture prediction in plastic deformation processes , 1990 .

[19]  F. Mcclintock,et al.  Ductile fracture by hole growth in shear bands , 1966 .

[20]  Takashi Jimma.  The Theoretical Research on the Blanking of a Sheet Material , 1963 .

[21]  P. B. Popat,et al.  A new approach to the mechanics of the blanking operation: Theoretical model and experimental verification , 1985 .

[22]  Kazutake Komori.  Rigid-plastic finite-element method for analysis of three-dimensional rolling that requires small memory capacity , 1998 .

[23]  Y. Yamada,et al.  Plastic stress-strain matrix and its application for the solution of elastic-plastic problems by the finite element method , 1968 .

[24]  Elisabetta Ceretti,et al.  Simulation of Metal Flow and Fracture Applications in Orthogonal Cutting, Blanking, and Cold Extrusion , 1997 .

[25]  V. Tvergaard.  Influence of voids on shear band instabilities under plane strain conditions , 1981 .

[26]  I. Pillinger,et al.  Finite-Element Plasticity and Metalforming Analysis , 1991 .

[27]  J. Oudin,et al.  The experimental and theoretical analysis of plastic flow during the closed-die cropping of rectangular bars , 1979 .

[28]  Shiro Kobayashi,et al.  Metal forming and the finite-element method , 1989 .

[29]  Tomasz Wierzbicki,et al.  A tension zone model of blanking and tearing of ductile metal plates , 1996 .

[30]  A. Gurson.  Continuum Theory of Ductile Rupture by Void Nucleation and Growth: Part I—Yield Criteria and Flow Rules for Porous Ductile Media , 1977 .

[31]  Y. Bai,et al.  Plugging: physical understanding and energy absorption , 1982 .